POWER MULTIMETER

2721 / 2722
Instruction Manual

NF Corporation

DA00027017-003

2721/2722
POWER MULTIMETER

INSTRUCTION MANUAL

2721/2722

POWER MULTIMETER

USER’S MANUAL

date：2010/6/14

Note: “2722” has been discontinued, and therefore the descriptions in this document are forreference only.

The instruction manual with disorder pages or missing pages is to be replaced. Please get in touchwith NF Corporation or one of our representatives.

NOTE• Reproduction of the instruction manual, part or whole, is forbidden without prior written
permission.
• The contents of the instruction manual are subject to change without notice.
• Information provided in the instruction manual is intended to be accurate and reliable.
However, we assume no responsibility for any damage regarding the contents of the instruction
manual.
Copyright 1996-2010, NF CORPORATION

Preface

PrefaceThank you very much for purchasing our “2721/2722 POWER MULTIMETER”.
To ensure safe and proper use of this electric equipment, please read first “Safety
Precautions” on the following pages.

 Caution Symbols Used in This Manual
The following caution symbols are used in this manual. Be sure to observe these caution
symbols and their contents to ensure the safety of the user and avoid damage to theequipment.

！ WARNING
This symbol indicates information for the avoidance of a hazard such as
electric shock that may endanger human life or cause injury during handlingof the equipment.

！ CAUTION
This symbol indicates information for the avoidance of damage to theequipment during handling.

Note
This symbol indicates important information for the handling of this product.

 This manual has the following chapter organization:
1.

OVERVIEWThis chapter gives general description of the product, as well as the operating principle.

2.

PREPARATIONS BEFORE USE

This chapter describes important preparation before installation and operation. Be sure to readthis chapter.

3.

BASIC OPERATIONThis chapter describes the functions, operations, and connecting method of the panels, as well asbasic operations. Read this chapter while operating the device.

4.

COUNTER FUNCTION

This chapter describes the operations and settings of the counter.

5.

INTEGRATING FUNCTION

This chapter describes the operations and settings of the integrating function.

6.

SETTING OPERATION WITH SHIFT KEY

This chapter describes the setting operation using the SHIFT key, except basic operations.

7.

REMOTE CONTROL FUNCTION

This chapter describes the GPIB and RS-232C.

8.

TROUBLESHOOTING AND MAINTENANCE

This chapter describes how to deal with error messages and troubles, as well as operation checkand performance test.

9.

SPECIFICATIONSThis chapter describes the product’s specifications (functions and performance).

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Safety Precautions

Safety Precautions
To ensure safe use, be sure to observe the following warnings and cautions.
NF Corporation shall not be held liable for damages that arise from a failure to observe thesewarnings and cautions.

 Be sure to observe the contents of instruction manual.
This instruction manual contains information for the safe operation and use of this product.
Be sure to read this information first before using this product.
All the warnings in the instruction manual must be heeded to prevent hazards that may
cause major accidents.

 Be sure to ground the product.
This product uses a line filter and you will get shocked unless the product is grounded.
To prevent electric shock, be sure to safely implement grounding in according to Japanesetechnical standard of electrical equipment D (Type 3, ground resistance is less than 100Ω)
or better.
This product is grounded when its three-pole power supply plug is connected to the threepole power outlet having a protective ground connector.
When using a three-pole to two-pole conversion adapter, be sure to connect the grounding
wire (green color) of the adapter to the grounding terminal next to the outlet.

 Check the power supply voltage
This product operates on the power supply voltage indicated in “2.2 Grounding and Power
Supply Connection” in this instruction manual.
Before connecting the power supply, check that the voltage of power outlet matches the
rated supply voltage set with the Voltage Selector switch.

 Observe the fuse rating
Using an unspecified fuse could cause a fire. Use the rated fuse specified in “2.2 Grounding
and Power Supply Connection” of the instruction manual.
Also, when replacing the fuse, the power cord must be disconnected from the power outlet.

 In case of suspected anomaly
If this device emits smoke, an abnormal smell, or abnormal noise, immediately power it off
and stop using it.
If such an abnormal occurs, prevent anyone from using this product until it has been
repaired, and immediately report the problem to NF Corporation or one of ourrepresentatives.

 Do not use the product when flammable gas is present.
An explosion or other such hazard may result.

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Safety Precautions

 Do not remove the cover.
This device contains high-voltage parts. Absolutely never remove its cover.
Unavoidable internal inspections are to be performed only by service technicians who knowwhat is hazardous and have been adequately trained.

 Do not modify this product.
Never modify the product or replace the part with a part not authorized by NF Corporation,
which otherwise may cause new hazards and may disqualify this product from repair incase of a failure.

 Safety-related symbols
The general definitions of the safety-related symbols used on this product and in the
instruction manual are provided below.

！

Instruction Manual Reference SymbolThis symbol is displayed to alert the user to potential danger and refer him/herto the instruction manual.

警 告！ WARNING

Warning SymbolThis symbol indicates information for the avoidance of a hazard such as electric
shock that may endanger human life or cause injury during handling of theequipment.

注 意！ CAUTION

Caution SymbolThis symbol indicates information for the avoidance of damage to theequipment during handling.

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Contents

Contents
Page
Preface ···························································································································

1

Safety Precautions··········································································································

2

1. OVERVIEW··············································································································· 1 - 1
1.1 Features ··········································································································· 1 - 2
1.2 Principle of Operation ······················································································· 1 - 3
 Functional block diagram ·································································· 1 - 3
 Arithmetic expressions of measurements·········································· 1 - 4
1.3 Description of Functions ··················································································· 1 - 5
2. PREPARATIONS BEFORE USE·············································································· 2 - 1
2.1 Checking before Use ························································································ 2 - 2
 Unpacking and repacking ·································································· 2 - 2
 Standard configuration ······································································ 2 - 2
 Input Unit configuration (for ELEMENT 0) [Choose this option
when placing an order, if necessary] ················································· 2 - 2
 Micro-current probe configuration [Optional] ····································· 2 - 2
2.2 Grounding and Power Supply ··········································································· 2 - 3
 Grounding·························································································· 2 - 3
 Power supply····················································································· 2 - 3
 Line filter···························································································· 2 - 4
 Power fuse ························································································ 2 - 4
2.3 Installation ········································································································ 2 - 5
 Precautions ······················································································· 2 - 5
 Installation conditions ········································································ 2 - 5
 Handling of the panel and case ························································· 2 - 5
3. BASIC OPERATION ································································································· 3 - 1
Description of displayed characters ·········································································· 3 - 2
 Front panel ························································································ 3 - 3
 Side / Rear panel··············································································· 3 - 4
3.1 Operation at Power ON ···················································································· 3 - 5
 Display when the power is turned on················································· 3 - 5
 Display/setting of date and time setting mode··································· 3 - 6

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3.2 Connecting Voltage and Current Cables ·························································· 3 - 7
 Precautions when connecting voltage and current cables················· 3 - 7
 Connection for voltage measurement ··············································· 3 - 8
 Connection for current measurement ················································ 3 - 10
 Connection for power measurement ················································· 3 - 12
3.3 Setting Measurement Conditions······································································ 3 - 15
 Initializing the settings ······································································· 3 - 15
 Setting SYNC signal

SYNC ···························································· 3 - 16

 Setting measurement mode
 Setting wiring type

MODE················································ 3 - 17

WIRING ···························································· 3 - 17

 Hold function ····················································································· 3 - 17
 Measurement average function························································· 3 - 18
 Auto range setting ············································································· 3 - 18
 Scaling function················································································· 3 - 18
3.4 Setting Displays A, B, C, D, E, F ······································································ 3 - 19
 Selecting display item and input element ·········································· 3 - 19
 Operating STORE/RECALL (display switching) keys························ 3 - 19
 Operating FUNCTION keys······························································· 3 - 20
 Operating ELEMENT keys in phase measurement··························· 3 - 21
 Operating ELEMENT keys in line measurement ······························· 3 - 21
3.5 Measuring Voltage, Current, Power, Power Factor, and Phase Difference ······ 3 - 22
 Setting FUNCTION and ELEMENT··················································· 3 - 22
 Setting measurement conditions ······················································· 3 - 22
 Measuring voltage and current·························································· 3 - 22
 Measuring electric power ·································································· 3 - 22
 Measuring power factor····································································· 3 - 23
 Measuring phase difference ······························································ 3 - 23
3.6 Other Measurements························································································ 3 - 24
 Impedance measurement·································································· 3 - 24
 Frequency measurement ·································································· 3 - 24
4. COUNTER FUNCTION····························································································· 4 - 1
4.1 COUNTER FUNCTION ···················································································· 4 - 2
 Description of counter operation ······················································· 4 - 2
4.2 Counter Input Terminals ··················································································· 4 - 42721/2722

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ContentsPage
4.3 Setting Counter Measurement Conditions ························································ 4 - 5
 Setting time measurement mode (INTERVAL/ONE SHOT) ·············· 4 - 5
 Resetting the counter (RESET) ························································· 4 - 6
 Setting START or TRIP input type (CONT/VOLT)····························· 4 - 6
 Operation modes of START and TRIP inputs (B-M/M-B) ·················· 4 - 6
 Monitoring START and TRIP inputs ·················································· 4 - 7
 Chattering eliminating function (CHAT) ············································· 4 - 7
4.4 Counter Setting Mode······················································································· 4 - 8
 Counter setting mode (CNTMD)························································ 4 - 8
 Chattering time setting (CAT-SET)···················································· 4 - 9
4.5 Time Measurement··························································································· 4 - 10
 Time measurement method ······························································ 4 - 10
 Displaying counter data····································································· 4 - 10
 Time measurement range ································································· 4 - 11
5. INTEGRATING FUNCTION ······················································································ 5 - 1
5.1 Measuring Integrated Active Power, Current, and Reactive Power ·················· 5 - 2
 Integrate mode ·················································································· 5 - 2
 Integration display update cycle ························································ 5 - 3
 Display of integrated time·································································· 5 - 3
5.2 Integration setting mode (INT-MD) ··································································· 5 - 4
 Display of integration setting mode ··················································· 5 - 4
 Display of manual integrate mode ····················································· 5 - 4
 Displaying and setting time integrate mode······································· 5 - 5
 Displaying and setting real time integrate mode································ 5 - 5
6. SETTING OPERATION WITH SHIFT KEY······························································· 6 - 1
6.1 Setting Modes with SHIFT Key········································································· 6 - 2
6.2 Setting Mode Common Operations··································································· 6 - 3
6.3 Hold mold setting (HOLD-MD) ········································································· 6 - 4
 Display of hold mode setting mode ··················································· 6 - 4
 Hold mode setting ············································································· 6 - 4
6.4 Average setting mode (AVG-MD) ····································································· 6 - 5
 Display of average setting mode ······················································· 6 - 5
 Average setting ················································································· 6 - 5
6.5 Range display/setting (RNG-SET) ···································································· 6 - 6
 Range display mode·········································································· 6 - 6
 Range setting mode ·········································································· 6 - 6

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Paeg
6.6 Scaling setting (SCL-SET)················································································ 6 - 7
 Display of scaling setting··································································· 6 - 7
 Scaling setting··················································································· 6 - 7
6.7 Date and time setting (CLOCK) ········································································ 6 - 8
 Display of date and time setting ························································ 6 - 8
 Date and time setting ········································································ 6 - 8
7. REMOTE CONTROL FUNCTION············································································· 7 - 1
7.1 Setting GPIB / RS-232C ··················································································· 7 - 2
 Setting GPIB ····················································································· 7 - 2
 Setting RS-232C ··············································································· 7 - 3
 Canceling remote state ····································································· 7 - 3
7.2 GPIB interface ·································································································· 7 - 4
 GPIB interface functions ··································································· 7 - 4
 Device driver ····················································································· 7 - 4
 Outline of GPIB operations································································ 7 - 5
 Service Request (SRQ)····································································· 7 - 6
 Group Execute Trigger (GET) ··························································· 7 - 6
 Go To Local (GTL) ············································································ 7 - 6
 Local Lock Out (LLO) ········································································ 7 - 6
7.3 RS-232C interface ···························································································· 7 - 7
 RS-232C interface specifications ······················································ 7 - 7
 Connection of RS-232C cables ························································· 7 - 7
 Connection of RS-232C interface······················································ 7 - 8
 Outline of RS-232C operations ························································· 7 - 9
7.4 Program Codes ································································································ 7 - 10
 Program codes·················································································· 7 - 10
 Setting message ··············································································· 7 - 10
 Query message················································································· 7 - 11
7.5 Command List ·································································································· 7 - 12
7.6 Description of Individual Commands ································································ 7 - 14
7.7 Sample Programs····························································································· 7 - 20
 GPIB sample program······································································· 7 - 20
 RS-232C sample program································································· 7 - 21
 RS-232C supplementary description················································· 7 - 222721/2722

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Contents

Page
8. TROUBLESHOOTING AND MAINTENANCE ·························································· 8 - 1
8.1 Troubleshooting ································································································ 8 - 2
 Error display ······················································································ 8 - 2
 When the device appears to be a problem ········································ 8 - 2
8.2 Outline of Maintenance····················································································· 8 - 4
 Contents of maintenance work ·························································· 8 - 4
 Backup battery for internal clock ······················································· 8 - 4
8.3 Operation inspection························································································· 8 - 5
 Confirmation before operation inspection ·········································· 8 - 5
 Function check ·················································································· 8 - 5
8.4 Calibration Operation Method ··········································································· 8 - 6
 About calibration················································································ 8 - 6
 Check before calibration···································································· 8 - 6
 Display of calibration mode ······························································· 8 - 7
 Display of offset calibration mode······················································ 8 - 8
 Offset calibration setting method ······················································· 8 - 8
 Display of gain calibration mode························································ 8 - 9
 Gain calibration setting method ························································· 8 - 9
8.5 Performance Testing ························································································ 8 - 10
 Checking before performance testing················································ 8 - 10
 Required instrument ·········································································· 8 - 10
 Performance testing ·········································································· 8 - 10
9. SPECIFICATIONS ···································································································· 9 - 1
 Electrical rating·················································································· 9 - 1
 Environmental conditions ·································································· 9 - 5
 Power supply····················································································· 9 - 5
 Mechanical rating ·············································································· 9 - 5
 2721 External dimensions (Portable type)········································· 9 - 6
 2722 External dimensions (Rack mount type) ··································· 9 - 7
 2726 Micro-current probe /External dimensions ································ 9 - 7

82721/2722

Contents

FiguresPage
Figure 1-1

Block diagram························································································ 1 - 3

Figure 2-1

Line filter································································································ 2 - 4

Figure 3-1

Voltage and current cable connection diagram (1) ································ 3 - 7

Figure 3-2

Voltage and current cable connection diagram (2) ································ 3 - 7

Figure 3-3Single-phase voltage cable connection diagram ··································· 3 - 8

Figure 3-4

3-Phase 3-wire type voltage cable connection diagram (1) ··················· 3 - 8

Figure 3-5

3-Phase 3-wire type voltage cable connection diagram (2) ··················· 3 - 9

Figure 3-6

3-Phase 4-wire type voltage cable connection diagram ························ 3 - 9

Figure 3-7

Single-phase current cable connection diagram···································· 3 - 10

Figure 3-8

3-Phase 3-wire type current cable connection diagram························· 3 - 10

Figure 3-9

3-Phase 4-wire type current cable connection diagram························· 3 - 11

Figure 3-10 Voltage and current cable connection diagram ····································· 3 - 12
Figure 3-11 PT and CT connection diagram····························································· 3 - 12
Figure 3-12 3-Phase 3-wire type voltage and current cable connection diagram ····· 3 - 13
Figure 3-13 3-Phase 4-wire type voltage and current cable connection diagram ····· 3 - 14
Figure 4-1

START Input Circuit ·············································································· 4 - 4

Figure 4-2

TRIP Input Circuit ·················································································· 4 - 4

Figure 4-3

Reset Input Circuit ················································································· 4 - 4

Figure 7-1

Connection of RS-232C cables ····························································· 7 - 7

Figure 7-2

RS-232C Connector ·············································································· 7 - 82721/2722

9

Contents

Table
page
Table 1-1 Arithmetic expressions (1/2) ···································································· 1 - 5
Table 1-1 Arithmetic expressions (2/2) ···································································· 1 - 6
Table 2-1 2721/2722 configuration table ································································· 2 - 2
Table 2-2 2725 Input unit configuration table··························································· 2 - 2
Table 2-3 2726 Micro-current probe configuration table ·········································· 2 - 2
Table 3-1 Arithmetic expression of 3-phase 3-wire type wirring ······························ 3 - 13
Table 3-2 Arithmetic expression of 3-phase 4-wire type wirring ······························ 3 - 14
Table 4-1 START and TRIP Input Monitor Lamp Indication····································· 4 - 7
Table 7-1 GPIB interface functions·········································································· 7 - 4
Table 7-2 Device driver specifications ····································································· 7 - 4
Table 7-3 RS-232C Connector pin assignment ······················································· 7 - 8
Table 7-4 Command list (1/2) ·················································································· 7 - 12
Table 7-5 Command list (2/2) ·················································································· 7 - 13
Table 8-1 Error display ···························································································· 8 - 2
Table 8-2 Troubleshooting (1/2) ·············································································· 8 - 2
Table 8-3 Troubleshooting (2/2) ·············································································· 8 - 3

102721/2722

1. OVERVIEW

The “2712/2722 Power Multimeter” is a digital power multimeter capable of measuring
alternating current signals at high accuracy.
It supports the voltage 3 inputs and current 3 inputs. Also, it can support up to the voltage 4
inputs and current 4 inputs by adding an optional “2725 Input Unit”.
The measurement items are the line voltage, interphase voltage, current, electric power, power
factor, phase between voltage and current, interphase phase, frequency, integration, andcounter. Particularly, the phase difference can be measured between independent 4 inputs forboth voltage and current.
Two types are available; 2721 portable type with the input and output terminals arranged on
the side panels, and 2722 rack mount type with the I/O terminals arranged on the rear panel.

date 2010/1/13(#3)* “2722 Rack mount type” has been discontinued.

2721/2722

1-1

OUT LINE

1.1 Featuresz High accuracy
The voltage and current can be measured at high accuracy of ±(0.05% of displayed value +0.05% of range), the electric power at ±(0.1% of displayed value + 0.1% of range), and thephase at ±0.05°.
z Wide measurable range
The voltage can be measured from minimum 200mVrms to maximum 640Vrms.
The current can be measured directly from minimum 10mArms to maximum 25Arms. The
current can be measured from 200µA by connecting the “2726 Micro-current Probe”.
z Connector for external current probe
The connector to attach external current probe is furnished, so that optional Micro-current
Probe can be connected.
z Simultaneous display of 6 item measured data
The measured data of 6 items can be displayed simultaneously. Four different measurement
display settings can be stored by the display change key.
z Multi-phase (4 phases) inputs
This device supports the voltage 3 inputs and current 3 inputs. Also, it can support up to thevoltage 4 inputs and current 4 inputs by adding an optional “2725 Input Unit”. The “2725
Input Unit” should be chosen when placing an order.
z Multiple functions
In the connection for phase measurement, the line voltage can be measured withoutchanging the connection. The phase difference between any inputs can be measured. Also,
DC voltage and current can be measured in the DC measurement mode.
z Calculating function
The 3-phase voltage, current, electric power, and power factor in the 3-phase 3-wire type or
3-phase 4-wire type wiring can be calculated by arithmetic expressions.
z Integrating function
The integrated power, integrated reactive power, and integrated current can be measured,z Counter function
The counter for time measurement is provided. The measurement modes are “interval”, “oneshot”, and “train”. In the interval mode, the operation time and recovery time can bedisplayed at a time. The function that holds the measured data by means of a trip signal isbuilt in.
z Scaling function
The scaling common to all phases or individual to four phases can be set.
z Remote control interface
The GPIB and RS-232C are equipped as standard.

1-2

2721/2722

OUT LINE

1.2 Principle of Operation
 Functional block diagram
The voltage inputs are adjusted to the optimum level by the preamplifiers of which gain isvariable, and they are converted into digital values by the A/D converters, and transmitted by
the photocouplers, and then stored in the memories.
For the current inputs, the currents are converted into the voltages by the shunt resistors andentered in the preamplifiers, and then same processing as that of voltage inputs is executed.
For the frequency, the SYNC signal set by “SYNC” on the panel is used as a trigger signal toread the period by the counter and it is converted into the frequency to display. Also, thevoltage and current are read in synchronization with the SYNC signal.
The input waveform data that were read as mentioned above are calculated to obtain thevoltage, current, electric power, power factor, phase, etc. and the results are displayed on thepanel.
C P U & IN T E R F A C E B L O C K

IN P U T B L O C K
PHOTOCOUPLERSTART±
T R IP±

COUNTER1
CHAT1

COUNTER2

CPU

RESET
±

A /D C

16

±

AMP

A1
A /D C

16±

RAM

PHOTOCOUPLER

V1

PHOTOCOUPLER

ROM
AMP

E2PRO MAMP

V2

A /D C

16±

PHOTOCOUPLER

RTC

G P -IBG P IB I/F

R S -2 3 2C

16

16

A /D C16

A /D C

16

PHOTOCOUPLER

A /D C

16

±

AMP

A3
±

AMP

V0
±

AMP

A0
±

Figure 1-1

2721/2722

P R IN T E R I/F

D IS P L A Y&
KEY

C O UN TERPHOTOCOUPLER

A /D CPHOTOCOUPLER

AMP

V3

BUS

A /D C±PHOTOCOUPLER

A2

PHOTOCOUPLER

R S -2 3 2 C I/F

AMP

Block diagram

1-3

OUT LINE

 Arithmetic expressions of measurements
Arithmetic expressions of respective measurement items are shown below.
Here, Vni and Ani are the ith data when one period of the voltage input Vn and current input

An is divided by 511.
z AC voltage

Vn ( Vrms) =1 510 2∑Vni
511 i = 0z AC current

An (Arms) =1 510∑ Ani 2511 i = 0z Active power

Wn (W) =1 510∑ (Vni × Ani )511 i = 0z Phase difference (between A and B)510
 2π   2π  ∑∑
 Bi × cos 511 × i  Ai × cos 511 × i  − tan −1 i =0 
=0 
φ AB (deg) = tan −1 i510
510
π
π
2
2








∑
∑
 Bi × sin 511 × i  Ai × sin 511 × i  

i =0 
i =0 
510

z Line voltage mn

Vmn ( Vrms) = Vm + Vn − 2 × Vm × Vn cos(φ mn )22

z Apparent power

VAn ( VA ) = Vn × Anz Reactive power
2

Varn (var) = ± VAn − Wn2z Power factor

PFn =

1-4

Wn
VAn

2721/2722

OUT LINE

1.3 Description of Functions


Input function
The voltage inputs and current inputs are isolated from the case. Respective inputs are also
isolated from each other (test voltage AC 2kV).
A voltage range is 1V to 640V, and a current range is 0.04A to 24A.



Measuring function of micro-current (optional)
Micro-current of 200µA (range: 1mA - 10mA) can be measured by connecting the “2726
Micro-current Probe”.

Display function
The measurement and calculation results are displayed on six LED numeric displays (height
14.22mm, 5½ digits). Six data can be displayed at a time.
Also, since the function and element settings can be switched by the display change key, 24different function and element settings can be stored, and six of them can be displayed at a
time.



Calculating function
From the measured voltage, current, and active power, the following items can be calculated.
Wiring types are single-phase 2 wires, single-phase 3 wires, 3-phase 3 wires, or 3-phase 4
wires. Particularly, the line voltage and phase measurements can be done without changing
the connection. Also, the scaling value can be set for full voltage and full current or for each
input, and therefore the PT and CT can be used for any input. The scaling value is also
effective for the following arithmetic expressions besides voltage and current. If the phase ofcurrent lags behind the voltage, the reactive power is displayed with plus (+), and the power
factor is displayed with LAG in unit. If it leads from the voltage, the reactive power isdisplayed with minus (−), and the power factor is displayed with LEAD .
Table 1-1

Arithmetic expressions (1/2)

Single-phase 2 wires

3-phase 3 wires

V1 + V3
2
V12 ,V23 ,V31

3-phase 4 wires
V1 + V2 + V3
3
V12 , V23 , V31

Voltage (Vrms) V1 , V2 , V3VΣ =A1 , A2 , A3

AΣ =

AΣ =

WΣ = W1 + W3

WΣ = W1 + W2 + W3

Current (Arms)

A1 + A3
2
A1 , A2 , A3

Active power (W) W1 , W2 , W3

Apparent power VA1 = V1 × A1
(VA)

VAΣ =

VA2 = V2 × A2

A1 + A2 + A3
3
A1 , A2 , A3

3
(VA1 + VA3 ) VAΣ = VA1 + VA2 + VA32

VA3 = V3 × A3
2

2

2

2

Reactive power Var1 = ± VA1 − W1
(var)

VΣ =

Var2 = ± VA2 − W2

VarΣ = ± (Var1 + Var3 ) VarΣ = ±(Var1 + Var2 + Var3 )Var3 = ± VA3 2 − W3 2
2721/2722

1-5

OUT LINE

Table 1-2

Arithmetic expressions (1/2)

Single-phase 2 wires
W1
VA1
W
PF3 = ± 3
VA3

Power factor

PF1 = ±Phase

Vi − I j(deg)

Vi − V j

PF2 = ±

3-phase 3 wires
W2
VA2

Ii − I j

Integration

Wh1 , Wh2 , Wh3
Ah1 , Ah2 , Ah3
Varh1 ,Varh2 ,Varh3



W1
VA1
W
PF3 = ± 3
VA3

PF1 = ±W2
VA2
W
PFΣ = ± Σ
VAΣPF2 = ±

3-phase 4 wires
W1
VA1
W
PF3 = ± 3
VA3
PF1 = ±W2
VA2
W
PFΣ = ± Σ
VAΣPF2 = ±Vi − V j , Vi − I j
Ii − I j
V12 − V23 , V23 − V31
V31 − V12
V12 − I j , V23 − I j

Vi − V j ,Vi − I j
Ii − I j
V12 − V23 ,V23 − V31
V31 − V12
V12 − I j ,V23 − I j

V31 − I j
Wh1 , Wh2 , Wh3
Ah1 , Ah2 , Ah3

V31 − I j
Wh1 , Wh2 , Wh3
Ah1 , Ah2 , Ah3

Varh1 ,Varh2 ,Varh3
WhΣ , AhΣ ,VarhΣ

Varh1 ,Varh2 ,Varh3
WhΣ , AhΣ ,VarhΣ

Integrating function
Active power, current, and reactive power can be integrated. During the integration, theintegrated value and the integration elapse time can be displayed simultaneously. For the
integration measurement, three modes of manual integration, time integration, and actual
time integration are available.

Counter function (msec)
The operation time from the start input to the trip input can be measured. By switching thecounter mode, such high level time measuring function can be activated that the operation
time and recovery time are displayed simultaneously.
By the trip input, the measurement can be held.
The start/trip input setting and input state can be operated/monitored on the front panel.



Remote control function
In addition to GPIB, the RS-232C is equipped as standard. 24 data can be sent at a time.

Other functions
A portable type and a rack-mount type having different appearances are available.
For the (2721) portable type, the input and output terminals are arranged on the side panels,
enabling the input/output connections from the side. Also, the front panel cover is equipped
as standard for easy transportation.
For the (2722) rack-mount type, the input and output terminals are arranged on the rear
panel for easy connections in the rack, as well as safety use. The front cover is not equipped.
Electrical rating of both types is same.
* The (2722) rack-mount type has been discontinued.

1-6

2721/2722

2. PREPARATIONS BEFORE USE

This chapter describes the checking before using the “2712/2722 Power Multimeter”, generalprecautions on use, and installation method.
Before using the 2721/2722, be sure to read “Safety Precautions” located at the beginning of
this instruction manual, and the items on and after page 2-2 to check for safety.
Particularly, pay attention to the installation, which will affect the life, reliability, and safetyof the device.

date 2010/6/14(#127)

Also, this device weighs about 16 kg. Be careful when carrying the device.

2721/2722

2-1

PREPARATIONS BEFORE USE

2.1 Checking before Use Unpacking and repacking
After unpacking, first check if the product is damaged due to an accident during thetransportation. Though the product has been checked with care at the delivery, the customer
is asked to check particularly if any accessory is missing.
If the product is repacked for transportation, put the product with the pads durable to theweight in a cardboard box having sufficient strength and margin, and make packing so thatthe product is protected adequately.

 Standard configuration
The configuration of “2721/2722 ”is as listed below:
Table 2-1

2721/2722 configuration table

Main unit (2721/2722) ··········································································· 1 unit
Instruction manual················································································· 1 copy
Accessories: Front cover (2721 only) ·················································· 1 piece
Power cord (3 poles, 2m) ··············································· 1 piece
Power plug 3 poles – 2 poles adapter ···························· 1 piece
Fuse* (T1.6A/125V, ø5.2×20mm)··································· 1 piece* Fuse is built in the fuse holder.

 Input Unit configuration (for ELEMENT 0) [Choose this option
when placing an order, if necessary]
The configuration of “2725 Input Unit” is as listed below:
Table 2-22725 Input unit configuration table

Main unit (2725) ···················································································· 1 unit

 Micro-current probe configuration [Optional]
The configuration of “2726 Micro-current Probe” is as listed below:
Table 2-3

2726 Micro-current probe configuration table

Main unit (2726) ···················································································· 1 unit
Instruction manual················································································· 1 copy

2-2

2721/2722

PREPARATIONS BEFORE USE

2.2 Grounding and Power Supply
 Grounding！ WARNING
To prevent an electric shock accident, observe the following points:
Before making connection for measurement, be sure to connect the protective
ground terminal to the ground. The protective ground terminal of this device isa ground pin of 3-pole power plug or a ground terminal(2721 only).

Insert the power plug of the supplied power cord into the 3-pole power outlet
having a protective ground contact or pin.
When only the 2-pole power outlet is available, use the supplied 3 poles to 2
poles adapter. At this time, first connect a ground wire (green) of the adapter tothe ground terminal and then insert the power plug into the outlet.

 Power supply！ CAUTION
To protect the product from damage, beware of the following points:z Before connecting the power supply, confirm that the supply voltage settingof the device meets the voltage of the power outlet.
z The standard supply voltage setting made at the delivery of the device is
AC100V. Adjust the Voltage Selector switch to the operating voltage.
This product operates with commercial power supply.
y Supply voltage range: AC100/120/220/240V±10%, maximum AC250V

y Supply frequency range : 48 to 62Hz
y Power consumption: About 53VA for 2721/2722 alone, or about 62VA when 2725
is added

The rating of the supplied power cord is the power supply 125V and the withstand voltage
1250Vrms/1 minute. To use the device with the voltage exceeding AC125V, the power cord
must be changed. Please contact us.

！ CAUTION
Do not change over the Voltage Selector switch with the power cord inserted
into the outlet. The product may be damaged.

2721/2722

2-3

PREPARATIONS BEFORE USE

 Line filter
This device uses a line filter of the circuit shown below.
The leakage current is maximum 0.5mArms at 250V 62Hz. Therefore you may get shocked if
touching a metallic part of the device.
For the operator’s safety, be sure to take grounding.
Fuse

To switch andpower transformer

Power supply input
connector

Case or groundterminal

Figure 2-1

Line filter Power fuse
！ WARNING
To prevent a fire, do not use a fuse other than the rated one.
Before replacing the fuse, be sure to disconnect the power cord.
The rated power fuse of this device is as follows:y Fuse capacity : 1.6A at AC100/120V
0.8A at AC220/240V
y Fuse type: Time-lag type, rated voltage 250V, φ5.2×20mm

Replace the fuse meeting the supply voltage. As standard, the device is delivered with 1.6A
fuse. When 0.8A fuse is necessary, please contact NF Corporation.

2-4

2721/2722

PREPARATIONS BEFORE USE

2.3 Installation
 Precautions！ CAUTION
To protect the product from damage, beware of the following points:z The device is forcibly cooled by air using a fan. When you find that the fan
has stopped, turn off the power switch immediately and please contact NF
Corporation or one of our representatives. Using the product with the fan
stopped may increase the damage, thus making the repair impossible.
z The intake ports and exhaust ports are provided at the rear, side, and bottomof the device. Install the device, leaving a space between rear panel / sidepanels and wall.

 Installation conditions
Install this device at a place that fulfills the following temperature and humidity conditions.
Also, use the device free from condensation.
y Operation guaranteed : 0 to 40°C, 20 to 80%RH (Temperature range to guarantee
accuracy: 23±5°C)
y Storage: −10 to 50°C, No condensation

Do not install the device in locations such as:z location with direct sunlight or with a nearby source of heatz location with significant amounts of dust, salt, metallic powders
z location with significant amounts of corrosive gases, vapor, sootz Place where flammable gas or steam is present.
z location exposed to excessive vibration
z location close to a strong magnetic or electromagnetic field source
z location close to a pulsing noise source Handling of the panel and case
When the case/panel surface needs cleaning, wipe with a soft cloth. To remove persistentcontamination, wipe with a soft cloth soaked with neutral detergent and wrung out.
Do not use any organic solvents like thinner or benzene, or any chemical cleaning cloth, as
they may cause the surface coating to deteriorate or come off.

2721/2722

2-5

PREPARATIONS BEFORE USE

MEMO

2-6

2721/2722

3. BASIC OPERATIONSThis chapter describes basic operating methods of the “2721/2722 Power Multimeter”.
Descriptions of basic operations include “names and operations of components on front panel
and side/rear panel (side panel for 2721, or rear panel for 2722)”, “measurement condition
setting”, “description and operation of Display A, B, C, D, E, F”, “measurement of voltage,current, electric power, power factor, and phase difference”, and “other measurements”.
Detailed descriptions are given in the panel explanatory drawings on the following pages
which should be referred to.
For an operating method of the counter function, see “4. Counter Function”, and for an
operating method of the integrating function, see “5. Integrating Function”.

date 2010/1/20(#6)

For the detailed settings of measurement, see “6. Setting Operation with SHIFT Key”.

2721/2722

3-1

BASIC OPERATIONS

Description of displayed characters
Alphanumeric characters displayed in the Displays A, B, C, D, E, and F (7 segments) are as
follows.
Alphanumeric characters are displayed as the settings of measurement conditions, countermode, or present time, etc. Though they are displayed as straightforward as possible, somecharacters cannot be expressed. Accordingly, refer to the following list.

z Numbers

:0

:1

:2

:3

:4

:5

:6

:7

:8

:9

:A

: B(b):C: D(d)

:E

:F

:G

:H

: I(i)

:J

:K

:L

:M

:N

:O

:P

:Q

:R

:S

: T(t)

:U

:V

:W

:X

:Y

z Alphabets:Zz Others: _ (under bar)

3-2

: - (hyphen)

2721/2722

BASIC OPERATIONS■ Front panel
When FUNCTION _V_ and ELEMENT _1_, _2_ light up,
the line voltage calculated value of V12 is displayed.

V
Voltage measurement
A
Current measurement
W Active power measurement
VA Apparent power measurement
Var Reactive power measurement
PF Power factor measurement
deg Phase measurementz Phase display
When _deg_, _V_ and _1_ light up, the phase difference
between SYNC signal and V1 is displayed.
When _deg_, _V_, _A_ and _1_ light up, the phasedifference between V1 and A1 is displayed.

Input state display
PEAK OVERNF ELECTRONICINSTRUMENTS

NF

Lights up when excess signal is input.

2721

PEAK
OVER

GPIB state display
SRQ
Lights up when serial request is output.

V

1
2
3
0
Σ

Element 1
Element 2
Element 3
Element 0
Calculation result

A

W

VA

Var

PF

Function selection anddisplay
FUNCTION F(p.3-19)

CNTR
V/A
V/3A
Vsin
AB

Hz
Wh
Ah
Varh
CD

Counter measurement
Impedance V/A
Impedance V/√3A
Impedance V/2Asinφ
Phase difference between

Sets the SYNC signal.
The lamp of selected phase lights up.

Integrating function keys (P.5-2)

Frequency measurement
Integrated active power
Integrated current
Integrated reactive power
Phase difference between

Integrating function keys.

START
Start the integration.

STOP
Stops the integration.

RESET

POWER
MULTIMETERFUNCTION

deg

V

A

W

VA

Var

PF

SYNC

FUNCTION

deg

V

A

W

VA

Var

PF

POWER

V1

deg

SHIFT + INT-MD(p.5-4)

V0

V0

Activates the integration setting mode.

A1

SHIFT + CLOCK(p.6-8)

A2

Activates the date and time setting
mode.

ELEMENT

A

1

2

3

0

Δ

B

Σ

Δ

ELEMENT
1

2

3

0

ELEMENT

C

Σ

1

2

3

0

Δ

Σ

A3

FUNCTION
V

GPIB
SRQ

A

W

VA

Var

PF

FUNCTION

deg

V

A

CNTR V/A

V/3A Vsin A-B

V

A

Hz

Wh

FUNCTION

A0

Varh C-DLINE

AhHarmonic measurement key

RMT
ERROR

RNG

NO
TRIG

Lights up when an input signal varies and arange is indefinite.

RNG

ELEMENT

D

1

1

2

3

2

3

0

MODE
AC

STORE/RECALL

STORE/RECALL 1 , 2 , 3 , 4

Δ
1

2

3

0

ELEMENTFΣCOUNTERWIRING
1Φ2W 1Φ3W

4Δ

ELEMENT

E

Σ

1

2

3

0

Σ

INTEGRATERESETCONT START

B-M

CNTMD

VOLT

M-B

CHAT

CONT

START

STOP

RESET

TIME

HARM

INT-MD

CLOCK

HRM-MD

AUTO

SCAL

D/A

Inactive (To be set as an option)Δ

RS-232C SHIFTINTERVAL

DC

3Φ3W

3Φ4W

Four measurement item settings can be
stored.

TRIP

B-M

HOLD

AVRG

ONE SHOT

PRINT

ENTER

LOCAL

●
CAT-SET

VOLT

M-B

HLD-MD

AVG-MD

RNG-MD

SCL-SET

DA-SET

PRT-MD

Activates the RS-232C setting mode.

Switches the measurement mode to AC mode.
The r.m.s. value is displayed.

Auto range setting on/off key
AUTO(p.3-15)

DC

is set for ELEMENT, the calculation

result for the displayed and set wiring isdisplayed.

Counter measurement condition setting keys (p.4-5)
INTERVAL / ONE SHOT
Selects the interval mode or one shot mode.
When the lamp lights up, the interval mode is selected.

CHAT

Turns on/off the average function.

Turns on/off the chattering eliminating function.

SHIFT + AVG-MD(p.6-5)

CONT / VOLT

Activates the average setting mode.

When a counter setting key is turned on (lampON), the function of red characters (upper sideof key) is active, or when it is turned off (lampOFF), the function of black characters (lower
side of key) is active.

2721/2722

Switches the operation mode of input.
When the lamp lights up, the operation mode is Break (contact
open/voltage present) → Make (contact closed/voltage 0V). Whenthe lamp is off, the operation mode is Make → Break.

START / TRIP lamp
Indicates the input state.
They light up when the input is active (if B-M, contact
closed/voltage 0V).

SHIFT + GPIB

Activates the range display/setting mode.

Reset key

B-M / M-B

Switches the mode from remote to local.

SHIFT + RNG-MD(p.6-6)

Average function on/off key
AVRG(p.3-15)

RESET

Switches the input format to contact or voltage. When the lamp
lights up, the contact input is selected.

Note:

GPIB / LOCAL key (p.7-2)
LOCAL

Turns on/off the auto range function.

Switches the measurement mode to DC mode.

If Σ

Press this key before pressing a setting
mode key. The function indicated withblue characters on the lower side of key
becomes active.

RS-232C setting key (p.7-3)
RS-232CAC

Sets the wiring conditions of calculating
function.

SHIFT key
SHIFT

GPIB

Measurement mode setting keys (p.315)

Wiring type setting keys (p.3-15)
1φ2W, 1φ3W, 3φ3W, 3φ4W

Displays the integrated time.

V3

A0

Display setting and recall keys (p.3-19)

TIME

V3

A3

Lights up when SYNC signal is not input.

Resets the integrated result.

V2

A2

Lights up in the remote state.

ELEMENT (p.3-19)

Function selection anddisplay
FUNCTION E(p.3-19)

V2

A1

RMT

Element selection and display

FUNCTION

V1

Error display
NO TRIGSYNC signal setting and display(p.3-15)

Function selection and display
FUNCTION A, B, C, D (p.3-19)z Line voltage display

Hold function on/off key
HOLD(p.3-15)
Holds the display.
Since this key only cancels the reading of waveform, if
FUNCTION/ELEMENT is changed, the measured values ofanother parameters can be displayed even in the Holdstate.

Activates the GPIB setting mode.

Analog output key
Inactive(To be set as an option)

Scaling function on/off key
SCAL(p.3-15)

Cursor keys (p.6-3)
Use these keys in respective setting
modes.

PRINT key
Inactive (To be set as an option)

SHIFT + ENTER(p.8-6)
Activates the calibration setting mode.

Turns on/off the scaling function.

SHIFT + SCL-SET(p.6-7)
Activates the scaling setting mode.

SHIFT + HLD-MD(p.6-4)
Activates the hold mode setting mode.

3-3

BASIC OPERATIONS■ Side/Rear panel2725 input unit
[Option when placing an order]

2721 right side panel

2721 left side panel
COUNTERELEMENT 1

STARTP_+200VMAX

±

_
+85V

ELEMENT 2

EXIT-PROBEINPUT 2V/FS

V

EXIT-PROBEINPUT 2V/FS

V

650Vrms MAX

EXIT-PROBEINPUT 2V/FS

_
+920V

RS-232C

PRINTERANALOG OUTPUT

650Vrms MAX

±

±
_
+920V

_
+920V

GPIB

EXIT-PROBEINPUT 2V/FS

V

650Vrms MAX

±
_
+920V

ELEMENT 0

V

650Vrms MAX

±
_
+920V

TRIP

P

ELEMENT 3

_
+920V

_
+920V

_
+920V

_+200VMAX

A

±

A

A

A

_
+85V

RESET
25Arms MAX+

25Arms MAX

25Arms MAX～ LINE 48-62Hz

25Arms MAX-

VOLTAGE SELECTOR!

5V MAX

220V

±

_
+920V

±

±

_
+920V

±

_
+920V

120V

Use only white
250Vfuse

_
+920V

100V

Employer uniquement
avec

Counter input unit (p.4-4)
START
Input the counter start signal.

TRIP

Voltage and current input unit (p.3-7)
V,±

RESET

EXT-PROBE

Supply voltage setting switch (p.2-3)
VOLTAGE SELECTOR
100V, 120V, 220V, 240V

3-pin connector with a protective groundterminal.
The ground terminal is separately provided
on the side of power connector.

A,±
Current input terminals

NF CORPORATION MADE IN JAPANPower connector (p.2-3)~ LINE 48-62Hz

Voltage input terminals

Input the counter trip (stop) signal.
Input the counter data external reset signal.
For the input of start and trip signals,
contact input or voltage input is selectablewith the CONT/VOLT key on the front panel.
The operation mode of input is also
selectable with the B-M/M-B key.
The reset signal input can be controlled on
the TTL level where the counter display canbe reset at 0V.

FUSE

100V,120V T1.6A/250V
220V,240V T0.8A/250V

240V

External current probe connector“2726 Micro-current Probe”, etc. can be connected.

Set the switch meeting the supply voltage
used.

Power fuse holder (p.2-4)
100V/120V T1.6A/250V
220V/240V T0.8A/250V

Selector switch
Selects the current input. The lower position makes active thecurrent input terminal, while the upper position makes active
the external current probe connector.

Use the fuse meeting the supply voltage
used. A spare fuse is contained in the holder.

Note: Do not connect to the current input terminals (A, ±)when the external current probe is used.

2725 input unit
[Option when placing an order]

RS-232C connector (p.7-8)
Connect the RS-232C cable when making
communication via RS-232C interface.

2722 rear panel
COUNTERELEMENT 1

START

ELEMENT 2

EXT PROBEINPUT 2V/FS

P_+200VMAX

±

_
+85V

V
650Vrms MAX

P

_
+920V

±
_
+920V

_
+920V

RS-232C

GPIB connector (p.7-4)

650Vrms MAX

±
_
+920V

INPUT 2V/FS

V

650Vrms MAX±

ANALOG OUTPUT

EXT PROBEINPUT 2V/FS

V

650Vrms MAX±

ELEMENT 0

EXT PROBEINPUT 2V/FS

V

_
+920V

TRIP

ELEMENT 3

EXT PROBE

Connect the GPIB cable when making
communication via GPIB interface.

GPIB
_
+920V

_
+920V

_
+920V

PRINTER_+200VMAX

A

±

A

A

A

_
+85V

RESET

～ LINE 48-62Hz

25Arms MAX+

25Arms MAX

25Arms MAX

100V,120V/T1.6A/250V
220V,240V/T0.8A/250V

25Arms MAX

VOLTAGE SELECTOR
5V MAX

-

±

_
+920V

±

_
+920V

±

_
+920V

±

_
+920V

220V
240V
120V
100V

2721/2722

Use only white 250Vfuse
Employer uniquement
avec
unfusible de 250V

FUSE

3-4

BASIC OPERATIONS

3.1 Operation at Power ON
 Display when the power is turned on
When the power switch is turned on, the test program starts to conduct a test. The contents ofa test are RAM check, ROM check, etc.
At the power ON, the opening message as shown below is displayed.
(1)

9S.N
A

B

C

D

E

F

The Display A shows the model name “2721” or “2722”.
The Display B shows a program version. As the program version is subject to change, actual
version shown on your Display may be different from this description.
The Display C shows the last 6 digits of a serial number of the product. The 6-digit number iscomposed of 7-segment 5 digits (99999) + 1-digit unit indication (9).

Ð
(2)
A

B

C
adrs

D

E

dlmt
F

The Display E shows GPIB address setting, and Display F shows GPIB delimiter setting(factory setting: 7 adrs, CRLF).

Ð
(3)

bps
A

B

C

stop
D

prty
E

dlmt
F

The Display C shows RS-232C baud rate setting, Display D shows stop bit setting, Display Eshows parity setting, and Display F shows delimiter setting (factory setting: 4800bps, 1 stop,
NON, CR-LF).

Ð
(3)
A

B

C

D

E

F

The internal AD converter is calibrated. The Display F counts down from 100 to 0.

Ð
To measurement
operation

Note
The warm-up time until all specifications are satisfied is about 30 minutes.

2721/2722

3-5

BASIC OPERATIONSz Display in case of RAM/ROM error
When RAM/ROM error occurred, the display of (1) on previous page is as shown below.
9SN.
A

B

C
Csum

D

E

F

The Display D shows an error number (Error 2 in above case), Display E shows checksum dataof ROM, and Display F shows a comment that requires a check. When an error is displayed,
please contact NF Corporation one of our representatives.

 Display/setting of date and time setting mode
When the power switch is turned on, the “date and time setting mode” is activated unless theinternal clock has been set.
NOW>
A

00s

1996

B

C

E

F

SET>

1996

D

• Display A: “CLoCk”

Indicates the date and time setting mode.
Indicates that Displays B and C are internal time andNOW>internal date.
Indicates that Displays E and F are set time and set date.

SET>• Display B: “12-00 00s”

Internal time (12H00M00S)• Display C: “07-15 1996”

Internal date (July 15, 1996)• Display D: “12-00 00s”

Set time (12H00M00S)
Initial value is same as internal time on Display C.

• Display E: “07-15 1996”

Set date (July 15, 1996)
Initial value is same as internal date on Display C.
Year changes like “1996↔1997↔1998↔1999↔2000↔ ....”.

A setting method is as follows:Î Year “96” on Display F• Cursor initial valueÎ Year month day and hour minute are incremented or• Setting method
decremented by _▲_ , _▼_ keys.
TIME• Setting canceling method

SHIFT

or

Î

TIME

+

CLOCK

NOW>
A

CLOCK

52s
B

1996
C

SET>
D

1996
E

[Example] To change the day 15 to day 21, press▲
day “15” and press

3-6

▲

F

key to move the cursor (blinking) to

key 6 times.

2721/2722

BASIC OPERATIONS

3.2 Connecting Voltage and Current Cables
 Precautions when connecting voltage and current cables
Connect the voltage and current to be measured to the voltage input terminals “V, ±” andcurrent input terminals “A, ±” of each element panel.
For both voltage and current, the “±” terminal is the reference of the phase. Take care not toconnect the cables reversely in the measurements of phase difference, active power, reactive
power, and power factor that are affected by the phase.
The input impedance of voltage input terminal is about 1MΩ, and the impedance of current
input terminal is about 5mΩ (contact resistance of the terminal is not included). To measure
the electric power precisely, perform the wiring so that these influences are minimized.
Usually, in a case with small voltage and large current, perform the wiring as shown in“Figure 3-1 Voltage and Current Cable Connection Diagram (1)” to eliminate the influence ofvoltage drop due to the current sensing resistor. Also, in a case with large voltage and small
current, perform the wiring as shown in “Figure 3-2 Voltage and Current Cable Connection
Diagram (2)” to minimize the influence of voltage input impedance.

LOAD

SOURCE ～

A

V

±

±

A: Large current

Figure 3-1

V: Small voltage

Voltage and current cable connection diagram (1)LOAD

SOURCE ～A±
A: Small current

Figure 3-2

V

Note

±

V: Large voltage

Note: In the wiring in the left figure, theself power consumption of thisproduct can be obtained by reconnecting the “±” terminal ofvoltage to the “±” terminal of
current. True load power can beobtained by subtracting this value
from the measured power.

Voltage and current cable connection diagram (2)Note
The voltage and current measurement display does not become “0.0000” because of
the residual noise or offset voltage even if the SYNC signal is set to LINE in thevoltage input short-circuit and current input open states.
The device will be normal if the voltage is around several mV and the current aroundseveral 100µA after the warm-up.

2721/2722

3-7

BASIC OPERATIONS Connection for voltage measurement
Connect the voltage to be measured to the voltage input terminals “V, ±” of the element panel.
The “±” terminal is the reference of the phase. Take care not to connect the cables reversely inthe measurement of phase difference.
The FUNCTION and ELEMENT settings and the contents of display are shown as a panelsetting example. For the voltage measurement, the WIRING setting of a wiring type is notapplicable.

z Voltage cable connection method in single-phase voltage measurement
FUNCTIONV

ELEMENT

Contents of display

1 / 2 / 3 /( 0 ) Voltage of ELEMENT 1/2/3/(0)LOAD

SOURCE ～V±
V: Voltage

Figure 3-3Single-phase voltage cable connection diagramz Voltage cable connection method in 3-phase 3-wire type line voltage measurement
FUNCTIONV

ELEMENT

Contents of display

1

Voltage of ELEMENT 1 (RS line voltage)

2

Voltage of ELEMENT 2 (ST line voltage)

1 + 2 +●

Line voltage of ELEMENT 1-2 (RT line voltage)

R
SOURCE

LOAD

～

～
～

S
T

V
±

V

V2

ELEMENT 2

Figure 3-4

3-8

±

V1

ELEMENT 1

3-Phase 3-wire type voltage cable connection diagram (1)2721/2722

BASIC OPERATIONSz Voltage cable connection method in 3-phase 3-wire type phase voltage measurement(to ground)
FUNCTIONELEMENT

V

Contents of display

1

Voltage of ELEMENT 1 (R phase voltage)

2

Voltage of ELEMENT 2 (S phase voltage)

3

Voltage of ELEMENT 3 (T phase voltage)

1 + 2 +●

Line voltage of ELEMENT 1-2 (RS line voltage)

2 + 3 +●

Line voltage of ELEMENT 2-3 (ST line voltage)

3 + 1 +●

Line voltage of ELEMENT 3-1 (TR line voltage)

R
SOURCE

LOAD

～

～
S

～

T
Note

Figure 3-5

V

V

V

±

±

±

ELEMENT 1

ELEMENT 2

ELEMENT 3

Note: This connection
method is formeasuring thevoltage to ground. If
either phase of RST
is grounded, thevoltage to thegrounded phase is

3-Phase 3-wire type voltage cable connection diagram (2)z Voltage cable connection method in 3-phase 4-wire type wiring
FUNCTIONELEMENT

V

V

Contents of display

1

Voltage of ELEMENT 1 (R phase voltage)

2

Voltage of ELEMENT 2 (S phase voltage)

3

Voltage of ELEMENT 3 (T phase voltage)

1 + 2 +●

Line voltage of ELEMENT 1-2 (RS line voltage)

2 + 3 +●

Line voltage of ELEMENT 2-3 (ST line voltage)

3 + 1 +●

Line voltage of ELEMENT 3-1 (TR line voltage)

R
SOURCE

LOAD

～

～

～

S
T
N

Figure 3-6

2721/2722

V

V

V

±

±

±

ELEMENT 3

ELEMENT 2

ELEMENT 1

3-Phase 4-wire type voltage cable connection diagram

3-9

BASIC OPERATIONS Connection for current measurement
Connect the current to be measured to the current input terminals “A, ±” of the element panel.
The “±” terminal is the reference of the phase. Take care not to connect the cables reversely inthe measurement of phase difference.
The FUNCTION and ELEMENT settings and the contents of display are shown as a panelsetting example. For the current measurement, the WIRING setting of a wiring type is notapplicable.

z Current cable connection method in single-phase
FUNCTIONELEMENTA

Contents of display

1 / 2 / 3 /( 0 ) Current of ELEMENT 1/2/3/(0)LOAD

SOURCE ～A±
A: Current

Figure 3-7

Single-phase current cable connection diagramz Current cable connection method in 3-phase 3-wire type
FUNCTIONELEMENTA

Contents of display

1

Current of ELEMENT 1 (R phase current)2

Current of ELEMENT 2 (S phase current)3

Current of ELEMENT 3 (T phase current)

R
SOURCE

LOAD

～

～
～

S
T

A

A

A

±

±

±

ELEMENT 3

Figure 3-8

3 - 10ELEMENT 2 ELEMENT 1

3-Phase 3-wire type current cable connection diagram

2721/2722

BASIC OPERATIONSz Current cable connection method in 3-phase 4-wire type
FUNCTIONELEMENTA

Contents of display

1

Current of ELEMENT 1 (R phase current)2

Current of ELEMENT 2 (S phase current)3

Current of ELEMENT 3 (Tphase current)

0

Note

Current of ELEMENT 0 (N phase current)
R

SOURCE

LOAD

～

～

～

S
T
N

Figure 3-92721/2722

Note
A

A

A

A

±

±

±

±

ELEMENT 3

ELEMENT 2

ELEMENT 1

ELEMENT 0

Note: Effective if the“Input Unit 2725”
is installed in
ELEMENT 0.

3-Phase 4-wire type current cable connection diagram

3 - 11BASIC OPERATIONS Connection for power measurementz Power measurement in single-phase 2-wire type wiring
If both voltage and current are in the specification range, select one of three pairs of input
voltage and current terminals, and perform the wiring as shown in “Figure 3-10 Voltage andcurrent cable connection diagram”.
In this case, when three pairs are connected to the separate SOURCES, if the frequency issame, all inputs can be measured, but if the frequency is different, only the input selected with
SYNC is measured normally.
The maximum measurement range is the voltage input 650Vrms, and the current input
25Arms. Accordingly when larger voltage or current is measured, connect an externalpotential transformer (PT) or external current transformer (CT) as shown in “Figure 3-11 PT
and CT connection diagram”.
Instead of external current transformer, the clamp-on probe (20A, 200A) can be connected tothe external current probe input.

LOAD

SOURCE ～

A

V

±

±

Use voltage and current input
terminals of same ELEMENT

Figure 3-10

Voltage and current cable connection diagram

LOAD

SOURCE ～

L

V
PT

CT
l

v
A

Figure 3-11

3 - 12±V±

PT and CT connection diagram

2721/2722

BASIC OPERATIONSz Power measurement in 3-phase 3-wire type wiring
To measure the electric power (balanced load) in the 3-phase 3-wire type wiring (symmetric 3phase AC), perform the wiring of 2 pairs of voltage and current input terminals as shown in“Figure 3-12 3-Phase 3-wire type voltage and current cable connection diagram”.
In this case, connect to V1, A1 and V3, A3. In other connections, the electric power cannot bemeasured normally.
By setting the WIRING key to “3φ3W” type wiring and the ELEMENT to _∑_, the calculation
result shown in “Table 3-1 Arithmetic expression of 3-phase 3-wire type wiring” is displayed.
WIRING
3φ3W

FUNCTIONELEMENT

Contents of display

Arithmetic expression

3-phase voltage

VΣ=(V1+V3)/2A

3-phase current

AΣ=(A1+A3)/2W

3-phase active power

WΣ=W1+W3

VA

3-phase apparent power

VAΣ=

Var

3-phase reactive power

VarΣ=Var1+Var3

PF

3-phase power factor

PFΣ=WΣ/VAΣ

V∑

3
×(VA1+ VA3)2

R
SOURCE

LOAD

～

～
S

～

T
A

±

V

A3

±

ELEMENT 3

Figure 3-12

A

V3

±

V

A1

±

V1

ELEMENT 1

3-Phase 3-wire type voltage and current cable connection diagram

Table 3-1

Arithmetic expression of 3-phase 3-wire type wirring
WIRING

FUNC,ELMT

Arithmetic expression of 3φ3W

A , ∑V1 + V3
2
A + A3AΣ = 1
2

W , ∑WΣ = W1 + W3

V , ∑VA *, ∑

Var *, ∑PF *, ∑

VΣ =

VAΣ=

3
×(VA1+VA3)
2

VarΣ=Var1+Var3
PFΣ =

WΣ
VA Σ

Note*: This arithmetic expression is established only when three phases arebalanced sine waves.

2721/2722

3 - 13

BASIC OPERATIONSz Power measurement in 3-phase 4-wire type wiring
To measure the electric power (balanced load) in the 3-phase 4-wire type wiring (symmetric 3phase AC), perform the wiring of 3 pairs of voltage and current input terminals as shown in“Figure 3-13 3-Phase 4-wire type voltage and current cable connection diagram”.
By setting the WIRING key to “3φ4W” type wiring and the ELEMENT to _∑_, the calculation
result shown in “Table 3-2 Arithmetic expression of 3-phase 4-wire type wiring” is displayed.
WIRINGFUNCTION

3φ4W

ELEMENT

Contents of display

Arithmetic expression

3-phase voltage

VΣ=(V1+V2+V3)/3A

3-phase current

AΣ=(A1+A2+A3)/3W

3-phase active power

WΣ=W1+W2+W3

VA

3-phase apparent power

VAΣ=VA1+VA2+VA3

Var

3-phase reactive power

VarΣ=Var1+Var2+Var3

PF

3-phase power factor

PFΣ=WΣ/VAΣ

V∑

R
SOURCE

LOAD

～

～

～

S
T
N
A

V

±

±
A3
ELEMENT 3

Figure 3-13

A

V3

V

A

±

±
A2
ELEMENT 2

V2

V

±

±
A1
ELEMENT 1

V1

3-Phase 4-wire type voltage and current cable connection diagram

Table 3-2

Arithmetic expression of 3-phase 4-wire type wirring
WIRING

FUNC,ELMT

Arithmetic expression of 3φ4W

V , ∑

VΣ =

V1 + V2 + V3
3

A , ∑

AΣ =

A1 + A 2 + A 3
3

W , ∑

WΣ = W1 + W2 + W3

VA *, ∑

VAΣ=VA1+VA2+VA3

Var *, ∑VarΣ=Var1+Var2+Var3

PF *, ∑

PFΣ =

WΣ
VA Σ

Note*: This arithmetic expression is established only when three phases arebalanced sine waves.

3 - 142721/2722

BASIC OPERATIONS

3.3 Setting Measurement Conditions
This section describes the setting of measurement conditions.
As the measurement conditions, the SYNC signal, measurement mode, wiring type, holdfunction, average function, auto range setting, and scaling function can be set.
Since the setting of measurement conditions puts large influence on the measurement, if thefactory settings are changed, the descriptions should be read carefully in advance.
SYNC
SYNC signal setting keys
NF ELECTRONICINSTRUMENTS

NF

2721

PEAK
OVER

POWER MULTIMETERFUNCTION

V1

V

A

W

VA

Var

PF

FUNCTION

deg

V

A

W

VA

Var

PF

SYNC

FUNCTION

deg

V

A

W

VA

Var

PF

POWER

V1

deg

V2

V2

V3

V3
V0
A1

A

A2

Δ

ELEMENT
1

2

3

W

VA

Var

1

2

3

0

B

Σ

Δ

ELEMENT
1

2

3

CNTR

V/A

V/3A

1

2

3

0

C

Σ

1

2

3

Hz

Wh

Ah

1

2

3

V0

Δ

ELEMENT

A1
A2

Σ

0

A3

A3

FUNCTION

A0
V

GPIB
SRQ

A

PF

FUNCTION

deg

V

A

Vsin

FUNCTION

A-B

V

A

Varh

A0

C-D

LIN
E

RMT
ERROR

NO
TRIG

RNG

2

3

0

MODE
AC

STORE/RECALL
1Δ

ELEMENTD

Δ

ELEMENTEΣ

0

WIRING
1Φ2W
1Φ3W

4

RESET

CONT

START

Δ

ELEMENTFΣCOUNTER0Σ

INTEGRATE
START

STOP

B-M

HOLD

AVRG

M-B

HLD-MD

AVG-MD

B-M

RESET

RS-232C

TIME

HARM

INT-MD

CLOCK

HRM-MD

AUTO

SCAL

D/A

PRINT

RNG-MD

SCL-SET

DA-SET

PRT-MDSHIFTINTERVAL

DC

3Φ3W

CNTMD

VOLT

CHAT

CONT

CAT-SET

VOLT

3Φ4W

M-B

TRIP

ONE SHOT

ENTER

LOCAL

●
GPIB

MODE AC, DC
Measurementmode setting keys

HOLD
Hold function on/off key

SCAL
Scaling function on/off key

1φ2W,1φ3W,3φ3W,3φ4W
Wiring type setting keys

AVRG
Average function on/off key

AUTO
Auto range setting on/off key

 Initializing the settings
To initialize respective set values to the factory settings, turn off the power switch once, andthen turn on the power switch while pressing the LOCAL key. For the LOCAL key, press it
continuously until all displays light up.

date 2009/12/21(#292)

Table 3·3-1

Initializing the settings (1/2)

Panel setting

Key operation

Initial set values

Displayed items

STORE/RECALL _1_

V1, A1, W1, Var1, A-B, Hz

STORE/RECALL _2_

W1, W2, W3, WΣ, V/A1, Hz

STORE/RECALL _3_

degV1,degV2,degV3,degV12,V/√
3A1,HzSTORE/RECALL _4_

degA1,degA2,degA3,degA12,V/sin1,Hz

SYNC signal

SYNC

LINE

Measurement mode

MODE

AC

Wiring type

WIRING

1φ2W

Counter

INTERVAL/ONE SHOT

INTERVAL(OFF)

CHAT

OFF

CONT/VOLT,B-M/M-B

VOLT(OFF), M-B(OFF)

Display hold

HOLD

OFF

Measurement averagefunction

AVRG

ON

Scaling function

SCAL

OFF

2721/2722

3 - 15

BASIC OPERATIONS

Table 3·3-2

Initializing the settings (2/2)

Panel setting

Key operation

Initial set values

Counter mode

Interval mode

Single mode (SinGL)

One Shot mode

One Shot mode (onESt)

External reset function

OFF

Trip input threshold

2.5V(trP2.5±)

Chattering

Time setting

100ms

Measurement condition
settingPhase display

0 to 360deg

External hold function

OFF

Moving average count1 timeWavenumber average count8 times

Mode setting

All setting (ALL)

Scaling value

1.0000Integrate mode

Manual mode (norML)

Average setting
Scaling setting
Integration setting Setting SYNC signal

SYNC

,

Be sure to set the SYNC signal when the measurement mode is AC.
As the SYNC signal, set either one of V1, V2, V3, V0, A1, A2, A3, A0, and LINE. To select the
SYNC signal, use,

keys. The lamp of the selected signal in the SYNC display block

lights up. The V0 and A0 do not light up if the “2725 Input Unit (for ELEMENT 0)” is notinstalled.

Note
The minimum level of SYNC input signal is about 0.1V for voltage and about 4mA
for current.
When a signal smaller than the minimum level is measured, set the SYNC signal tothe input signal larger than the minimum level of SYNC input signal which issynchronized with the signal to be measured.
ince the larger SYNC signal level enables the measurement at higher accuracy, set
the input signal as large as possible.

Note
When measuring an input signal not synchronized with the power supply, exact
measurement will not be performed if the SYNC signal is set to LINE.
Be sure to set the SYNC signal to the input signal which is synchronized with thesignal to be measured.

3 - 162721/2722

BASIC OPERATIONSAC Setting measurement mode

DC

,

MODE

Select the mode to measure the voltage, current, or electric power. The AC or DC mode isselectable by pressing the MODE AC key or DC key on the front panel. The lamp on theselected key lights up.

z AC
AC component and DC component of the input voltage and current are measured, and“true r.m.s. value” is displayed. All functions are operative.

z DC
Select this mode when input voltage and current are direct current. The input voltage andcurrent are simply averaged and displayed. Only the voltage, current, and electric powerof the functions are operative. Apparent power, reactive power, power factor, and phaserelated functions are inoperative (− − − − − display).
1φ2W

 Setting wiring type

WIRING

1φ3W

,

3φ3W

,

3φ4W

,

To measure electric power by using the calculating function, press either one of WIRING keys
1φ2W, 1φ3W, 3φ3W, 3φ4W on the front panel according to the actual wiring type.
If the ELEMENT is set to _∑_, the calculation is executed by arithmetic expression of the set
wiring type and the result is displayed.
For the cable connection method and arithmetic expression of the 3-phase power measurement,
see “Connection for power measurement” (p.3-12).
HOLD

 Hold function
HOLD-MD

To hold the measured value, press the HOLD key.
If the HOLD key is pressed, the lamp on the HOLD key lights up, indicating the hold state.
If the HOLD key is pressed again, the lamp on the HOLD key goes off and the measurement
starts.

z Operation in hold state
In the hold state, the reading of voltage and current inputs is stopped. However, thecalculating operation is executed, and accordingly if the FUNCTION or ELEMENT isswitched in the hold state, the waveform data read before the hold are calculated and theresult is displayed.

2721/2722

3 - 17

BASIC OPERATIONS

AVRG

 Measurement average function
AVG-MD

To use the average function, press the AVRG key.
If the AVRG key is pressed, the lamp on the AVRG key lights up and the average function
turns on.
If the AVRG key is pressed again, the lamp on the AVRG key goes off and the average function
turns off.
For the average setting, see “6.4 Average Setting Mode (AVG-MG)” (p.6-5).

Note
The average function of this product has “the moving average and thewavenumber average” which can be set separately.
For the moving average count, increase the count setting if the display is unstable
at low frequencies. However, larger setting retards the response when the input
level changes abruptly.
For the wavenumber average count, increase the count setting if the display isunstable at rapid cycles. However, larger setting retards the display updating cycle,
and dampens the acceptance of operation keys.
AUTO

 Auto range setting
RNG-SETTo switch the voltage and current measurement ranges, the auto range setting for switching
the range automatically and the manual range setting for switching the range manually areavailable.

z Auto range setting
During the auto range setting, the lamp on the AUTO key is lighting. If the lamp on the
AUTO key is in off state, press the AUTO key so that its lamp lights up.
Usually, use the auto range setting. In the auto range setting, the range that meets the
input signal level is selected.

z Manual range setting
If the auto range setting is not used, press the AUTO key to turn off the lamp on the AUTO
key. Use the manual range setting when pulse-shaped waveforms are input and the range
cannot be kept constant.
To check the range in auto range setting mode or to change the range in manual range setting
mode, see “6.5 Range Display and Setting (RNG-SET)” (p.6-6).
SCAL Scaling function
SCL-SETTo use the scaling function, press the SCAL key to turn on the lamp on the SCAL key.
If the scaling function is not used, press the SCAL key again to turn off its lamp.
During use of the scaling function, the measured value multiplied by the scaling value isdisplayed.
For setting the scaling value, see “6.6 Scaling Setting (SCL-SET)” (p.6-7).

3 - 182721/2722

BASIC OPERATIONS

3.4 Setting Displays A, B, C, D, E, F
 Selecting display item and input element
This product has six Displays A, B, C, D, E, and F. Set the items and input elements to be
displayed on respective Displays. For this purpose, select the items to be displayed by using
the FUNCTION keys and ELEMENT keys provided on respective Displays.
FUNCTION moves to the rightone by one

FUNCTION moves to the left
one by one
NF ELECTRONICINSTRUMENTS

NF

2721

PEAK
OVER

POWER MULTIMETERFUNCTION

V1

V

A

W

VA

Var

PF

FUNCTION

deg

V

A

W

VA

Var

PF

SYNC

FUNCTION

deg

V

A

W

VA

Var

PF

POWER

V1

deg

V2

V2

V3

V3
V0
A1

A

A2

Δ

ELEMENT
1

2

3

W

VA

Var

1

2

3

0

B

Σ

Δ

ELEMENT
1

2

3

CNTR

V/A

V/3A

1

2

3

0

C

Σ

1

2

3

Hz

Wh

Ah

1

2

3

0

V0

Δ

ELEMENT

A1
A2

Σ

A3

A3

FUNCTION

A0
V

GPIB
SRQ

A

PF

FUNCTION

deg

V

A

Vsin

FUNCTION

A-B

V

A

Varh

A0

C-D

LIN
E

RMT
ERROR

NO
TRIG

RNG

2

3

0

MODE
AC

STORE/RECALL
1Δ

ELEMENTD

Δ

ELEMENTE

Σ0

COUNTERWIRING
1Φ2W
1Φ3W

4

RESET

CONT

CNTMD

VOLT

CHAT

CONT

CAT-SET

VOLT

START

Δ

ELEMENT

F

Σ

0

Σ

INTEGRATE
B-M

START

STOP

RESET

TIME

HARM

INT-MD

CLOCK

HRM-MD

RS-232CSHIFT

INTERVAL

DC

3Φ3W

3Φ4W

M-B

TRIP

B-M

HOLD

AVRG

AUTO

SCAL

D/A

PRINT

M-B

HLD-MD

AVG-MD

RNG-MD

SCL-SET

DA-SET

PRT-MDONE SHOT

Contents of setting on Displays
A, B, C, D, E, F can be switched

ENTER

ELEMENT moves to the rightone by one (next to Σ is 1)

1 , 2 , 3 , 4

GPIB

Press this key when measuring line
voltage or phase between lines

 Operating STORE/RECALL (display switching) keys
By pressing the STORE/RECALL

LOCAL

●

1

2

3

4

keys, the contents of FUNCTION and

ELEMENT settings on the Displays A, B, C, D, E, and F can be switched.
The settings of measurement mode, wiring type, counter, etc. cannot be switched.
The contents of STORE/RECALL of the number being displayed (its lamp ON), i.e. the contentsof the memory of that number are updated each time the FUNCTION key or ELEMENT key ispressed.
Accordingly, the contents of settings immediately before the power is turned off or the
STORE/RECALL key is pressed are always stored in the memory, not requiring the STORE
operation.
Though six displays are provided, the contents of display can be changed easily by pressing the
STORE/RECALL

1 , 2 , 3 , 4

keys, and therefore 24 displays can be set. Even in thedisplay hold state, if the STORE/RECALL key is switched, the calculation is executed based on
the waveform data, and thus multiple items can be measured synchronously.

2721/2722

3 - 19BASIC OPERATIONS

 Operating FUNCTION keys
If a FUNCTION key is pressed, the display item is switched. Though the item is different
depending on the Display, The key operation and display changing way are same.

Displays A,B,C,D

Shift with▼
key

Shift with▲key

FUNCTION

Contents of display

V

Phase voltage

A

Phase current

W

Active power

VA

Apparent power

Var

Reactive power

PF

Power factor

V

,

A

, deg

Phase difference between voltage and current of phase(reference on voltage)

Display E

Shift with▼
key

Shift with▲
key

Display F

Shift with▼key

3 - 20Shift with
▲
key

V

, deg

Voltage phase difference (reference on SYNC signal)

A

, deg

Current phase difference (reference on SYNC signal)

V

, deg

Voltage phase between lines (between 1-2, 2-3, 3-1) ● lamp ON

A

, deg

Current phase between lines (between 1-2, 2-3, 3-1)

FUNCTION●

lamp ON

Contents of display

V

VoltageA

Current

CNTR

Counter data

V/A

Impedance ( V / A )V/3A

Impedance ( V / ( 3 × A) )Vsin

Impedance ( V / (2 × A × sinφ ) )A-B

Phase difference between Displays A and B (reference on Display A)

FUNCTION

Contents of display

V

VoltageA

Current

Hz

Frequency of SYNC signal

Wh

Integration active powerAhIntegration current

Varh

Integration reactive power

C-D

Phase difference between Displays C and D (reference on Display C)

2721/2722

BASIC OPERATIONS

 Operating ELEMENT keys in phase measurement
If an ELEMENT key is pressed, the input to be measured is selected.
0
is not selected when optional “2725 Input Unit (for ELEMENT 0)” is not installed.

Displays A,B,C,D,E,F ELEMENT
1

Measured value of ELEMENT 1

2

Measured value of ELEMENT 2

3

Measured value of ELEMENT 30

Measured value of ELEMENT 0

Shift with

ELEMENT
key

Contents of display(selectable only when 2725 is installed)
Calculation result of arithmetic expression selected by∑

the wiring type

 Operating ELEMENT keys in line measurement
When the FUNCTION is set to
●

or

V

deg , the line measurement mode is activated if the

key is pressed.

If the●key is pressed, its lamp lights up and two of ELEMENT

up. For example, if

2lights up with

1

1

,

2

,

3

light

lit at the same time, the line between phase 1

and phase 2 is selected.
If the key is pressed again with the lamp lit, the lamp goes off and the ELEMENT display
changes to one.

Displays A,B,C,D,E,F
Shift with

ELEMENT
key

2721/2722

ELEMENT

Contents of display

1

,

2

, ●

Measured values of V12 line voltage and phase

2

,

3

, ●

Measured values of V23 line voltage and phase

3

,

1

, ●

Measured values of V31 line voltage and phase3 - 21BASIC OPERATIONS

3.5 Measuring Voltage, Current, Power, Power
Factor, and Phase Difference Setting FUNCTION and ELEMENT
Set the item and input to be measured by pressing the FUNCTION key and ELEMENT key on
the Displays A, B, C, D, E, and F. Set the WIRING if the ELEMENT is set to ∑ .
However, the electric power and power factor cannot be measured with the Displays E and F.
Also, the phase measurement is partially different.

 Setting measurement conditions
Set the measurement conditions by referring to “3.3 Setting Measurement Conditions”.
To measure AC signals, be sure to press the AC key of the measurement mode setting keys toturn on the AC key lamp.

 Measuring voltage and currentz Measuring phase voltage and phase current
To measure the phase voltage, turn off the

key lamp of the ELEMENT.

●z Measuring line voltage
In the 3-phase 3-wire or 3-phase 4-wire type wiring, the line voltage can be calculated fromthe phase voltage and the interphase phase.
Set the FUNCTION todisplays

1,

2

V , and then press,3●

key of the ELEMENT. Two of ELEMENT

light up, indicating the lines to be measured.

If V1=63.500V, V2=63.500, V1-V2=120.00deg, the line voltage between V1 and V2,
V12=109.99V is displayed.

 Measuring electric powerz Measuring active power
In the active power measurement, if a phase difference between voltage and current is 90
deg to 270 deg (90 to 180 deg, -90 to -180 deg), a minus value is displayed. If a phasedifference between voltage and current is within ±90 deg and active power is displayed as aminus value, exchange the connection of voltage or current.

z Measuring reactive power
In the reactive power measurement, the polarity display is same as phase difference display,
and therefore a plus sign is displayed if the current lags behind the voltage, or a minus signis displayed if the current leads the voltage.

Note
For the plus and minus signs on the Display, “−” is displayed only for a minus value.

3 - 222721/2722

BASIC OPERATIONS Measuring power factor
In the power factor measurement, if active power is a minus value, the power factor is also
displayed with a minus sign. Also, for a phase difference between voltage and current, if thecurrent lags behind voltage, LEAD is shown on the unit display, or if the current leads fromvoltage, LAG

is shown.

 Measuring phase difference
For the phase display, the lag from the reference is displayed with a plus sign.
The factory setting is 0 to 359.99 deg. If the phase display is set to ±180.00 deg, a phasedifference is displayed with plus and minus signs.

z Measuring phase difference between voltage and current of same element
Press the FUNCTION keys to turn on

V , A , degof FUNCTION. Set the element tobe measured with the ELEMENT keys.
A phase difference of current on the basis of voltage is displayed.
This measurement can be made with the Displays A, B, C, and D.

z Measuring phase difference from SYNC signal
Select the reference SYNC signal with the SYNC signal setting key.
Press the FUNCTION keys to turn on

V , degorA , degof FUNCTION. Selectthe element to be measured with the ELEMENT keys.
A phase difference from the SYNC signal is displayed. This measurement can be made with
the Displays A, B, C, and D. However, the measurement is disabled if the SYNC is set toLINE.

z Measuring interphase phase difference of voltage or current
Press the FUNCTION keys to turn on●

V , degorA , deg

key of ELEMENT keys to turn on its lamp. Two of ELEMENT

of FUNCTION. Press
1 , 2 , 3

light up.

Also, same display can be obtained by pressing the FUNCTION key continuously. For theoperation of FUNCTION keys, see “3.3.4 Setting Displays A, B, C, D, E, F”.
A phase difference between phases of voltage or current indicated on ELEMENT isdisplayed. This measurement can be made with the Displays A, B, C, and D.

z Measuring phase difference of voltage or current between Displays
A phase difference of voltage or current between Displays A and B, or Displays C and D canbe measured. A phase difference between Displays A and B can be shown on Display E, orthat between Displays C and D can be shown on Display F.
Set the FUNCTION on Display E to A-B , and display the voltage or current to be measured
on the Displays A and B, so that a phase difference of Display B from the Display A isshown on the Display E with “a plus sign for lag or minus sign for lead”. Similar display canbe made on the Display F.

2721/2722

3 - 23

BASIC OPERATIONS

3.6 Other Measurements
 Impedance measurement
Press the FUNCTION key on the Display E to select either V / A , V/3A , Vsin and press the
ELEMENT key to set the input to be measured.
The result calculated with an arithmetic expression that corresponds to the selected
FUNCTION is shown on the Display E.
Arithmetic expressions are as follows:

Display E

FUNCTION

Arithmetic expression

V/A

V/A

V/3A

V / ( 3 × A)

Vsin

V / (2 × A × sinφ )The unit is “ohm” for all items.

 Frequency measurement
Press the FUNCTION key on the Display F to selectHz . Set the input to be measured with

the SYNC signal setting key.
The unit is “Hz”.

3 - 242721/2722

4. COUNTER FUNCTION

This chapter describes how to operate the counter function of the “2721/2722 PowerMultimeter”.
For the description of counter function operating keys, see “ Names and operations ofcomponents on front panel and side/rear panel (side panel for 2721, or rear panel for 2722)”
in “3. BASIC OPERATIONS”.
The counter operation, signal type, and signal logic can be set on the front panel. Also, thesignal input state is displayed on the front panel.
For the counter operation, the Interval mode (time difference measurement) and One Shotdate 2010/1/13(#7)

mode (pulse width measurement) are available.

2721/2722

4-1

COUNTER FUNCTION

4. 1 COUNTER FUNCTION
 Description of counter operation
This section describes the operation modes of the counter.
INTERVAL

key. See “4.4.3 Setting counter

The counter operation modes can be switched with the
ONESHOT

Measurement Conditions” (p.4-5).
SHIFT

For the mode setting of respective operations, press

RESET

+

keys to activate the counter
CNTMD

setting mode. For further information, see “4.4.4 Counter Setting Mode” (p.4-8).

z INTERVAL mode (time difference measurement)This mode is for measuring a time difference from the start signal to the trip signal.
The Interval mode provides the following three modes:(1) Single : Either operation time or recovery time is measured.
(2) Dual: The operation time (counter 1) and recovery time (counter 2) are measured at
the same time.

(3) Multi : The operation time and recovery time are measured at the same time, andrespective maximum values and minimum values are stored.
In the single interval mode, the operation time or recovery time is shown on the Display E.
In the dual interval mode, the operation time is shown on the Display E, and the recovery
time is shown on the Display F. In the dual interval mode, the Displays E and F are used,
and therefore the FUNCTION on Display F does not light up.
In the multi interval mode, the operation time is shown on the Display B, maximum valueof operation time on Display A, minimum value on Display C, recovery time on Display E,
maximum value of recovery time on Display D, and minimum value on Display F
respectively. The multi interval mode uses all Displays and therefore the FUNCTION on
Displays A, B, C, D, E, F do not light up. CNTR of FUNCTION on the Display C lights up.
(1) Single
START input(Abrupt change
Normalsignal)TroubleTRIP input(Response
signal)Operationtime(2) Dual
START input(Abrupt change Normal
signal)TroubleTRIP input(Response
signal)4-2Counter 1

Operation
time

Counter 2

Recovery time

2721/2722

COUNTER FUNCTIONz ONE SHOT mode (pulse width measurement)This mode is for measuring the trip signal width.
The One Shot mode provides the following two modes:(1) One Shot : The operation time (1) shown in the following figure is measured, and thenthe operation time (2) is measured by the next trip input.
(2) Train: The operation time (1) is measured, and the operation time (2) is measured
by the next trip input and added to (1).

In the one shot mode, the measurement result (operation time) is shown on the Display E.
(1) One Shot

TRIP input
Measurement time

Measurement time
RESET(2) Train

TRIP input
Operation time (T1)

Operation time (T2)

Measurement time = (T1+T2)

2721/2722

4-3

COUNTER FUNCTION

4.2 Counter Input Terminals
The START, TRIP and RESET terminals have the circuits as shown below.
The START and TRIP inputs are isolated from the case. However, the RESET input has thecase potential, requiring attention.
The “contact input” and “voltage input” of START and TRIP inputs are switched by the relays.
Also, the “threshold value” of TRIP input is switched by the resistors.
+12
1kΩ

39kΩ

160kΩ

START
COMP

100kΩ

P

±2V

±

C1

Figure 4-1

START Input Circuit+12

Threshold
value

1kΩ

R2

±2.5V
±8V
±50V

100kΩ

COMP

R1

TRIP
P

R1

R2

39kΩ 160kΩ
150kΩ 51kΩ
200kΩ 2.8kΩ

±2V

±

C2

Figure 4-2

+5V

1kΩ

RESET

100kΩ

+
-

+5V
74HC04D

Figure 4-3

4-4

TRIP Input Circuit

Reset Input Circuit

2721/2722

COUNTER FUNCTION

4.3 Setting Counter Measurement Conditions
This section describes how to set the measurement conditions of the counter.
INTERVAL/ONE SHOTSTART/TRIP
Input monitor

Time measurement mode setting
NF ELECTRONICINSTRUMENTS

NF

2721

PEAK
OVER

POWER MULTIMETERFUNCTION

V1

V

A

W

VA

Var

PF

FUNCTION

deg

V

A

W

VA

Var

PF

SYNC

FUNCTION

deg

V

A

W

VA

Var

PF

POWER

V1

deg

V2

V2

V3

V3
V0
A1

ELEMENT

A

A2

1

2

3

W

VA

Var

1

2

3

0

Δ

Δ

ELEMENT

B

Σ

1

2

3

CNTR

V/A

V/3A

1

2

3

0

1

2

3

Hz

Wh

Ah

1

2

3

0

V0

Δ

ELEMENT

C

Σ

A1
A2

Σ

A3

A3

FUNCTION

A0
V

GPIB
SRQ

A

PF

FUNCTION

deg

V

A

Vsin

FUNCTION

A-B

V

A

Varh

A0

C-D

LIN
E

RMT
ERROR

NO
TRIG

RNG

ELEMENT

D

MODE
AC

STORE/RECALL
1

2

3

0

Δ

0

RESET

CONT

START

Δ

ELEMENTFΣCOUNTERWIRING
1Φ2W
1Φ3W

4

Δ

ELEMENT

E

Σ

0

Σ

INTEGRATE
START

STOP

B-M

HOLD

AVRG

M-B

HLD-MD

AVG-MD

B-M

RESET

RS-232C

TIME

HARM

INT-MD

CLOCK

HRM-MD

AUTO

SCAL

D/A

PRINT

RNG-MD

SCL-SET

DA-SET

PRT-MDSHIFTINTERVAL

DC

3Φ3W

3Φ4W

CNTMD

VOLT

CHAT

CONT

CAT-SET

VOLT

M-B

TRIP

ONE SHOTRESETCounter reset key
CHAT
Chattering eliminating function key

ENTER

LOCAL

●
GPIB

B-M/M-B
Input operation mode setting keys

CONT/VOLT
Input format setting keys

INTERVAL Setting time measurement mode (INTERVAL/ONE SHOT)ONESHOTTo measure a time difference from the start input to the trip input, press the INTERVAL/ONE
SHOT key to turn on its lamp, so that the Interval mode is activated for the counter operation.
To measure the pulse width time of the trip input, press the INTERVAL/ONE SHOT key to turnoff its lamp, so that the One Shot mode is activated for the counter operation.
Even in the Interval mode, if the operation time and recovery time of the output of relays, etc.
are to be measured individually, set the single interval mode, or if they are to be measured
simultaneously, set the dual interval mode. Also, if the maximum value and minimum value ofthe operation and recovery time are to be obtained in the dual interval mode, set the multiinterval mode.
In the One Shot mode, if the pulse width time is to be integrated, set the one shot train mode.

2721/2722

4-5

COUNTER FUNCTION

RESET Resetting the counter (RESET)CNTMDThis key resets the counter display to 0.0000s.
Since the counter is automatically reset, the RESET key does not need to be pressed in the
single interval mode, dual interval mode, and one shot mode. However, to reset the maximum
value and minimum value in the multi interval mode, or to reset the integrated time in the
train mode, press the RESET key.
CONT

 Setting START or TRIP input type (CONT/VOLT)VOLT

For the START or TRIP input format, the “contact input (CONTact)” and “voltage input(VOLTage)” are available.
When the input signal is a contact signal, turn on the CONT/VOLT key lamp. If it is a voltage
signal, turn off the CONT/VOLT key lamp.

！ CAUTION
Do not apply voltage from outside with the START or TRIP input set to thecontact (CONT). Internal circuits may be damaged.
Be sure to set the input type before connecting a signal.

Note
Set CONT or VOLT individually for the START and TRIP inputs. The upper
CONT/VOLT key is for START input, and the lower key is for TRIP input.

B-M

 Operation modes of START and TRIP inputs (B-M/M-B)
M-B

For the operation modes of START and TRIP inputs, “Break (open) → Make (short)” and“Make (short) → Break (open)” are available.
Turn on the B-M/M-B key lamp if an input signal operates when the contact closed (shorted), or
if it operates when a voltage signal moved from larger voltage than threshold value to smaller
voltage. Or, in reverse case, turn off the key lamp.

Note
Set B-M or M-B individually for the START and TRIP inputs. The upper B-M/M-B
key is for START input, and the lower key is for TRIP input.

4-6

2721/2722

COUNTER FUNCTION

 Monitoring START and TRIP inputs

START

,

TRIP

The START and TRIP input states can be monitored with the lamps on the front panel.
The lamp lights up when a signal with which the counter operates is input. For example, if the
START input is set to CONT (lamp ON) and B-M (lamp ON), the lamp goes off when the
START input opened, or the lamp lights up when shorted.
Table 4-1

START and TRIP Input Monitor Lamp Indication

CONT/VOLT

B-M/M-B

Input

Monitor lamp

CONT

B-M

Open

OFF

(Lamp ON)

(Lamp ON)

Short

ON

M-B

Open

OFF

(Lamp OFF)

Short

ON

VOLT

B-M

±10V

OFF

(Lamp OFF)

(Lamp ON)

0V

ON

Threshold value

M-B

±10V

OFF

=±2.5V(Lamp OFF)

0V

ON

Note
In the Interval mode, the counter does not start even if the START signal is input
unless the TRIP input monitor lamp is in OFF state.
Be sure to confirm that the START and TRIP monitor lamps are in OFF state.

CHAT Chattering eliminating function (CHAT)
CAT-SETTo use the chattering eliminating function, press the CHAT key.
If the CHAT key is pressed, the CHAT key lamp lights up and the chattering eliminating
function operates.
If the CHAT key is pressed again, the CHAT key lamp goes off and the chattering eliminating
function stops.
The chattering eliminating function removes the chattering of the TRIP signal.
For setting the chattering eliminating time, see “4.4 Counter Setting Mode” (p.4-8).

2721/2722

4-7

COUNTER FUNCTION

4.4 Counter Setting Mode
This section describes the “counter operation setting mode” and “chattering time setting”.

 Counter setting mode (CNTMD)
SHIFT

Press the

RESET

+

keys to activate the counter setting mode.
CNTMD

The counter setting mode enables the setting of Interval mode and One Shot mode, on/off ofexternal counter reset function, and switching of voltage threshold value of trip input.

z Display of counter setting mode
Trip threshold value ±50V

Trip threshold value ±8V

Counter setting mode

Trip threshold value ±2.5V

MODE
A

Interval mode

D

Single+/-V
B

One Shot modeE

One Shot

INTV

Dual

C

External reset function

F

Off

ONES

Train

REST

On

Multi

• Display A : “CoUnt MODE”

Indicates the counter setting mode

• Display C : “trP2.5+/-V”

Trip input threshold value (±2.5V/±8V/±50V)• Display D : “SinGL INTV”

Interval mode setting(Single/Dual/Multi)• Display E : “onESt”

One Shot mode setting(One Shot /Train)• Display F : “oFF”

External reset function setting (ON/OFF)z Counter setting• Cursor initial positionÎ• Setting item selectionÎ

Display D (Interval setting mode)
▲ ,
RESET

• Setting canceling method Î

or
CNTMD

4-8

▼

keys

SHIFT

RESET

+
CNTMD

2721/2722

COUNTER FUNCTION

 Chattering time setting (CAT-SET)
CHAT

SHIFT

Press the+keys to activate the chattering time setting mode.
CAT-SET

Set the chattering time.

z Display of chattering time setting mode
SET
A

B

C
ms

D

E

F

Cursor initial position• Display A : “CHAt- SET”

Indicates the chattering time setting mode

• Display F : “100.0ms”

Chattering time setting 1-125 ms (setting resolution 1ms)

z Chattering time setting• Cursor initial position

Î Digit of 1ms (cursor does not move to the digit of 0.1ms)• Setting item selection

Î

▲ ,

▼

CHAT

• Setting canceling method Î

orCAT-SET

2721/2722

keys
CHAT

SHIFT

+
CAT-SET

4-9

COUNTER FUNCTION

4.5 Time Measurement
 Time measurement method
Set the FUNCTION on the Display E to CNTR .
Set the measurement conditions with the INTERVAL/ONE SHOT key, CONT/VOLT key, and BM/M-B keys in the COUNTER operation block.

Note
The counter display is executed independently from the display and update ofvoltage and current.
However, the counter display is not updated during the reading of waveform data.
Accordingly, if the large wavenumber average count of average settings is set, thecounter will not be displayed smoothly, but this is not a trouble.
When the counter is to be displayed smoothly, turn off the average function.

 Displaying counter data
In the Interval mode, the counter display varies depending on which mode, single, dual, or
multi, is selected.
With the Display E set to CNTR when the INTERVAL/ONE SHOT key lamp is turned on to
set the Interval mode, if only the Display E shows the time, the single interval mode isactivated, or if the Displays E and F show the time, the dual interval mode is activated, or if all
Displays show the time, the multi interval mode is activated.
In the One Shot mode, only the Display E shows the time.

z Display in single interval mode, one shot mode, and train mode

V
A

mA
B

VA
D

W
C

ms
E

Hz
F

The operation time is shown on the Display E. In the above case, the counter value is“200.5ms”.

4 - 102721/2722

COUNTER FUNCTIONz Displaying dual interval mode

V
A

mA
B

VA
D

W
C

ms1
E

ms2
F

The Display E shows the counter 1 (operation time) and the Display F shows the counter 2(recovery time).

z Displaying multi interval mode

ms1Ï
A

ms1
B

C

ms2Ï
D

ms1Ð

ms2
E

ms2Ð
F

The Display B shows the measured value [ms1 ] of counter 1 (operation time), the Display A
shows the maximum value [ms1Ï] of counter 1, and the Display C shows the minimum
value [ms1Ð] of counter 1.
The Display E shows the measured value [ms2 ] of counter 2 (operation time), the Display Dshows the maximum value [ms2Ï] of counter 2, and the Display F shows the minimum
value [ms2Ð] of counter 2

 Time measurement range
The time measurable range and the time measurement range are as follows:• Time measurable range: 0.1ms to 1677s• Time measurement range (display resolution)
0.1ms

to 999.9ms(0.1ms)

1.0000s to 9.9999s(0.0001s)
10.000s to 99.999s(0.001s)
100.00s to 999.99s(0.01s)
1000.0s to 1677.0s(0.1s)
The time is displayed as “0.0000s” when reset.

2721/2722

4 - 11COUNTER FUNCTION

MEMO

4 - 122721/2722

5. INTEGRATING FUNCTION

This chapter describes how to operate the integrating function of the “2721/2722 PowerMultimeter”.
For the description of integrating function operating keys, see “ Names and operations ofcomponents on front panel and side/rear panel (side panel for 2721, or rear panel for 2722)”
in “3. BASIC OPERATIONS”.

2721/2722

5-1

INTEGRATING FUNCTION

5.1 Measuring Integrated Active Power, Current, andReactive Power Integrate mode
For the integration measurement, set the FUNCTION on Display F to either W h , Ah ,,orVarh .
The integration result is shown on the Display F. Respective integrated values can bedisplayed. Also, the input element can be changed.
However, during the integrating operation, the following limitations are applied. To cancel thelimitations, press the STOP key to stop the integration and press the RESET key to reset the
integrated value.
z The average function is turned off.
z The FUNCTION on Display F cannot be set, except W h , Ah , and Varh .
z During the integrating operation, do not switch the display with the STORE/RECALL key.
Normal integrating operation may not be performed.

Note
When the Display E is set to CNTR and the Display F is used for counter display, thecounter display has priority and therefore the integration measurement cannot be used.
The Integrate mode has the following three modes:
Integrate mode

Operation of INTEGRATE keys / Integrating operation
START

Manual integrate mode

Press START

STOP

key to start integration, STOP

key to stop

RESET

key to rest the integrated value.

integration, and RESET
INT-MD
START

Time integrate mode

key to start integration, and after the time set

Press START

to the timer elapsed, the integration stops.
RESET

key to rest the integrated value. Restart is

Press RESET
INT-MDpossible.
START

Real time integrate mode

After START

key is pressed, the integration starts at thereserved start time and stops at the stop time.

Note
Even after pressing the START key to start the real time integration, do not set the
FUNCTION on Display F to any item other than W h , Ah , and Varh until the starttime.
Normal integrating operation may not be performed, if the function is set to any item
other than W h , Ah , Varh when the integration starts at the start time.

5-2

2721/2722

INTEGRATING FUNCTION

 Integration display update cycle
The display update cycle of the integrated value is about one second.
During the integrating operation, the average function is automatically turned off.

 Display of integrated time
During the integrating operation, the integrated time can be monitored.
TIME

key is pressed during the integrating operation, the integrated time is shown on the

If the
CLOCK

Display F.
V
A

mA
B

deg
D

mW
C

deg
E

37s
F

The Display F shows the integrated time, and it is “7 hours 14 minutes 37 seconds” in theabove case. The integrated time display returns to the integrated value display in about 10
seconds.

2721/2722

5-3

INTEGRATING FUNCTION

5.2 Integration setting mode (INT-MD)
RESET

SHIFT

Press thekeys to activate the integrate setting mode.

+
INT-MDIn the integration setting mode, the integrate mode, integrated time, integration start time,and integration stop time can be set.

 Display of integration setting mode
MODE
A Integrate mode

B

C

D Manual integrate mode

E

F

Time integrate mode

Real time integrate mode

• Display A : “intGr”

Indicates the integration setting mode

• Display D : “norML”

Manual integrate mode“tiMEr”

Time integrate mode

“rtiME”

Real time integrate mode
RESET

• Setting canceling method

SHIFT

or

Î
INT-MDRESET+
INT-MD Display of manual integrate mode
MODE
A

B

C

D Manual integrate mode

E

F

• Display D : “norML”

Manual integrate mode
In the manual integrate mode, only the Display D is used for display, and Displays B, C, E,
and F do not display anything at all.

5-4

2721/2722

INTEGRATING FUNCTION

 Displaying and setting time integrate mode
MODE
A

B

C
H.M

D Time integrate mode

E

• Display D : “tiMEr”• Display E : ”000.10 H.M”

F

Integrated time: 10 minutes

Time integrate mode
Displays the setting of integrated time (in this case,integrated time setting is 10 min.)Higher-order digits than decimal point show hours, anddecimal places show minutes.

• Setting methodÎ▲ ,▼ keysHour is shown in ± 100th digit, 10th digit, unit digit, andminute is shown in ± every minute.
• Cursor moving method Î Cursor moving method → Cursor moves to “Display D ⇔100th digit ⇔ 10th digit ⇔ unit digit ⇔ minute digits ⇔Display D”.
Minute digits blink together (resolution is 1 minute).

 Displaying and setting real time integrate mode

MODE
A

STRT
B

1996
C

Start time

Start date

STOP
D Real time integrate mode

E

• Display D : “rtiME”• Display B : “08-00 STRT”

1997
F

Stop time

Stop date

Real time integrate mod
Integration start time set value “8:00”• Display C : “01-10 1996”• Display E : “08-00 STOP”

Integration start time set value “8:00”• Display C : “07-01 1997”

Integration start date set value “July 1, 1997”• Setting method▲ ,ÎIntegration start date set value “January 10, 1996”

▼

keys

Time is shown in ± every hour and every minute, and month in± every month, day in ± every day, year in ± every year.

• Cursor moving method Î Display D”⇔ Hour of start time ⇔ Minute of start time
⇔ Month of start date ⇔ Day of start date ⇔ Year of start date
⇔ Hour of stop time ⇔ Minute of stop time
⇔ Month of stop date ⇔Day of stop date ⇔Year of stop date
⇔ Cursor moves to “Display D

2721/2722

5-5

INTEGRATING FUNCTION

MEMO

5-6

2721/2722

6. SETTING OPERATION WITH SHIFT KEY

This chapter describes a setting operation that uses the

SHIFT

key of the “2721/2722 PowerMultimeter”.
For a measuring method, see “3. Basic Operations”.
Also, as alphanumeric characters shown on digital displays A, B, C, D, E, F (7 segments)
include some characters which may be difficult to read, refer to “Description of displayed

date 2010/1/13(#326)

characters” (p.3-2).

2721/2722

6-1

SETTING OPERATION WITH SHIFT KEY

6.1 Setting Modes with SHIFT Key
When the SHIFT key is pressed and its lamp is lighting, the modes indicated with blue
characters on the lower side of respective setting keys are active.
The settings using the SHIFT key are as follows:

SHIFT+

Description
HOLD

HOLD-MD

Sets the hold mode
HOLD-MD

AVRG

AVG-MD

Set the phase display range (0 to 360deg/±180deg)
Turns on/off the hold function by trip input
Sets the average count

AVG-MD

AUTO

RNG-SET

Set the moving average count (1, 2, 4, 8, 16, 32, 64)
Set the wavenumber average count (1, 2, 4, 8, 16, 32)
Range display / setting

RNG-SETSCAL

SCL-SETAt auto range setting ON: Displays the range
At auto range setting OFF: Sets the manual range
Sets the scaling

SCL-SET

TIME

CLOCK

Set the scaling mode (all setting, individual setting)Set the scaling value
Sets the date and time

CLOCK

The following setting modes are described in other chapters. See the given pages.
RESET

CNTMD

Sets the counter
CNTMD

Set the Interval mode (single, dual, multi)
Set the One Shot mode (one shot, train)
Turns on/off external reset function
Set the voltage threshold value of trip input (±2.5V, ±8V, ±50V)

CHAT

CAT-SET(See p.4-8)
Sets the chattering time (1ms to 125ms)

CAT-SETRESET

INT-MD(See p.4-9)
Sets the integration

INT-MD

Set the Integrate mode (manual, time, and real time integrate modes)
Set the integrated time, start time and stop time
(See p.5-4)

6-2

2721/2722

SETTING OPERATION WITH SHIFT KEY

6.2 Setting Mode Common Operations
This section describes the common operations in the setting modes such as “cursor movements,
item selection, setting, and cancel of setting”.
To activate the setting mode, press the SHIFT key to turn on its lamp and press the key
indicated with blue characters.
Even in the setting mode, the measurement continues, and therefore if large wavenumber
average count is set with the average function, the operation of a key will not be accepted
immediately. In such a case, turn off the average function.
In the setting mode, the name of setting mode (characters similar to blue characters of thekey) is shown on the Display A. The contents of setting are shown on other Displays. When
there is one setting item, it is shown on Display F, or they are shown on Displays E and F
when two, or Displays D, E and F when three, or on Displays D, E, F and C when four.
However, the real time setting in the Integrate mode uses all Displays.
The cursor is located in the digit or Display that is blinking. The initial cursor position varies▲,▲

depending on the setting mode. To move the cursor, use

keys.

To select each item of setting mode or to change a numeric value, use ▲ , ▼ keys.
To set each item and numeric value in the setting mode, press the ENTER key at the end. The
set values of respective items are written in the memory (nonvolatile).
To cancel the setting mode, press each setting mode key before pressing the ENTER key. Even
if an item was changed on the front panel, the settings are not written in the memory but
cancelled.
INT-MD key
Integration setting(p.5-4)
NF ELECTRONICINSTRUMENTS

NF

2721

PEAK
OVER

CLOCK key
Date and time setting(p.6-8)POWER MULTIMETERFUNCTION

V1

V

A

W

VA

Var

PF

FUNCTION

deg

V

A

W

VA

Var

PF

SYNC

FUNCTION

deg

V

A

W

VA

Var

PF

POWER

V1

deg

V2

V2

Cursor moving keys
Item selection keys

V3

V3
V0
A1

ELEMENT

A

A2

1

2

3

W

VA

Var

1

2

3

0

Δ

B

Σ

Δ

ELEMENT
1

2

3

CNTR

V/A

V/3A

1

2

3

0

C

Σ

1

2

3

Hz

Wh

Ah

1

2

3

0

V0

Δ

ELEMENT

A1
A2

Σ

A3

A3

FUNCTION

A0
V

GPIB
SRQ

A

PF

FUNCTION

deg

V

A

Vsin

FUNCTION

A-B

V

A

Varh

A0

C-D

LIN
E

RMT
ERROR

NO
TRIG

RNG

ELEMENT

D

MODE
AC

STORE/RECALL
1

2

3

0

Δ

0

RESET

CONT

START

Δ

ELEMENTFΣCOUNTERWIRING
1Φ2W
1Φ3W

4

Δ

ELEMENT

E

Σ

0

Σ

INTEGRATE
B-M

START

STOP

RESET

TIME

HARM

INT-MD

CLOCK

HRM-MD

RS-232CSHIFT

INTERVAL

DC

3Φ3W

3Φ4W

CNTMD

VOLT

CHAT

CONT

CAT-SET

VOLT

M-B

TRIP

B-M

HOLD

AVRG

AUTO

SCAL

D/A

PRINT

M-B

HLD-MD

AVG-MD

RNG-MD

SCL-SET

DA-SET

PRT-MDONE SHOT

2721/2722

LOCAL

GPIB

SCL-SET key
Scaling setting(p.6-7)

CNTMD key
Counter setting mode
(p.4-8)

CAT-SET key
Chattering time setting(p.4-9)ENTER●

HOLD-MD key
Hold mode setting(p.6-4)ENTER key
Writing the settings

RNG-SET key
Range display/setting(p.6-6)
AVG-MD key
Average count setting mode
(p.6-4)

6-3

SETTING OPERATION WITH SHIFT KEY

6.3 Hold mold setting (HOLD-MD)
SHIFT

Press theHOLD

keys to activate the hold mode setting.

+
HOLD-MDIn the hold mode setting, the on/off of hold function by the trip input and the phase display
range can be set.

 Display of hold mode setting mode

MODE

disp
B

A

Phase display range setting

TRIP
C

External hold function setting

F

OFF

+LAG
D

E 0.00～360.00deg

ON-180.00～180.00deg• Display A : “HoLd- MODE”

Indicates the hold mode setting mode

• Display B : “deG-dsip”

Indicates that the phase display range is shown on Display E• Display C : “HoLd-TRIP”

Indicates that the hold function setting by trip input isshown on Display F• Display E : “360.00+LAG”

Phase display range set value• Display F : “ oFF”

Setting of hold function by trip input

 Hold mode setting• Cursor initial position

Î Display E, the cursor moves to Displays E and F only

• Setting method

Î

▲ ,

▼

keys

• Phase display range setting Î 0.00 to 360.00deg / −180.00 to 180.00deg• Hold function settingÎ ON/OFFHOLD• Setting canceling method Î

SHIFT

or
HOLD-MD

HOLD+
HOLD-MD

For an input method of trip, see “4. Counter Function”.

6-4

2721/2722

SETTING OPERATION WITH SHIFT KEY

6.4 Average setting mode (AVG-MD)
SHIFT

Press theAVRG

keys to activate the average setting mode.

+
AVG-MDIn the average setting mode, the moving average count and wavenumber average count can beset.

 Display of average setting mode

MODE
B

A

C
LINR

D

E

WAVE
F

Moving average count

Wavenumber average count• Display A : “AvrG- MODE”

Indicates the average setting mode

• Display E :“1”

Set value of moving average count• Display F :“1”Set value of wavenumber average count Average setting• Cursor initial position

Î Display E, the cursor moves to Displays E and F only

• Setting methodÎ• Moving average countÎ Set either 1 / 2 / 4 / 8 / 16 / 32 / 64

▲ ,

▼

keys

• Wavenumber average count Î Set either 1 / 2 / 4 / 8 / 16 / 32
AVRG

• Setting canceling method Î

SHIFT

or
AVG-MD

AVRG+
AVG-MD

Increase the moving average count if the display is unstable at low cycles. However, larger
setting retards the response when the input level changes.
Increase the wavenumber average count if the display is unstable at rapid cycles. However,larger setting retards the display updating cycle, and dampens the acceptance of operation
keys.

2721/2722

6-5

SETTING OPERATION WITH SHIFT KEY

6.5 Range display/setting (RNG-SET)
SHIFT

Press theAUTO

keys to activate the range display/setting mode.

+
RNG-SET

AUTO

When

AUTO

key lamp lights up, the range display mode is activated. When

key lamp

RNG-SETRNG-SET

goes off, the range setting mode is activated.
FUNCTION keys

FUNCTION keys

Voltage range switching

Current range switching

V
A

mA
B

mW
C

FUNCTIONFUNCTION

V

A

mVA
D

Vrng
E

F

ELEMENT

1

2

3

0

Voltage range value display

Arng
ELEMENT

1

2

3

0

Current range value display

ELEMENT keys

ELEMENT keys

Voltage range display element switching

Current range display element switching Range display mode
• Display E : “r1.0”

Displays the voltage range• Display F : “r 0.04”

Displays the current range• Element switchingÎ For voltage range, use ELEMENT keys on Display E
For current range, use ELEMENT keys on Display F
AUTO• Display cancel method Î

SHIFT

or

AUTO

+

RNG-SETRNG-SET Range setting mode
• Display E : “r1.0”

Displays the voltage range• Display F : “r 0.04”

Displays the current range• Range changeÎ For voltage range, use FUNCTION keys on Display E
For current range, use FUNCTION keys on Display F
To reduce the range, press
key

press
• Element switching

key, or to increase the range,

Î For voltage range, use ELEMENT keys on Display E
For current range, use ELEMENT keys on Display F
AUTO• Display cancel method Îor
RNG-SET

6-6

SHIFT

AUTO

+
RNG-SET

2721/2722

SETTING OPERATION WITH SHIFT KEY

6.6 Scaling setting (SCL-SET)
SHIFT

Press theSCAL

keys to activate the scaling setting mode.

+
SCL-SETIn the scaling setting mode, whether the scaling values are set all together or individually canbe selected and also the scaling values can be set.

 Display of scaling setting
SET
A

B
Scaling modeV

D All setting modeC

FUNCTION
Voltage scaling value

E

A

F

ELEMENT

1

2

3

0

FUNCTION
Current scaling value

ELEMENT

1

2

3

0

ELEMENT display

Individual setting mode

All setting: All elements light up
Individual setting: Only the set element lights up
Switching with ELEMENT keys

• Display A : “SCALE SET”

Indicates the scaling setting mode

• Display D : “ALL/ind”

Indicates the scaling mode“ALL” indicates all setting, and “ind” indicates individual
setting.

• Display E : “1.0000”

Voltage scaling value• Display F : “1.0000”

Current scaling value

 Scaling setting• Cursor initial position Î Display D• Setting methodÎ▲ ,▼ , ・ keys

With ・ key, the decimal point of scaling value moves andthe unit changes.
The decimal point and unit change in the following order:km• ELEMENT switchingmkÎ For voltage scaling, use ELEMENT keys on Display E
For current scaling, use ELEMENT keys on Display F
SCAL• Display cancel method Î

SHIFT

or
SCL-SET

2721/2722

m

k

SCAL

+
SCL-SET

6-7

SETTING OPERATION WITH SHIFT KEY

6.7 Date and time setting(CLOCK)
SHIFT

Press theTIME

keys to activate the date and time setting mode.

+
CLOCK

In the date and time (CLOCK) setting mode, the date and time of internal clock can be set.

 Display of date and time setting
NOW>
A

00s
B

1996
C

Internal time

Internal date

SET>

1996

D

E

• Display A : “CLoCk”

F

Set time

Set date

Indicates the date and time setting mode.
Indicates that Displays B and C are internal time and internal

NOW>

date.
Indicates that Displays E and F are internal time and

SET>internal date.
• Display B : “12-00 00s”

Internal time (12H00M00S)• Display C : “07-15 1996”

Internal date (July 15, 1996)• Display D : “12-00 00s”

Set time (12H00M00S)
Initial value is same as internal time on Display C.

• Display E：”07-15 1996”

Set date (July 15, 1996)
Initial value is same as internal date on Display C.

 Date and time setting• Cursor initial valueÎ Year “96” on Display F• Setting method

Î Year month day and hour minute are incremented or
decremented by

▲ ,

▼

keys.

Year changes like “1996↔1997↔1998↔1999↔2000↔2001↔ ....”.
TIME• Setting cancel

SHIFT

or

Î
CLOCK

TIME

+
CLOCK

[Example] To change the day 15 to day 21, press▲
day “15” and press▲

key 6 times.

NOW>A

key to move the cursor (blinking) to

52s
BInternal time

1996
C

Internal date

SET>
D

6-8

1996
E

Set timeF

Set date

2721/2722

7. REMOTE CONTROL FUNCTION

This chapter describes the GPIB interface and RS-232C interface of remote control function of
the “2721/2722 Power Multimeter”.
Using the GPIB interface or RS-232C interface enables the remote control and the datareading.
Though the GPIB interface and RS-232C interface are equipped as standard, they cannot bedate 2010/1/13(#3)

used for communication at the same time.

2721/2722

7-1

REMOTE CONTROL FUNCTION

7.1 Setting GPIB / RS-232C
This section describes the GPIB setting (address and delimiter setting) and RS-232C setting(communication condition setting).

NF ELECTRONICINSTRUMENTS

NF

2721

PEAK
OVER

POWER MULTIMETERFUNCTION

V1

V

A

W

VA

Var

PF

FUNCTION

deg

V

A

W

VA

Var

PF

SYNC

FUNCTION

deg

V

A

W

VA

Var

PF

POWER

V1

deg

V2

V2

V3

V3
V0
A1

A

A2

Δ

ELEMENT
1

2

3

W

VA

Var

1

2

3

0

B

Σ

Δ

ELEMENT
1

2

3

CNTR

V/A

V/3A

1

2

3

C

Σ

0

1

2

3

Hz

Wh

Ah

1

2

3

0

V0

Δ

ELEMENT

A1
A2

Σ

A3

A3

FUNCTION

A0
V

GPIB
SRQ

A

PF

FUNCTION

deg

V

A

Vsin

FUNCTION

A-B

V

A

Varh

RS-232C
Sets the RS-232C

A0

C-D

LIN
E

RMT
ERROR

NO
TRIG

RNG

ELEMENT

D

2

3

Δ

0

RESET

CONT

START

Δ

ELEMENTFΣCOUNTERWIRING
1Φ2W
1Φ3W

4

Δ

ELEMENT

E

Σ

MODE
AC

STORE/RECALL
1

0

0

Σ

INTEGRATE
START

STOP

B-M

HOLD

AVRG

M-B

HLD-MD

AVG-MD

B-M

RESET

RS-232C

TIME

HARM

INT-MD

CLOCK

HRM-MD

AUTO

SCAL

D/A

PRINT

RNG-MD

SCL-SET

DA-SET

PRT-MD

LOCAL

SHIFT

Cancels the remote state

INTERVAL

DC

3Φ3W

3Φ4W

CNTMD

VOLT

CHAT

CONT

CAT-SET

VOLT

M-B

TRIP

ONE SHOT

ENTER

LOCAL

●
GPIB

SHIFT+GPIB
GPIB setting Setting GPIBSHIFT

To activates the GPIB setting mode, press

LOCAL

+

keys.
GPIB

SET
A

B

C
adrs

D

E

dlmt
F

• Display A : “GPib SET”

Indicates the GPIB setting mode

• Display E : “7 adrs”

GPIB address set value (0 to 30)• Display F : “Cr-LF dlmt”

GPIB delimiter set value (“Cr-LF” / “Cr-”)• Cursor initial position

Î Display E, the cursor moves to Displays E and F only

• Setting method

Î

▲ ,
SHIFT

• Setting canceling method Î

▼

keys.

LOCAL

+
GPIB

After selecting respective setting items, press the ENTER key. The set values are written in
the memory (nonvolatile).

7-2

2721/2722

REMOTE CONTROL FUNCTION Setting RS-232C
RS-232C

To activates the RS-232C setting mode, press

keys.

SET

bps

A

B
stop

C
prty

D

dlmt

E

F

• Display A : “rS232- SET”

Indicates RS-232C setting mode

• Display C : “4800 bps”

RS-232C data rate set value(600bps/1200bps/2400bps/4800bps)• Display D : “1bit stop”

RS-232C communication stop bit set value
Select either 1bit (1 stop bit) or 2bit (2 stop bits)• Display E : “non prty”

RS-232C communication parity check set value
Select either “non” (no parity), “EvEn” (even parity), or “odd”(odd parity)• Display F : “Cr-LP dlmt”

RS-232C communication delimiter set value
Select either “Cr-LF” / “Cr-”RS-232C• Setting canceling method·

After selecting respective setting items, press the ENTER key. The set values are written in
the memory (nonvolatile).

 Canceling remote state
In the GPIB remote state, the “GPIB RMT” lamp in the left center of front panel lights up.
LOCAL

key is pressed, the remote state is cancelled and the operation from theAt this time, if
GPIBfront panel is enabled. However, the LOCAL key is inactive in the local lockout state.
LOCAL

key to cancel the remote state.

Also, in the RS-232C remote state, similarly press theGPIB

2721/2722

7-3

REMOTE CONTROL FUNCTION

7.2 GPIB interface
Through the GPIB interface of this product, almost all settable parameters can be set remotely.
Also, the settings and measured data can be sent to an external unit.
The codes used are the text format codes (ASCII codes) only.
LOCAL

The GPIB remote state is cancelled by pressing the

key on the front panel.
GPIB

 GPIB interface functions
The GPIB interface functions of this product are as listed in “Table 7-1 GPIB interfacefunctions”.
Table 7-1

GPIB interface functions

Functions

SubsetDescription

Source Handshak

SH1

All functions of transmission handshake provided

Acceptor Handshake

AH1

All functions of reception handshake provided

TalkerT6

Basic talker function, serial poll, talker cancel by
MLA

Listener

L4

Basic listener function, listener cancel by MTA

Service Request

SR1

All functions of service request provided

Remote/Local

RL1

All functions of remote/local provided

Parallel Poll

PP0

Parallel poll function not provided

Device Clear

DC0

Device clear function not provided

Device Trigger

DT1

All functions of device trigger provided

Controller

C0

Controller function not provided

 Device driver
The bus driver specifications of this product are as listed in “Table 7-2 Device driver
specifications”.
Table 7-2

Device driver specifications

Signal line nameDIO1−8
NDAC
NRFD
SRQ
DAV
EOI

7-4

Specification

Open collector

3 state2721/2722

REMOTE CONTROL FUNCTION

 Outline of GPIB operations
The output of GPIB communication operations of this product is as described below.
Though the outline of the operations in the cases of listener and talker is listed below, see “7.5Command List” for further information on commands.

z In the case of listenerClassification

Description

Measurement mode setting

The number of calculation items is set

Measurement item setting

The function and element to be displayed are set

Measured data query

For reading the measured data

Measurement condition setting

Sync signal, average-related items, measurementmode, etc. are set

Counter setting

The counter-related items are set and operated

Integration setting

The integration-related items are set and operated

Communication setting

The communication-related items are set andoperated

System-related setting

The time and serial number are queriedz In the case of talker
Classification

Description

Transmission of measurementmode setting

The setting of the number of calculation items istransmitted

Transmission of measurement item
setting

The settings of item and phase being displayed
are transmitted

Transmission of measured data

Measured data is transmitted

Transmission of measurement
condition setting

The settings of sync signal, average-related
items, measurement mode, etc. are transmitted

Transmission of counter setting

The setting of counter-related items is transmitted

Transmission of integration setting

The setting of integration-related items istransmitted

Transmission of communication
setting

The setting of communication-related items istransmitted

Transmission of system-related
setting

The time and serial number are transmitted

2721/2722

7-5

REMOTE CONTROL FUNCTION

 Service Request (SRQ)
This product sends the SRQ command under the condition mentioned below. Among them, tosend SRQ at the completion of count, further send the SRQ command to write the data to theservice request enable register.
• After “GET” was received, when the measurement finished
See the “Group Execute Trigger”.
• When count completed
At the completion of count, SRQ is sent, but in the train mode, SRQ is not sent.
The controller, when SRQ is received, should perform the serial poll to designate the interrupt
generating source (this device) as a talker.
The status bytes that are output during the serial poll are as follows:
BIT

DIO8

DIO7

DIO6

DIO5

DIO4

DIO3

DIO2

DIO1

Contents

0

RQS

0

MEA

0

CNT

0

0

RQS:

1 when service request is made

MEA:

1 when service request is made at completion of measurement

CNT:

1 when service request is made at completion of count Group Execute Trigger (GET)
When GPIB address command GET is received, this product sends SRQ to the controller when
the next measurement completed.
If the GET command is used, be sure to read the measured data after the controller received
the SRQ.

 Go To Local (GTL)
When GPIB address command GTL is received, this product turns off the GPIB RMT lamp on
the front panel to activate the local state.

 Local Lock Out (LLO)
When GPIB universal command LLO is received, this product disables the LOCAL key on thefront panel.

7-6

2721/2722

REMOTE CONTROL FUNCTION

7.3 RS-232C interface
Through the RS-232C interface of this product, almost all settable parameters can be set
remotely. Also, the settings and measured data can be sent to an external unit, and the codesused are the text format codes (ASCII codes).
Even with the RS-232C interface, the remote state can be set with the RSM:RMT command. In
this case, the remote state is cancelled if the LOCAL key on the front panel is pressed.

 RS-232C interface specifications
The RS-232C interface specifications of this device are as follows:
•
•
•
•
•
•
•
•

Communication method : Half duplex
Synchronizing method : Asynchronous
Baud rate: 600, 1200, 2400, 4800
Start bit
: 1 bit fixed
Data length: 8 bits fixed
Parity: None, Even (EVEN), Odd (ODD)
Stop bit: 1 bit, 2 bits
Received buffer length : 256 bytes

 Connection of RS-232C cables
When this product is connected to the host computer, connect as shown below:

FG
TxD
RxD
RTS
CTS
DSR
SG
DTR

Pin No.

Pin No.

1

1

2

2

3

3

4

4

5

5

6

6

7

7

20

20

Figure 7-1

2721/2722

FG
TxD
RxD
RTS
CTS
DSR
SG
DTR

Connection of RS-232C cables

7-7

REMOTE CONTROL FUNCTION

 Connection of RS-232C interface
z Connector and signal names#4:RTS#3:RxD#5:CTS#6:DSR#7:SG#11, #13, and #14 areconnected to GND.
Other pins are notused.

#2:TxD#1:FG#20:DT
Figure 7-2

RS-232C Connector(RS-232C connector: DBSP-JB25S or equivalents)
Table 7-3

RS-232C Connector pin assignment

Pin No.

Name

Symbol

1

Frame GroundFG

Connect to the case2

Transmitted Data

TxD

Data output

OUT

3

Received Data

RxD

Data input

IN

4

Request to Send

RTS

“H” at data output, and “L” atcompletion

OUT

5

Clear to Send

CTSWith “H”, data output is readyIN

6

Data Set ReadyDSR

At “H”, data output is readyIN

7

Signal GroundSG

Connect to signal power supply

20

Data Terminal ReadyDTR“H” when data reception is ready, or“L” when data reception is not ready

7-8

Description

Direction

OUT

2721/2722

REMOTE CONTROL FUNCTION

 Outline of RS-232C operations
The outline of data reception and data transmission is as mentioned in the following tables.
For further information on the commands, see “Table 7-4 Command list (1/2)” and “Table 7-5
Command list (2/2)”.

z Data reception
Classification

Description

Measurement mode setting

The number of calculation items is set

Measurement item setting

The function and element to be displayed are set

Measured data query

For reading the measured data

Measurement condition setting

Sync signal, average-related items, measurementmode, etc. are set

Counter setting

The counter-related items are set and operated

Integration setting

The integration-related items are set and operated

Communication setting

The communication-related items are set andoperated

System-related setting

The time and serial number are queriedz Data transmission
Classification

Description

Transmission of measurementmode setting

The setting of the number of calculation items istransmitted

Transmission of measurement item
setting

The settings of item and phase being displayed
are transmitted

Transmission of measured data

Measured data is transmitted

Transmission of measurement
condition setting

The settings of sync signal, average-related
items, measurement mode, etc. are transmitted

Transmission of counter setting

The setting of counter-related items is transmitted

Transmission of integration setting

The setting of integration-related items istransmitted

Transmission of communication
setting

The setting of communication-related items istransmitted

Transmission of system-related
setting

The time and serial number are transmitted

2721/2722

7-9

REMOTE CONTROL FUNCTION

7.4 Program Codes
 Program codes
The program codes are stored in the input buffer temporarily, and they are interpreted andexecuted in order of reception when a delimiter is received.
The input buffer capacity is 256 characters (256 bytes), and the null (00H) and a delimiter are
not stored in the input buffer. When program codes exceeding 256 characters are received, up
to 256 characters are executed, and the subsequent program codes are cleared and an error
occurs. Also, if unspecified header or parameter exists in the program codes, it is treated as anerror and the input buffer is cleared and the subsequent program codes are not executed.
When interpretation of program codes and execution of valid commands finished, the input
buffer is cleared and the next input becomes ready.
A program code is composed of a header and a parameter. The syntax of a program code isshown below.

Header：

Data

Delimiter，
Parameter；

When multiple program codes are sent at a time, insert a semicolon (;) between program codes.
A program code is classified into a “setting message” that makes setting and a “query message”
that queries the state and set value.

Program code

Setting message
Query message

 Setting message
The setting message has the format as mentioned below. In this example, the FUNCTION and
ELEMENT are set to “voltage V1 on Display A, current A1 on Display B, active power W1 on
Display C, reactive power on Display D, phase A-B on Display E, and frequency Hz on Display
F”.

D1A : VL1 ; D1B : AM1 ; D1C : WT1 ; D1D : VR1 ; D1E : DA0 ; D1F : HZ0
a b c d a
c
a
c
a
c
a
c
a
c
a: Header. It is composed of three alphanumeric characters, and uppercase or lowercase
characters can be used.
b: Character for visibility, and a space may be used.
c: Parameter. It is composed of alphanumeric characters, and the number of characters varydepending on the command.
d: Semicolon to delimit plural setting messages

7 - 102721/2722

REMOTE CONTROL FUNCTION

 Query message
The query message is a command attached with “?” at the beginning of a program code and it
is a program code to query the measured data, state, or set value to this product.
After the query message is sent, the result is output if the device is designated as a talker.
When program codes that contain multiple queries are received at a time, the productresponds to the last query. Also, when a new query message is received without being
designated as a talker after the query, the response message to the previous query is cleared
and a response message to new query is prepared.

Header

Data

Delimiter，
Parameter

The header of response message to the query can be turned on/off by the setting message“HDR:1” / “HDR:0”. It is turned on (header is output) at the power on.

2721/2722

7 - 11REMOTE CONTROL FUNCTION

7.5 Command List
External communication commands are as listed below.
For details of individual commands, see “7.6 Description of Individual Commands”.
Table 7-4
Classification
Measured items

CommandPage

Phase voltage measurement?Dna :AMe:WTeCurrent measurement
Line voltage measurement
3:V31)
Active power measurement:VAe

Apparent power measurement:VRe

Reactive power measurement:PFe

Power factor measurement:DFe

Measurement of phase difference between V and A

:DSe
:DWe

p.7-16(1:V12,

Counter display:I1e

Impedance (V/A) measurement:I3e

Impedance (V/(√3×A) ) measurement:ISe

Impedance (V/(2×A×sinφ) ) measurement:HZ0

Frequency measurement:WHe

Integration active power measurement:AHe

Integration voltage measurement:VHe

Integration reactive power measurement:DC0
SYC :e?SYC
DSP :n?DSPMSR :n?MSR
WRG :n?WRG
HLD :{n,(E,n)}?HLD
AVG :{0,1,(S,m,w)}?AVG
RNG :{0,1,(el,n)}?RNG
SCL :{0,1,(el,data)}?SCL

2:V23,

Measurement of phase difference of element
based on reference phase
Measurement of phase difference between
voltage lines (1:V12, 2:V23, 3: V31)

:CN0

:DA0

7 - 12

Description

Dna :VLe:VVe

Measurement
condition setting

Command list (1/2)

Measurement of phase difference between
Displays A and B
Measurement of phase difference between
Displays C and D
SYNC signal setting/queryp.7-19Display number setting/queryp.7-16

Measurement mode setting/queryp.7-18Wiring type setting/queryp.7-19Hold on/off setting, hold function setting by trip
p.7-17
input/query
Average on/off setting, count setting/queryp.7-14

Range mode setting, range switching/queryp.7-18

Scaling on/off setting, scaling factor setting/queryp.7-182721/2722

REMOTE CONTROL FUNCTION

Table 7-5
Classification
Measured datareading
Measurement
mode
Counter setting

Command list (2/2)

Command

Description

Page?INP :nMeasured data /queryp.7-17?STS
CLC :m?CLC
CNM :m,{n,nnn}?CNM

Input state queryp.7-19Calculation mode setting/queryp.7-15Counter setting, chattering time setting/ queryp.7-15Counter resetp.7-15Counter chattering eliminating setting/ queryp.7-14

Counter start signal setting/ queryp.7-15Counter trip signal setting/ queryp.7-16Counter data queryp.7-15Integrate operation setting/queryp.7-17

Integrate mode setting, time setting/queryp.7-17Header setting/queryp.7-16

GPIB SRQ status setting/queryp.7-19RS-232C remote/local switching/queryp.7-18Internal clock setting/queryp.7-15Gain calibration/queryp.7-14

Offset calibration/queryp.7-14Model name number setting/queryp.7-18

Serial number setting/queryp.7-19

CRS :0
CCT :n?CCT
CST :cb?CST
CTP :cb?CTP

Integrate setting

Communication
setting

System setting?CDT
IDO :{SR,SP,RS}?IDO
IMD :m,time
?IMD
HDR n
?HDR
SRQ nnn?SRQ
RSM aaa?RSM
CLK :data,time?CLK*CBG el,±nn.nnn?CBG*CBO el?CBO*MDL nnnn?MDL*SRL :mm,ssssss?SRL*Note: Do not execute the CBG, CBO, and MDL commands. The device may not operate
normally.

2721/2722

7 - 13REMOTE CONTROL FUNCTION

7.6 Description of Individual Commands
This section describes in detail the commands. The commands are listed in alphabetical order.
Also, the symbol used in the description has a meaning as mentioned below.
{ / }: Either one of the braced options is selected AVG/?AVG
Description : Sets/queries the average function and average count.
Parameter: Specify the average function ON/OFF and specify the average count. (0/1/S,mm,ww)
0 : Average function OFF
1 : Average function ON
S,mm,ww : Specify the average countmm : Moving average count {01,02,04,08,16,32,64}
ww : Wavenumber average count {01,02,04,08,16,32}

Response: Average function ON/OFF state and average count “mm,ww” is output.
AVG:{OFF/ON_},AV:mm,ww

 CBG/?CBG
Description : Sets/queries the gain correction data. For the gain correction, only the range at the time when
the data is sent is corrected.
Parameter: Specify the set input and set the gain correction data (%).(el,±nn.nnn)
el : Specify the input {V1,V2,V3,V0,A1,A2,A3,A0}±nn.nnn : Gain correction data {-15.000% to +15.000%}
Specify the range when the content of gain correction data is queried (0 to 9)
0 : 1V,0.04A / 1 : 2.5V,0.1A / 2 : 5V,0.2A / 3 : 10V,0.4A / 4 : 20V,0.8A/ 5 : 40V,1.6A / 6 : 80V,3.2A / 7 : 160V,6.4A / 8 : 320V,12A / 9 :640V,24A

Response: The date and time when correction is made and the gain correction data in the specified range
are output.
CBG:yy/MM/dd,hh:mm,V1:±nn.nnn,V2:....,V3:....,V0:....,A1:....,A2:....,A3:....,A0:....

 CBO/?CBO
Description : Sets/queries the offset correction. For the offset, the measurement result at the time when thecommand is sent becomes the correction data, and only the range at that time is corrected.
Parameter: Specify the set input (el)el : Specify the input{V1,V2,V3,V0,A1,A2,A3,A0}
Specify the range when the content of offset correction data is queried (0 to 9)
0 : 1V,0.04A / 1 : 2.5V,0.1A / 2 : 5V,0.2A / 3 : 10V,0.4A / 4 : 20V,0.8A/ 5 : 40V,1.6A / 6 : 80V,3.2A / 7 : 160V,6.4A / 8 : 320V,12A / 9 : 640V,24A

Response: The date and time when correction is made and the offset correction data in the specified range
are output.
CBO:yy/MM/dd,hh:mm,V1:±nnnnn,V2:....,V3:....,V0:....,A1:....,A2:....,A3:....,A0:....

 CCT/?CCT
Description : Sets/queries the chattering eliminating function of the counter.
Parameter: Specify the counter chattering eliminating function ON/OFF (0/1)
0 : OFF
1 : ON

Response: The counter chattering eliminating function on/off state is output.
CCT:{OFF/ON_}

7 - 142721/2722

REMOTE CONTROL FUNCTION

 ?CDT
Description : Queries the measured data of the counter.
Parameter: NoneResponse: The measured data of the counter is output. The type of data varies depending on the countermode.
“CN1” denotes counter 1, “CN2” denotes counter 2, “C1X”, “C2X” denote maximum value ofcounters 1 and 2, and “C1N”, “C2N” denote minimum value of counters 1 and 2.
Counter in non-operating state : CDT:NOTCNTCounter in single mode

: CN1:±n.nnnnE±nn

Counter in dual mode

: CN1:±n.nnnnE±nn,CN2:±n.nnnnE±nn

Counter in multi mode

: CN1:±n.nnnnE±nn,C1X:±n.nnnnE±nn,C1N:±n.nnnnE±nn,CN2:±n.nnnnE±nn,C2X:±n.nnnnE±nn,C2N:±n.nnnnE±nn

 CLC/?CLC
Description : Sets/queries the calculation mode.
This command is settable from remote control only. “A” is always set at the power on.
Parameter: Set the calculation mode (A/B)
A : Only the functions being displayed are calculated. Only the data of displayed items (6 items)
are sent.
B : The functions of all items are calculated. The data of 24 items are sent.

Response: The calculation mode state is output.
CLC:{A/B}

 CLK/?CLKDescription : Sets/queries the date and time of internal clock.
Parameter: Specify date and time (yy/MM/dd,hh:mm)

Response: The date and time of internal clock are output.

yy/MM/dd,hh:mm : Year month day, hour minute
CLK:yy/MM/dd,hh:mm:ss

 CNM/?CNM
Description : Sets/queries the counter mode.
Parameter: Specify the Interval mode, One Shot mode, external reset ON/OFF, threshold value of trip
input, chattering time, and switch the counter operation.
(I,{0,1,2} / O,{0,1} / R,{0,1} / T,{0,1,2} / C,nnn / M, {0,1})
I,{0,1,2} : Interval mode setting

0= Single (SNGL), 1= Dual (DUAL), 2= Multi (MULT)

O,{0,1}: One shot mode setting

R,{0,1}: Set the external reset function

0= One shot (ONESH), 1= Train (TRAIN)
0=OFF, 1=ON

T,{0,1,2} : Set the trip input voltage threshold value
C,nnn: Set the chattering time

M,{0,1} : Switch the counter operation
Response

0=2.5V, 1=8V, 2=50V

nnn: 001 to 125(ms)0= One shot (ONESH), 1= Interval (INTVL): The counter mode state and the setting content of each mode are output.
CNM:I/{SNGL/DUAL/MULT},O/{ONESH/TRAIN},R/{OFF/ON_},T/{2.5V/8.0V/50.V},C/nnn,M/{ONESH/INTVL} CRS
Description : Resets the counter.
Parameter: None CST/?CST
Description : Sets/queries the counter start input format and operation mode.
Parameter: Specify the start input format and operation mode. ({C,V}{B,M})
C : Specify contact input / V : Specify voltage input
B : B-M / M : M-B(“B” : Contact open or voltage High, “M” : Contact closed or voltage Low)

Response: The counter start input format and operation mode setting state are output.
CST:{C/V},{B/M}

2721/2722

7 - 15REMOTE CONTROL FUNCTION CTP/?CTP
Description : Sets/queries the counter trip input forma and operation mode.
Parameter: Specify the trip input format and operation mode. ({C,V}{B,M})
C : Specify contact input / V : Specify voltage input
B : B-M / M : M-B(“B” : Contact open or voltage High, “M” : Contact closed or voltage Low)

Response: The counter trip input format and operation mode setting state are output.
CTP:{C/V},{B/M} Dna/?Dna
Description : Sets/queries the FUNCTION and ELEMENT.
Exchange the character “n” in the command with STORE/RECALL number (1,2,3,4).
Exchange the character “a” in the command with the display location (A,B,C,D,E,F).
Parameter: Set the FUNCTION and ELEMENT. However, the display location of FUNCTION except voltage
and current is limited. “e” specifies the element, and unless otherwise specified, 0-3 specifies
the input phase, and 4 specifies “Σ”.
VLe

: Phase voltage

AMe: Current

VVe: Line voltage / 1 : V12, 2 : V23, 3 : V31

WTe: Active power [A,B,C,D only]

VAe: Apparent power [A,B,C,D only]VRe: Reactive power [A,B,C,D only]PFe: Power factor [A,B,C,D only]DFe: Between current and voltage phase difference [A,B,C,D only]DSe: Phase difference of element based on reference phase. Reference input is SYNC input. [A,B,C,D only]

DWe

0 : V0, 1 : V1, 2 : V2, 3 : V3, 4 : A0, 5 : V1, 6 : V2, 7 : V3
: Phase difference between voltage lines／1 : V12, 2 : V23, 3 : V31 [A,B,C,D only]

CN0: Counter display [E only]

I1e: Impedance ( V / A ) [E only]

I3e: Impedance ( V / (ISe

Response

3 A) ) [E only]: Impedance ( V / (2 A sin φ ) ) [E only]

HZ0: Frequency [F only]

WHe: Integration active power [F only]

AHe: Integration current [F only]

VHe: Integration reactive power [F only]

DA0: Phase difference between Displays A and B [E only]

DC0: Phase difference between Displays C and D [F only]: The FUNCTION/ELEMENT state of measurement displayed is output.
Dna:{VLe/AMe/VVe/WTe/VAe/VRe/DFe/DSe/DWe/CN0/I1e/I3e/ISe/HZ0/WHe/AHe/VHe/DA0/DC0}

 DSP/?DSP
Description : Sets/queries the STORE/RECALL number.
Parameter: Specify the STORE/RECALL number. (1 to 4)
In the calculation mode A, the measurement, display, and response data are switched.
In the calculation mode B, the display data is switched.

Response: The STORE/RECALL number state is output.
DSP:{1/2/3/4}

 HDR/?HDR
Description : Sets/queries the header ON/OFF of response to the query.
Parameter: Header ON/OFF (0 / 1)
0 : OFF
1 : ON

Response: Response header ON/OFF setting state is output.
HDR:{OFF/ON_}

7 - 162721/2722

REMOTE CONTROL FUNCTION

 HLD/?HLDDescription : Sets/queries the display hold and the hold function by trip input.
Parameter: Specify the hold ON/OFF and set the hold function by trip input. (0 / 1 / E,{0,1})
0 : Cancel the hold (OFF)1 : Set the hold (ON)E,{0,1} : Hold function by trip input

Response

0 = Invalid (OFF), 1 = Valid (ON): The hold state and the setting of hold function by trip input are output.
HLD:{OFF/ON_},EXT:{OFF/ON_} IDO/?IDO
Description : Sets/queries the integration operation.
Parameter: Specify the integrating operation. (SR / SP / RS)
SR : Start the integrating operation
SP : Stop the integrating operation
RS : Integrating data reset

Response: The integrating operation state and integrated time state (hhh: hour, mm: minute) are output.
IDO:{SR/SP/RS},hhh.mm

 IMD/?IMD
Description : Sets/queries the integrate mode.
Parameter: Specify the Integrate mode, integrated time, and integration start and stop time.
(M / T,timer / R,starttime,endtime)
M : Manual operation
T : Timer operation
timer : timer operation (hhh: mm: Specify hour, mm: minute)
R : Real time integrating operation
starttime : Specify the start time (yy/MM/dd,hh:mm : Specify year month day, hour minute)endtime : Specify the end time (yy/MM/dd,hh:mm : Specify year month day, hour minute,same as startime)

Response: The Integrate mode setting state and the setting content of each mode are output.
IMD:M
IMD:T,timer
IMD:R,starttime,endtime

 ?INP
Description : Queries the measured data.
Parameter: Specify the transmitted data (Parameter varies depending on the calculation mode A or B)
In the calculation mode A (only the displayed function is calculated)
Parameter none, Measurement result being displayed is sent
In the calculation mode B (all items are calculated)
0 : Send the measurement result being displayed
1,2,3,4 : Send only the measurement result of the specified STORE/RECALL number
A : Send the measurement result of all 24 items

Response: Measured data specified by the parameter are output.
dna:±n.nnnnE±nn,dnb:±n.nnnnE±nn,dnc:±n.nnnnE±nn,dnd:±n.nnnnE±nn,dne:±n.nnnnE±nn,dnf:±n.nnnnE±nn[/d2a:±n.nnnnE±nn,d2b:±n.nnnnE±nn,d2c:±n.nnnnE±nn,d2d:±n.nnnnE±nn,d2e:±n.nnnnE±nn,d2f:±n.nnnnE±nn/d3a:±n.nnnnE±nn,d3b:±n.nnnnE±nn,d3c:±n.nnnnE±nn,d3d:±n.nnnnE±nn,d3e:±n.nnnnE±nn,d3f:±n.nnnnE±nn/d4a:±n.nnnnE±nn,d4b:±n.nnnnE±nn,d4c:±n.nnnnE±nn,d4d:±n.nnnnE±nn,d4e:±n.nnnnE±nn,d4f:±n.nnnnE±nn]“dna,dnb,dnc,dnd,dne,dnf” specify the FUNCTION/ELEMENT of the measurement. Refer to the “Dna”
parameter. If the data of all 24 items are output, the data in [] continue.

The header “INP” is not attached to the above data even if the header ON is specified.

2721/2722

7 - 17REMOTE CONTROL FUNCTION MDL/?MDL
Description : Sets/queries the model name number (specify).
Parameter: Specify the model name number. (2721 / 2722)

Response: The model number, program version, and with/without 2725 input unit are output.

[Note] Never change the model number.
MDL:{2721/2722},n.nn_a,ELMT{123_/1230}
n.nn_a : Program version number
123_ : Without 2725 input unit
1230 : With 2725 input unit

 MSR/?MSR
Description : Sets/queries the measurement mode.
Parameter: Specify the measurement mode. (0 / 1)
0 : AC mode
1 : DC mode

Response: The measurement mode state is output.
MSR:{AC/DC} RNG/?RNG
Description : Sets/queries the range.
Parameter: Select either manual range or auto range, and specify the range. (0 / 1 / el,n)However, therange is ineffective in the auto range even if it is specified.
0 : Manual range
1 : Auto range
el : Specify the input {V1,V2,V3,V0,A1,A2,A3,A0}
n : Specify the range {0 to 9}
0 : 1V,0.04A / 1 : 2.5V,0.1A / 2 : 5.00V,0.20A / 3 : 10.0V,0.40A / 4:20V,0.8A/ 5 : 40V,1.6A / 6 : 80V,3.2A / 7 : 160V,6.4A / 8 : 320V,12A / 9 : 640V,24A
Response: The range setting state and range state are output.
mgV is a voltage range (1V to 640V), and mgA is a current range (0.04A to 24V / 0.001A to 0.01V /2A to 20V / 20A to 200V).
RNG:{OFF/ON_},V1:rngV,V2:rngV,V3:rngV,V0:rngV,A1:rngA,A2:rngA,A3:rngA,A0:rngA RSM/?RSM
Description : Sets/queries the remote / local for RS-232C interface.
Parameter: Select remote / local for RS-232C interface.
RMT : Select remote state
LCL : Change from remote state to local state

Response: The remote / local state for RS-232C interface is output.
RSM:{RMT,LCL} SCL/?SCL
Description : Sets/queries the scaling function and scaling factor.
Parameter: Specify the scaling function ON/OFF, scaling mode setting, and scaling factor.
(0 / 1 / el,+n.nnnnE±nn)
0 : Scaling function OFF
1 : Scaling function ON
el : When same factor is set for all items, specify voltage or current: {VA,AA} / +n.nnnnE±nn : factor
When individual factors are set, specify the input {V1,V2,V3,V0,A1,A2,A3,A0} / +n.nnnnE±nn: factor

Response: The scaling function on/off state and the setting content of scaling are output.
When same factor is set :SCL:{OFF/ON_},V:±n.nnnnE±nn,A:±n.nnnnE±nn
When individual factors are set:
SCL:{OFF/ON_},V1:±n.nnnnE±nn,V2:±n.nnnnE±nn,V3:±n.nnnnE±nn,V0:±n.nnnnE±nn,
A1:±n.nnnnE±nn,A2:±n.nnnnE±nn,A3:±n.nnnnE±nn,A0:±n.nnnnE±nn

7 - 182721/2722

REMOTE CONTROL FUNCTION SRL/?SRL
Description : Sets/queries the last 6 digits of a serial number. Do not change the setting.
Parameter: Specify a serial number. (MF,mmmmmm / el,nnnnnne)[Note] Never change the setting.
MF : Specify the serial number of the main frame.
mmmmmm : Serial number (100000 to 999999) last 6 digits
el : Specify the input {V1,V2,V3,V0,A1,A2,A3,A0}
nnnnnne : Serial number (1000000 to 9999993) 7digits[Note] The serial number of standard input unit for 2721 or 2722 is “last 6 digits of serial number of themain frame + element number”. The serial number assigned to the 2725 input unit (optional) is notapplicable here.

Response: All serial numbers contents are output.
SRL:mmmmmm,V1:nnnnnn1,V2:....,A1:nnnnnn1,....

 SRQ/?SRQ
Description : Sets/queries the service request enable register. The service request is made even if it is not
set with the command, when the measurement finished after the Group Execute Trigger wasreceived.
Parameter: Set the service request enable register.
0 : Service request is not made at the completion of count4 : Service request is made at the completion of countResponse: The setting of service request enable register is output.
SRQ:nnn

 ?STS
Description : Queries the input state.
As the input states, there are “range data state of each input”, “synchronous or asynchronous
state of sync input” and “error number”.
Parameter: NoneResponse: The input state is output.
STS:RNG:vvvv_aaaa,TRG,ERR:nn
vvvv_aaaa : The range state of each input is indicated.
vvvv indicates the voltage V1,V2,V3,V0, and aaaa indicates the current A1,A2,A3,A0 in
this order.
0 to 9 is a range number.
0 : 1V,0.04A / 1 : 2.5V,0.1A / 2 : 5.00V,0.20A / 3 : 10.0V,0.40A/4:20V,0.8A/ 5 : 40V,1.6A / 6:80V,3.2A / 7 : 160V,6.4A / 8 : 320V,12A / 9 : 640V,24A
For under range, “U” is given instead of range number, or for over range, “D” is given.
TRG: Synchronous state is indicated. “TRG” indicates synchronous state, and “NTG”

ERR:nn: A communication error number is indicated. The error numbers are as follows.

indicates asynchronous state.
[30] Header error / [31] Parameter error / [32] Buffer over error[40] Parity error / [41] Overrun error / [42] Flaming error[43] Break detection error

 SYC/?SYC
Description : Sets/queries the synchronous signal.
Parameter: Specify the synchronous signal. (0 to 8)

Response: The synchronous signal state is output.

0 : V0 / 1 : V1 / 2 : V2 / 3 : V3 / 4 : A0 / 5 : A1 / 6: A2 / 7 : A3 / 8 : LINE
SYC:{V1/V2/V3/V0/A1/A2/A3/A0/LINE} WRG/?WRG
Description : Sets/queries the wiring method.
Parameter: Specify the wiring method. (1 to 4)

Response: The wiring method setting state is output.

1 :1 φ2W(1f2W) / 2 : 1φ3W(1f3W) / 3 : 3φ3W(3f3W) / 4 : 3φ4W(3f4W)
WRG:{1f2W/1f3W/3f3W/3f4W}

2721/2722

7 - 19REMOTE CONTROL FUNCTION

7.7 Sample Programs
The GPIB and RS-232C sample programs are shown below.
This is a case that uses PC-9801 (made by NEC) as a controller.

 GPIB sample program
With the SYNC signal V1, “voltage V1, current A1, active power W1, apparent power VA1,
voltage to current phase difference degAB, sync input frequency Hz” are set for the element 1
input, and the measured data are read.

1010 '**********************************************************
1020 '*
FOR 2721/2722 POWER MULTIMETER*
1030 '*GPIB SAMPLE PROGRAM*
1040 '**********************************************************
1050 'SAVE "2721IBCK.BAS",A1060 ADR=7'GPIB address:71070 CMD DELIM=0'Delimiter setting :CR+LF
1080 ISET IFC,100'Clear the interface
1090 ISET REN'Set the interface to remote
1100 FOR I=0 TO 100:NEXT I'Waite1110 ' Set measurement conditions
1120 PRINT@ ADR;"MSR:0"'Measurement mode :AC
1130 PRINT@ ADR;"DSP:1"'Display number:[1]1140 PRINT@ ADR;"SYC:1"'Synchronous signal setting:V11150 PRINT@ ADR;"AVG:1"'Average:ON1160 PRINT@ ADR;"RNG:1"'Range setting:AUTO ON
1170 PRINT@ ADR;"SCL:0"'Scaling:OFF
1180'FUNCTION setting :V1,A1,W1,VA1,degAB,Hz
1190 PRINT@ ADR;"D1A:VL1;D1B:AM1:D1C:WT1;D1D:VA1;D1E:DA0;D1F:HZ0"1200 ' Time waiting
1210 FOR I=0 TO 50000!:NEXT I
1220 ' End after 5-time measurements
1230 FOR K=1 TO 51240 ' Query the measured data
1250
PRINT@ ADR;"?INP"
1260 ' Read the data
1270
INPUT@ ADR;DA$,DB$,DC$,DD$,DE$,DF$
1280
PRINT "K=";K1290
PRINT DA$,DB$,DC$,DD$,DE$,DF$ ' Display the read data
1300 ' Time waiting
1310
FOR I=0 TO 50000!:NEXT I
1320 NEXT K
1330 ' LOCAL
1340 IRESET REN' Cancel the remote
1350 END

7 - 202721/2722

REMOTE CONTROL FUNCTION RS-232C sample program
With the SYNC signal V1, “voltage V1, current A1, active power W1, apparent power VA1,
voltage to current phase difference degAB, sync input frequency Hz” are set for the element 1
input, and the measured data are read.

1010 '**********************************************************
1020 '*
FOR 2721/2722 POWER MULTIMETER*
1030 '*
RS-232C SAMPLE PROGRAM*
1040 '**********************************************************
1050 'SAVE "2721RS_1.BAS",A1060 OPEN "COM1:N81NN" AS #1'Communication port open 8BIT,1BIT,NON
1070 FOR T=0 TO 1000:NEXT T'Processing time waiting
1080 ' Set measurement conditions
1090 PRINT #1,"HLD:1"'
1100 FOR T=0 TO 1000:NEXT T'Processing time waiting
1110 PRINT #1,"?HLD"'
1120 LINE INPUT #1,RCV$:PRINT RCV$
1130 PRINT #1,"MSR:0"'Measurement mode :AC1140 PRINT #1,"?MSR"'Measurement mode :AC1150 LINE INPUT #1,RCV$:PRINT RCV$
1160 PRINT #1,"DSP:1"'Display number:[1]1170 PRINT #1,";?DSP"
1180 LINE INPUT #1,RCV$:PRINT RCV$
1190 PRINT #1,"SYC:1"'Synchronous signal setting:V1
1200 PRINT #1,"?SYC"
1210 LINE INPUT #1,RCV$:PRINT RCV$
1220 PRINT #1,"RNG:1"'Range setting :AUTO ON
1230 PRINT #1,"?RNG"
1240 LINE INPUT #1,RCV$:PRINT RCV$
1250 PRINT #1,"SCL:0"'Scaling:OFF
1260 PRINT #1,"?SCL"
1270 LINE INPUT #1,RCV$:PRINT RCV$
1280 'FUNCTION Setting:V1,A1,W1,VA1,degAB,Hz
1290 PRINT #1,"D1A:VL1;D1B:AM1:D1C:WT1;D1D:VA1;D1E:DA0;D1F:HZ0"1300 PRINT #1,"HLD:0"'1310 FOR T=0 TO 1000:NEXT T'Processing time waiting
1320 PRINT #1,"?HLD"'
1330 LINE INPUT #1,RCV$:PRINT RCV$
1340 FOR T=0 TO 10000:NEXT T'Processing time waiting
1350 ' Time waiting
1360 FOR I=0 TO 50000!:NEXT I 'Processing time waiting
1370 'End after 50000000-time measurements
1380 FOR K=1 TO 5E+06
1390 ' Query the measured data
1400 PRINT "K=";K1410 *HOLD
1420 PRINT #1,"HLD:1"
1430 FOR T=0 TO 10000:NEXT T'Processing time waiting
1440 PRINT #1,"?HLD"
1450 LINE INPUT #1,RCV$:PRINT RCV$
1460 IF MID$(RCV$,5,3)="ON_" THEN *HOLD
1470 PRINT #1,"?INP"
1480 ' Read the data
1490 INPUT #1,DA$,DB$,DC$,DD$,DE$,DF$
1500 PRINT DA$,DB$,DC$,DD$,DE$,DF$ 'Display the read data
1510 PRINT #1,"HLD:0;?HLD"'
1520 LINE INPUT #1,RCV$:PRINT RCV$
1530 ' Time waiting
1540 FOR I=0 TO 50000!:NEXT I
1550 NEXT K
1560 CLOSE 1'Communication port close1570 END

2721/2722

7 - 21REMOTE CONTROL FUNCTION RS-232C supplementary description
z Receivable section
The RS-232C interface of the 2721/2722 can receive data when “Data Terminal Ready(DTR)” is in “H” state.
The “Data Terminal Ready (DTR)” signal is as shown below.
The data should be sent from the host in a section of 110ms shown below.
Reception allowed
Data Terminal Ready
Reception prohibited

50ms

15ms

330ms*1

110ms

The conditions are “waveform averaging count: 8 times, frequency: 50Hz”.
In the reception prohibited section, the “voltage/current waveform is reading”. The initial
50ms is for checking the range, and accordingly if the range is changed, the range check isrepeated until the range is determined. The next 330ms is for reading the waveform data,
and thus it varies if the “waveform averaging count” is changed. If the “waveform averaging
count” is set to 1 or the average function is turned off, 330ms*1 varies to 50ms.
During the time that the reception processing is executed after a command was received,
the “Data Terminal Ready” is placed in low state to prohibit the reception of next command.
During the prohibited period, do not send a command.
For the command transmission interval, provide “50ms or more” with the “reception
allowed”.

z Communication method
When the setting or measured data are queried, set the “hold state” for smoothcommunication.
The command that sets the “hold state” is “HLD:1”. After setting, confirm that the holdstate has been set.
In the hold state, the reception is ready at all times, but an interval of more than 50ms
should be provided to transmit a command.

7 - 222721/2722

8. TROUBLESHOOTING AND MAINTENANCE

This chapter describes corrective actions, maintenance method, and calibration method when aproblem occurred in the “2721/2722 Power Multimeter”.
The “2721/2722 Power Multimeter” can be calibrated using the keys on the front panel.
However, the operation without reason may cause the internal correction data to be changed
and thus the accuracy not to be guaranteed. Accordingly, enough care should be taken whendate 2010/6/14(#93)

performing the calibration.

2721/2722

8-1

TROUBLESHOOTING AND MAINTENANCE

8.1 Troubleshooting Error display
At the power ON, the self-diagnosis is conducted, and if an error is found, an error number isshown on the Display D.
The description and its cause of the error number, and necessary action are mentioned below.
For the display when the power switch is turned on, see “3.1 Operation at Power ON” (p.3-5).
Table 8-1
Error display

Error display

Cause

Necessary action

DInternal RAM
read/write error

NF Corporation or one of ourrepresentatives

DInternal ROM sum
check error

NF Corporation or one of ourrepresentatives

 When the device appears to be a problem
When the device appears to be a problem, take corrective action mentioned below. After that, if
the device does not recover, please contact NF Corporation or one of our representatives.
Table 8-2
ProblemTroubleshooting (1/2)

Possible cause

Corrective action

Page

Check the supply voltage and thesetting of voltage selector switch

p.2-3

Power fuse has blown

Replace the fuse. (Be sure to use
the rated power fuse)p.2-4

Malfunction due to externalnoiseInstall the device in a place undergood environmental conditions

p.2-5

Power does not turn The power supply out ofon
rated range is used.

Front panel keys
are not accepted

The device is in remote state Press the LOCAL key to set the
local state

p.7-3

Keys are deteriorated

Please contact NF Corporation or
one of our representatives-

Response of panel
operation is slow

The wavenumber averagecount has been set to large
value (16 or 32)

Turn off the measurement averagefunction, or reduce the averagecount.

p.3-15

Error in displayed
data is large

When the measurementmode is AC, there is a DC
component (offset) in the
input signal

In the AC mode, the measurement
is performed with “true r.m.s.
value” and thus the DC
component is included in themeasured value. Try to measure
the DC component in the DC
mode.

p.3-178-2

p.6-5

2721/2722

TROUBLESHOOTING AND MAINTENANCE

Table 8-3
Problem
Displayed data iserroneous

Troubleshooting (2/2)

Possible cause

Corrective action

Page

Ambient temperature andhumidity are not within theaccuracy guarantee range

Use the device in the environment
within the specified range

p.2-5

The device is not warmed up After the power on, warm up theenoughdevice for more than 30 minutes

p.3-5

Cables are not connected
correctly

Connect the cables correctly

p.3-7

If AC signal is measured, set themeasurement mode to AC

p.3-15

Turn off the HOLD key lamp tocancel the hold statep.3-15The level and range of input
signal are not met

Turn on the AUTO key lamp to set
the auto range

p.3-15The scaling value is set andthe scaling function turnsonTurn off the SCAL key lamp toturn off the scaling function, or set
correct scaling value

p.3-15The device is affected by
noise

Input a signal not containing anoise, or install the device freefrom noise. Also, when making aquery through GPIB or RS-232C,
use a program such that a query ismade again if data is erroneous.

-

A signal that contains
harmonics is used as SYNC
signalAs SYNC signal, use the signal
not containing harmonics-

The SYNC signal level issmall and stablesynchronization is not
attained

Change the SYNC signal to thesignal having adequate levelp.3-15The input signal contains
much noise or it is unstable

Set the average count to a larger
value and turn on themeasurement average function

p.3-15

Unmeasurable NOTRIG occurs

The SYNC signal level issmall and stablesynchronization is not
attained

Change the SYNC signal to thesignal having adequate levelp.3-15

Setting by GPIB
cannot be madeAddress in a program does
not meet the setting of thisdeviceSet the address that meets thedevice setting

p.7-2

Same address as that ofother devices is set

Set the address different fromother products

p.7-2

Communication conditionsof RS-232C do not meet thecontroller

Set the communication conditionsof RS-232C, meeting the controller

p.7-3

Displayed data iserroneous(Query result by
Measurement mode setting
GPIB or RS-232C is is wrong
erroneous)
Display is held

Displayed data isunstable

Setting by RS-232C
cannot be made2721/2722

p.6-7

p.6-5

8-3

TROUBLESHOOTING AND MAINTENANCE

8.2 Outline of Maintenance Contents of maintenance work
To use the “2721/2722 Power Multimeter” under best conditions, appropriate maintenance isrequired.
• Operation inspection:

Check if the device operates correctly.

• Performance testing:

Check if the device respects the rated values.

• Adjustment, calibration:

If the rated values are not satisfying, NF Corporation will
make the necessary adjustment or calibration to restore
performance.

• Damage repair:

When the performance cannot be restored by the adjustment
or calibration, NF Corporation will identify the cause andlocation of the damage and will execute repairs.

This instruction manual describes how to easily proceed with “operation inspection andperformance testing”.
For more accurate “inspections, adjustments, calibration or repair”, contact NF Corporation or
one of our representatives.

 Backup battery for internal clock
The lithium battery used for internal clock is charged with small current while the power is
supplied to the device.
With full charge, the backup period is about 60 days. However, it varies depending on theambient temperature.
To charge the battery fully from empty state, the power must be supplied for about 60 hours.
After that, the battery is kept in full charge state if the power is supplied usually for morethan 20 hours. The battery is not over-charged even if the power is supplied continuously.。
The backup period is reduced when the lithium battery is deteriorated. In such a case, pleaseask for battery replacement to us. (Nonfree)
The battery life may be reduced without supplying the power for more than 6 months, andtherefore it is recommended that the power be supplied sometimes.

8-4

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TROUBLESHOOTING AND MAINTENANCE

8.3 Operation Inspection
 Confirmation before operation inspection
Before the operation inspection, confirm the following items:• Power voltage: Within rated voltage (AC100V, AC120V, AC220V, AC240V) ±10%

• Ambient temperature : 0 to 40°C
• Ambient humidity: 20 to 80%RH (no-condensing) Function checkz Check at power ON
At the power ON, check that no error is displayed. When an error is displayed, see “Table 81 Error display”.
z Check of main functions
Initially, set the device to the factory settings.
To initialize the device to the factory settings, turn on the power switch while pressing the
LOCAL key.
Then, enter the signal of same voltage and current values to respective voltage and current
input terminals to check that the measured values of similar extent are displayed.
For the phase measured value, since the same signal is entered, ±0.05deg is displayed as aphase difference between voltages, and ±0.1deg as a phase difference between currents.
Operate a key on the front panel to check that the display changes.
For the counter function, set the start and trip inputs as follows.
Input format: Contact input CONT (lamp ON)

Operation mode : M-B (lamp OFF)
Then, check that the counter starts when the start input is short-circuited, and then the
counter stops when the trip input is short-circuited.

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TROUBLESHOOTING AND MAINTENANCE

8.4 Calibration Operation Method
This product can be calibrated (offset calibration, gain calibration) by the panel operation.
NF ELECTRONICINSTRUMENTS

NF

2721

PEAK
OVER

POWER MULTIMETERFUNCTION

V1

V

A

W

VA

Var

PF

FUNCTION

deg

V

A

W

VA

Var

PF

SYNC

FUNCTION

deg

V

A

W

VA

Var

PF

POWER

V1

deg

V2

V2

V3

V3
V0
A1

ELEMENT

A

A2

1

2

3

W

VA

Var

1

2

3

0

Δ

B

Σ

Δ

ELEMENT
1

2

3

CNTR

V/A

V/3A

1

2

3

0

C

Σ

1

2

3

Hz

Wh

Ah

1

2

3

0

V0

Δ

ELEMENT

A1
A2

Σ

A3

A3

FUNCTION

A0
V

GPIB
SRQ

A

PF

FUNCTION

deg

V

A

Vsin

FUNCTION

A-B

V

A

Varh

A0

C-D

LIN
E

RMT
ERROR

NO
TRIG

RNG

ELEMENT

D

MODE
AC

STORE/RECALL
1

2

3

0

Δ

0

RESET

CONT

START

Δ

ELEMENTFΣCOUNTERWIRING
1Φ2W
1Φ3W

4

Δ

ELEMENT

E

Σ

0

Σ

INTEGRATE
START

STOP

B-M

HOLD

AVRG

M-B

HLD-MD

AVG-MD

B-M

RESET

RS-232C

TIME

HARM

INT-MD

CLOCK

HRM-MD

AUTO

SCAL

D/A

PRINT

RNG-MD

SCL-SET

DA-SET

PRT-MDSHIFTSHIFT+ENTER
Calibration

INTERVAL

DC

3Φ3W

3Φ4W

CNTMD

VOLT

CHAT

CONT

CAT-SET

VOLT

M-B

TRIP

ONE SHOT

ENTER

LOCAL

●
GPIB

Cursor keys
Calibration operation

 About calibration
This device stores the offset correction data and gain correction data in each range of each
input in the nonvolatile memory, and recalls them at the power ON for correction during
measurement.
Since the nonvolatile memory is not backed up by the battery, the correction data are notcleared even when the battery is discharged.
The correction data can be changed by the panel operation.
The offset calibration can be executed by pressing the keys on the front panel with the “voltage
input short-circuited and current input opened”. The reference voltage “0V” can be set easily
by short-circuiting the voltage input, and the reference current “0A” can be set by opening thecurrent input easily, and therefore the offset calibration can be executed even if the standard
instrument is not used.
For the gain calibration, the gain can be corrected within ±15% to the reference gain. However,
the gain calibration cannot be executed unless the standard “voltage and current generator” isused.

 Check before calibration
Before executing the calibration, check the following items.
• Warm-up time

: 2 hour or more

• Ambient temperature/ humidity : 23±5°C / 20 to 80%RH (no-condensing)• Power voltage

8-6:100V±2V

2721/2722

TROUBLESHOOTING AND MAINTENANCE

 Display of calibration mode
Press

SHIFT

+

ENTER

keys to activate the calibration mode.

The calibration mode display is as shown below. In this state, if any key is pressed, thecalibration mode is deactivated and the measurement mode is restored.
Press▲ , ▼ keys to set “oFSEt” or “GAin” on the Display F, and press the ENTER key toset each calibration mode.

55s

SET

1996

A

B

C

D

E

F

After the offset calibration or gain calibration, if the ENTER key is pressed, the display will be
as shown below:

SET

A

B

C

D

E

F

To set the correction data, press▲ ,▼ keys to set “StorE” on the Display F and press the

ENTER key. The correction data is stored in the nonvolatile memory.
To cancel the calibration, set “CAnCL” on the Display F and press the ENTER key, and turnoff the power switch once and then turn it on again.
Since the changed correction data is not stored in the nonvolatile memory, the correction data
before change is recalled by turning off and on the power switch.

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TROUBLESHOOTING AND MAINTENANCE

 Display of offset calibration mode
ELEMENT keys
Element switching

FUNCTION keys
Voltage/current switching

FUNCTION keys
Voltage/current range switching

FUNCTIONV

FUNCTION

A

SET
A

V
B

C

ELEMENT

1

2

3

0

mVdc
D

E

Display E
Voltage/current measured value (DC)F
Display F
Offset correction value (integer)• Display A : ”CALib SET”

Indicates the calibration mode.

• Display B : ”v1”

Indicates the input to be calibrated.

• Display C : ”rIndicates a range of the input shown on Display B.

1.0”• Display D : ”oFSEt”

Indicates the offset calibration mode.

• Display E : ”0.0471mVdc”

Measured value of the input (V1) shown on Display B
DC measurement is performed (simple average).

• Display F : ”00002”

The averaged result is displayed with integer value (raw dataof AD converter).
Value “00000” on Display F indicates the minimum offset state.

 Offset calibration setting method
To execute the offset calibration, follow the procedure mentioned below:(1) Short-circuit the voltage input and open the current input.
(2) Select the input of which offset is to be calibrated. For this purpose, select the voltage
input or current input with the FUNCTION keys on Display B, and the element with
ELEMENT keys.
(3) Select a range with the FUNCTION keys on Display C. The initial value is present range
setting. Usually, the auto range may be set. If nothing has been input, the minimum
range is set.
(4) Press▲ ,▼keys to execute the offset calibration. Press

repeatedly until the Display F shows “00000”. Pressing the

・

▲ ,

▼

keys

key resets thepresent correction data to zero. If cleared, the correction data becomes large.
(5) uccessively, to execute the calibration of all ranges, switch the range with the
FUNCTION keys on Display C and perform the operation in step (4).
(6) When the calibration up to the maximum range (voltage 640V, current 24A) finished,switch the input with the FUNCTION keys and ELEMENT keys on the Display B, andrepeat the operation in steps (3) and (4).
(7) When the offset calibration of the inputs and ranges finished, press the ENTER key tostore the offset correction data.

8-82721/2722

TROUBLESHOOTING AND MAINTENANCE

 Display of gain calibration mode
ELEMENT keys
Element switching

FUNCTION keys
Voltage/current switching

FUNCTION keys
Voltage/current range switching

FUNCTIONV

FUNCTION

A

SET

V

A

B

C

ELEMENT

1

2

3

0

V
D

E

%
F

Display E

Display F
Gain correction value (% display)

Voltage/current measured value (AC display)• Display A : ”CALib SET”

Indicates the calibration mode.

• Display B : ”v1”

Indicates the input to be calibrated.

• Display C : ”rIndicates a range of the input shown on Display B.

1.0”• Display D : ”GAin”

Indicates the gain calibration mode.

• Display E : ”1.0074V”

Measured value of the input (V1) shown on Display B
AC measurement is performed (RMS value).

• Display F : ”-01.302%”

Indicates the gain correction data in percent (%).

 Gain calibration setting method
To execute the gain calibration, follow the procedure mentioned below:(1) Connect the AC standard voltage and current generator to the voltage and input
terminals as shown on page 8 - 10.
(2) Select a range with the FUNCTION keys on Display C. The initial value is present range
setting. Usually, the auto range may be set. If nothing has been input, the minimum
range is set.
(3) Select the input of which gain is to be calibrated. For this purpose, select the voltage
input or current input with the FUNCTION keys on Display B, and the element withcorrection data with

▲ ,+15.000%. At 00.000%, if the,▲(4) Change the gain correction data. Move the cursor with▲

ELEMENT keys.
keys, and change thekeys. The range of gain correction data is -15.000% to▼▼

key is pressed, a minus sign is displayed.

(5) Successively, to execute the calibration of another input, switch the input with the
FUNCTION and ELEMENT keys on Display B and perform the operation in step (4).
(6) To execute the calibration of all ranges, switch the range with the FUNCTION keys on
Display C and repeat the operation in steps (3) to (5).
(7) When all the gain calibration finished, press the ENTER key to store the gain correction
data.

2721/2722

8-9

TROUBLESHOOTING AND MAINTENANCE

8.5 Performance Testing Checking before performance testing
Before the performance testing, check the following items:• Warm-up time

: 2 hour or more

• Ambient temperature/ humidity : 23±5°C / 20 to 80%RH (no-condensing)• Power voltage: 100V±2V

 Required instrument
For the performance testing, the following instrument is required:• AC standard voltage and current generator

1V to 640V, 40mA to 24A (11A) Performance testingz Connection with AC standard voltage and current generator
Connect the product and AC standard voltage and current generator as shown below:
CNTR

ELMT 1

ELMT 2

ELMT 3

Ｖ
±

Ｖ
±

Ｖ
±

A

A

A

±

±

±

ELMT 0

VoltageV

A

Current

Connect the voltage output of the generator to the “V, ±” terminals of ELEMENT 1, 2, 3, (0)and the current output to the “A, ±” terminals of ELEMENT 1, 2, 3, (0).
Connect the voltage in parallel, and the current in series.

z Checking voltage and current accuracy
Turn off the auto range setting (manual), and switch the range in the range setting mode,
and input full scale value in the set range. The accuracy is normal if the measured value is
within ±0.1%.
For the auto range setting, see “3.3 Setting Measurement Conditions” (p.3-15), and for therange switching, see “6.5 Range Display / Setting (RNG-SET)” (p.6-6).
z Checking phase difference accuracy
Since the same signal is input for the phase measurement, the accuracy is normal if a phasedifference between voltages is within ±0.05 deg, or a phase difference between currents iswithin ±0.1 deg.

8 - 102721/2722

9. SPECIFICATIONS Electrical ratingz Voltage input block• Input format

Floating input (resistance potential dividing type)• Number of inputs

3 phases + 1 phase (option: 2725 Input unit)• Input terminal format

Binding post

• Measurement range

20% to 110% of each input range
However, maximum measurement voltage 650Vrms (±920V)• Max. allowable input

Continuous: ±920V or 650Vrms whichever small• Input range

1V, 2.5V, 5V, 10V, 20V, 40V, 80V, 160V, 320V, 640V

• Input impedance

About 1MΩ (full range)• Withstand voltage

AC2kV, one minute/±920V, continuous(between voltage input terminal and case, between voltage andcurrent input terminals)z Current input section• Input format

Floating input(Shunt input system) or external voltage probe input• Number of inputs

3 phases + 1 phase (option: 2725 Input unit)• Input terminal format (the following two inputs are changed over by panel switch)
Shunt input:
Large type binding post
External input:
Current probe input connector RM515EPA-10PC : HIROSE• Measurement range
Shunt input
External input• Max. allowable input
Shunt input:
External input:

date 2010/6/14(#5)• Input range
Shunt input:
External input:• Input impedance
Shunt input:
External input:• Withstand voltage

2721/2722

20% to 110% of each input range
However, maximum measurement current 25Vrms (35Apeak)±2V F.S
Instantaneous (1 sec): ±60A or less / Continuous: ±35A or 25Arms
whichever smaller
Maximum ±10V or less
0.04A, 0.1A, 0.2A, 0.4A, 0.8A, 1.6A, 3.2A, 6.4A, 12A, 24A
2A, 5A, 10A, 20A when 20A clamp is used
20A, 50A, 100A, 200A when 200A clamp is used
1mA, 2.5mA, 5mA, 10mA when “2726 Micro-current probe” is used
About 5mΩ (full range)
About 30kΩ (full range)
AC2kV, one minute/±920V, continuous(between current input terminal and case, between voltage andcurrent input terminals)

9-1

SPECIFICATIONS• Connectable external current probe
2726 Micro-current probe (option)
Rated current: 10mA
Measurement range : 200µA to 11mA
Amplitude accuracy : ±(0.1% of rdg +0.1% of range) (40 to 100Hz)
Phase accuracy: ±0.2deg(40 to 100Hz)

z Voltage measurement accuracy *• 40Hz to 100Hz±(0.05% of rdg + 0.05% of range)• 10Hz to 40Hz,100Hz to 1kHz±(0.1% of rdg + 0.1% of range)• DC±(0.5% of rdg + 0.5% of range)z Current measurement accuracy *• 40Hz to 100Hz±(0.05% of rdg + 0.05% of range + 40µA)• 10Hz to 40Hz,100Hz to 1kHz±(0.1% of rdg + 0.1% of range + 40µA)• DC±(0.5% of rdg + 0.5% of range + 40µA)• 40Hz to 100Hz (External current probe input)±(0.05% of rdg + 0.05% of range)(Error in probe not included)z Phase measurement accuracy *• 40Hz to 100Hz• 10Hz to 40Hz,100Hz~1kHz±0.05deg (voltage-to-voltage phase difference)±0.1deg (voltage-to-current, current-to-current phase difference)±0.2degz Active power measurement accuracy *• 40Hz to 100Hz±(0.1% of rdg + 0.1% of range + ∆F% of rdg)

• 10Hz to 40Hz,100Hz to 1kHz±(0.2% of rdg + 0.2% of range + ∆F% of rdg)
• DC±(1% of rdg + 1% of range)

The error increase amount ∆F (%) due to power factor is obtained by the following expression.

∆F=∆φ × 2π× tan(φ) × 100(%)
360

φ is measurement phase difference (deg), and ∆φ is phase error (deg) in this device.
Power range = Voltage range × Current range*: Standard condition
20 to 100% input of range, ambient temperature 23±5°C, supply voltage 100V±2%, input waveform: sine
wave, average wavenumber 16, current input: internal shunt, after offset calibration after heat run

9-2

2721/2722

SPECIFICATIONS*: Distorted wave measurement accuracy
When the voltage and current are distorted waves, the measurement accuracy of voltage, current, power,
and phase is same, provided that the following conditions are satisfied.
z Harmonic 10-order or lessz Harmonic frequency 20kHz or lessz Harmonic content rate 40% or lessz Impedance measurement• Function

Calculation result by the following expression of each phase can bedisplayed

Z1 =Vn, Z2 =InVn
3 × In, Z3 =Vn
2 × I n × sin φVVoltage value,
In : Current
value, φ : Phase difference
Vnn:：電圧値, I n ：電流値
, φ：位相差• Phase selection

Select with element keys on Display D

z Frequency measurement• Measurement range

10Hz to 20kHz• Display digits

5 digits (10.000 to 20.000k)• Measurement input

Input set as SYNC signal(SYNC signal is V1, V2, V3, V0, A1, A2, A3, A0, LINE)• Accuracy±(0.05% of rdg + 1digit)z Counter function• Measurement mode

Single interval mode (Single-operation time difference measurement)
Dual interval mode (Dual-operation time difference measurement)
Multi interval mode(Dual-operation time difference measurement,
max. & min. values hold)One shot mode (Pulse width measurement)
Train mode (Pulse width integration measurement)• Start input (counter start signal)
Input format
Voltage input or contact input, floatingWithstand voltage: AC500V, one minute/±85V continuous
Input terminal format: Binding post
Voltage input
Voltage input range: ±200V
Threshold value voltage: 2.5V
Input impedance : about 200kΩ
Contact input
Open circuit voltage: About 12V
Short-circuit current: 15mA or less
Output impedance: about 1kΩ
Input format switching
By front panel key
Operation mode switching By front panel key
Make Î Break / Break Î Make
Make: 0V at voltage input, Short at contact input
Break: 2.5V or more voltage at voltage input, Open at contact input
MonitorInput state is displayed on the front panel

2721/2722

9-3

SPECIFICATIONS• Trip input (Counter stop signal)
Input format
Voltage input or contact input, floatingWithstand voltage: AC500V, one minute/±85V continuous
Input terminal format
Binding post
Voltage input
Voltage input range: ±200V
Threshold value voltage: 3 ranges of (1) about ±2.5V, (2) about ±8V,(3) about ±50V
Input impedance : about 200kΩ
Contact input
Open circuit voltage: about 12V
Short-circuit current: 15mA or less
Output impedance : about 1kΩ
Input format switching
By front panel key
Operation mode switching By front panel key
Make Î Break / Break Î Make
Make: 0V at voltage input, Short at contact input
Break: Threshold value or more voltage at voltage input, Open at
contact input
MonitorInput state is displayed on the front panel• Reset input (counter reset signal)
Input format
TTL input (DC voltage, decision voltage about 2.5V), either sideconnected to the case
Input terminal format• Chattering time

Binding post
1 to 100ms 1ms resolution• Time measurement accuracy ±(0.1% of rdg + 1digit)±(0.1% of rdg + 1digit) + 1ms when the chattering eliminating
function works• Time measurement range (resolution)
0.1ms to 1677s (auto range)
0.1m to 999.9ms (0.1ms)
1.0000 to 9.9999s (0.0001s)
10.000 to 99.999 (0.001s)
100.00 to 999.99 (0.01s)
1000.0 to 1677.0 (0.1s)

z Integration function• Measurement item
• Measurement mode
Manual integrate mode
Time integrate mode
Real time integrate mode

Active power integration, reactive power integration, current integration

Integration starts with START key and stops with STOP key
Integrated value is reset with RESET key
Integration starts with START key and stops after the time set totimer elapsed.
Maximum integrated time: 999H59M (resolution: 1 minute)Integration starts at reserved start time and stops at stop time.

• Display update cycle

About 1 sec (average function is turned off at integrating operation)• Measurement range(resolution)

00.001mWh to 99.999mWh
100.00mWh to 999.99mWh
1.0000Wh to 9.9999Wh
10.000Wh to 99.999Wh
100.00Wh to 999.99Wh
1.0000kWh to 9.9999kWh
10.000kWh to 99.999kWh
100.00kWh to 999.99kWh
1.0000MWh to 9.9999MWh

9-4(0.001m)(0.01m)(0.0001)(0.001)(0.01)(0.0001k)(0.001k)(0.01k)(0.0001M)

2721/2722

SPECIFICATIONSz Scaling function• Setting range

0.001m to 999.9k (m = 10-3, k = 103)z Average function• Averaging countMoving average: 1, 2, 4, 8, 16, 32, 64 times
Wavenumber average: 1, 2, 4, 8, 16, 32 timesz Sampling (display update cycle)• Cycle0.2 to 1s(variable depending on averaging count or setting of
measurement items)z Remote control function• Communication system

GPIB or RS-232C (cannot be used at the same time)• Setting items

Items settable with operation panel can all be set• Data reading items

24 data can be read at a time
Communication data and display data can be set separately

 Environmental conditions• Temperature andhumidity range

Performance guaranteed: 0 to 40°C / 20 to 80%RH
Note: 23±5°C for some items
Storage: -10 to 50°C (no-condensing)• Warm-up timeabout 30 mini.

 Power supply• Power supply

Voltage range
Frequency range
Power consumption• Withstand voltage

AC100V / 120V / 220V / 240V±10%(250V or less)48 to 62Hz
About 53VA (main unit only)
About 62VA (with 2725 input unit)

AC1.5kV, one minute (case and input terminals together to power
supply input)

 Mechanical rating• External dimensions

Portable type:430(W) × 176(H) × 450(D) (mm)Rack mount type:434(W) × 177(H) × 500(D) (mm)(not including prongs and front panel cover)• Weight

2721: About 16kg (main unit only), about 17kg (with 2725)(not including front panel cover)2722: About 16kg (main unit only), about 17kg (with 2725)

2721/2722

9-5

SPECIFICATIONS

 2721 External dimensions (Portable type)[Optional when placing an order]
2725 Input Unit

Surface treatment
Front panel: 5Y8.5/1 Semi-matte, Plastic sheet

Top cover: Coating 5Y6.5/1 Emboss

Side covers: Coating 5Y6.5/1 Emboss

Bottom cover : Coating 5Y6.5/1 Emboss

9-6

2721/2722

SPECIFICATIONS

 2722 External dimensions (Rack mount type)

Front view

Side view

Surface treatment
Front panel: 5Y8.5/1 Semi-matte, Plastic sheet

Rear panel: Coating 5Y6.5/1 Semi-matte

Top cover: Vinyl chloride decorated steel sheet 5Y6.5/1 Emboss

Side covers: Vinyl chloride decorated steel sheet 5Y6.5/1 Emboss

Bottom cover : Vinyl chloride decorated steel sheet 5Y6.5/1 Emboss

Rear view[Optional when placing an order]
2725 Input Unit

 2726 Micro-current probe /External dimensions

Surface treatment

Cable length 1M

Panel: Munsell 5Y8.5/1 Plastic sheet
Case: Munsell 5Y8.5/1 Leather tone

2721/2722

9-7

SPECIFICATIONS

MEMO

9-8

2721/2722

────── WARRANTY ──────
NF CORPORATION certifies that this instrument was thoroughly tested and inspected andfound to meet its published specifications when it was shipped from our factory.

All NF products are warranted against defects in materials and workmanship for a period of
one year from the date of shipment. During the warranty period of, NF will, at its option,either will repair the defective product without any charge for the parts and labor, or either
repair or replace products which prove to be defective. For repair service under warranty,
the product must be returned to a service center designated by NF. Purchaser shall prepay
all shipping cost, duties, and taxes for the product to NF from another country, and NF shall
pay shipping charge to return the product to purchaser.
This warranty shall not apply to any defect, failure or damage caused by improper use,
improper or inadequate maintenance and care or modified by purchaser or personnel otherthan NF representatives.

NF CORPORATION

2721/2722 Instruction Manual
NF Corporation
6-3-20 Tsunashima Higashi, Kohoku-ku, Yokohama
223-8508, JAPAN
Phone: +81-45-545-8128

Fax: +81-45-545-8187

Copyright 1996-2010, NF CORPORATION

http://www.nfcorp.co.jp/

NF Corporation
6-3-20 Tsunashima Higashi, Kohoku-ku, Yokohama 223-8508 JAPAN