AD-8551R

Modbus RTU Convertor

1WMPD4003931C

This manual and Marks

All safety messages are identified by the following, “WARNING” or“CAUTION”, of ANSI Z535.4 (American National Standard Institute: Product
Safety Signs and Labels). The meanings are as follows:
WARNINGA potentially hazardous situation which, if not avoided,
could result in death or serious injury.

CAUTION

A potentially hazardous situation which, if not avoided,
may result in minor or moderate injury.

This is a hazard alert mark.
This manual is subject to change without notice, at any time, to improve theproduct.
The contents of the product specifications and this manual are subject tochange without any obligation on the part of the manufacturer.
Under the copyright laws, the software (program) described in this manual iscopyrighted, with all rights reserved.
The software may be installed into one computer and may not be installed
into other computers without the prior written consent of A&D Company,
Limited. Copying includes translation into another language, reproduction,
conversion, photocopy and offer or loan to another person.

2019 A&D Company, Limited. All rights reserved.
No part of this publication may be reproduced, transmitted, transcribed, ortranslated into any language in any form by any means without the written
permission of A&D Company, Limited.

Contents
1. Introduction .........................................................................................................................................................4
Features .......................................................................................................................................................4
Cautions .......................................................................................................................................................5
2. Composition and Names ....................................................................................................................................6
AD-8551R .....................................................................................................................................................6
Accessories ..................................................................................................................................................6
3. Specifications .....................................................................................................................................................7
Dimensions ...................................................................................................................................................7
Applicable models .........................................................................................................................................8
4. Power Terminal ...................................................................................................................................................9Power-supply voltage ...................................................................................................................................9
Connecting example ...................................................................................................................................10
Internal connection status ...........................................................................................................................10
5. RS-485 Interface .............................................................................................................................................. 11
RS-485 specifications ................................................................................................................................. 11
Connections ................................................................................................................................................12
6. RS-232C Interface ............................................................................................................................................13
RS-232C specifications ..............................................................................................................................13
Connecting cable ........................................................................................................................................13
7. Switch ...............................................................................................................................................................14
How to operate the switch ..........................................................................................................................14
Factory setting ............................................................................................................................................14
RS-485 function settings .............................................................................................................................15
RS-232C function settings ..........................................................................................................................17
Fixed decimal point function .......................................................................................................................18
8. LED (status, error display) ................................................................................................................................19
9. Communicaiton in Modbus RTU Mode .............................................................................................................20
Preparing for communication ......................................................................................................................21
Data address ..............................................................................................................................................22
Detailed information on Holding Register 1 ................................................................................................23
Detailed information on Holding Register 2 (only forAD-4212C/AD-4212D).......................................................................24
Communication format ................................................................................................................................25
Operating example (When connected to the AD-4212C/AD-4212D) ..........................................................27
10. Communication in Command Mode ...............................................................................................................29
Preparing for communication ....................................................................................................................29
Communication format ..............................................................................................................................30
11. Troubleshooting ..............................................................................................................................................32
Modbus RTU mode communication check ................................................................................................32
Command mode communication check ....................................................................................................33

3

1. Introduction
Thank you for purchasing the AD-8551R Modbus RTU convertor.
Please read this manual completely before using the AD-8551R.

Features
The AD-8551R converts the RS-232C communications of the weighing device into RS-485 (Modbus RTU)
communications (RS-232C/RS-485 converter). Use of the RS-485 enables the collection of data control of up to 31
weighing devices (addresses ranging from 1 to 63) by a single PLC.
■The RS-485 communication method of the AD-8551R can be used by selecting either Modbus RTU communication(Modbus RTU mode) or ASCII code command communication (command mode).
■The measurement value can be reset to zero (re-zero) by operation from the PLC or PC.
■When connected to an AD-4212C and AD-4212D, etc., it is possible to change the response speed, perform calibration
with an external weight, and supply power from the weighing device.
■The hooks on the back of the AD-8551R allow one-touch mounting on a DIN rail.

Host

RS-485
communication(PLC, PC, etc.)

RS-232C
communication

AD-8551R

RS-232C
communication

AD-8551R

・
・
・

・
・
・

RS-232C
communication

AD-8551R

Weighing device
AD-4212C, etc.
Weighing device

・・・
Weighing device

4Cautions
Before use, confirm the following articles for safe operation.

Grounding The Convertor

Be sure to ground this convertor. (For the internal connection status of AD-8551R, refer to “4-3 Internal
connection status”.
Separate this earth ground line from others, like ground line of a motor, inverter or a power source. Unless theconvertor is grounded, it may result in receiving an electric shock, cause operation error or catch fire.

Proper Power Source And Power Cable

Confirm the AC voltage, frequency and power tolerance of the power cable (refer to “4. Power Terminal”). If thevoltage range of the cable is lower than the power line voltage, it may cause leakage or catching fire. Use pole
compression terminals to connect the power cable to the terminals.

Splashing Water

The module is not water-resistant type.

Flammable Gas

Do not install the convertor where flammable gas is present.

Heat Radiation Of The Module

Space out instruments to radiate heat sufficiently.
Do not use in an environment where the ambient temperature exceeds the operating temperature range [-10℃ to+50℃, 85% RH or less (no condensation)].
This unit is covered with a transparent plastic protective cover at the time of shipment.
After installing and connecting, be sure to remove the protective cover before turning on the power.
If it is used without removing the protective cover, this unit will overheat.
The protective cover is for preventing the entry of wire scraps and the like during installation and connecting.
Do not remove it until installation and connecting are complete.

This unit

Protective cover①②Remove the two tabs on the lower
surface of the protective cover andremove the protective cover.

Protective coverThis unit
This unit with a protective cover

How to remove the protective cover52. Composition and Names
AD-8551R
Rear panel side
DIN rail hook

Front panel side
LED (Status display part)

DIN rail groove
Vent hole
RS-485 connector

SwitchVent hole

RS-232C connector

Pull down when removingfrom DIN rail
DC power connector

DIN rail mounting example

DIN rail groove

DIN rail (width 35mm)

Accessories■Simplified instruction manual■RS-485 connector (power clamp wire mount socket)
Model : AX-35505-6200-A (Made by 3M 35505-6200-A00 GF)

6

3. Specifications
Voltage requirement:12 to 24 VDC [+ 10%, -15%]
Power requirement:2W Max
Communication interface :RS-485 (Modbus RTU or command for connection to control equipment)
Refer to “5-1 RS-485 specifications”:RS-232C interface (For connection to weighing device)
Refer to “6-1 RS-232C specifications”
Communication connector: 5 pin (male): Made by 3M 35605-5153-A00 (For RS-485 interface)
D-Sub 9 pin (male) (For RS-232C interface)
Operating condition:-10℃ to + 50℃, Max 85% RH (no condensation)
External dimensions:35 (W) x 110 (H) x 101 (D)Mass:Approximately 170g
Accessory:RS-485 connector (power clamp wire mount socket) 1 piece

Dimensions

Unit：mm7

Applicable models■Functions available for each model, accessories needed for connection to AD8551R.
Accessories needed to connect the AD8551R
to a weighing device

AD4212C⋆4

AD4212D

Connector for
A&D’s external
display
Connector for the
PC / PLC ⋆4

Data that can be read from the hostCable needed forconnection between
weighing device andAD8551R

Unnecessary

Cable included with theweighing device

○

○

○

○

○

Cable included with the

○

○

○

○

○

Unnecessary
Unnecessary

weighing device

Weighing
StatusResponse
Calibration status
information
speed
value

GF, GF-K

Unnecessary

AX-KO1710-200

BM, GH

Unnecessary

AX-KO2741-180

HR-i

Unnecessary

AX-KO2741-180

GR

Unnecessary

AX-KO1710-200

○
○
○
○
○
○
○
○
○
○
○
○

HR

(Included with

AX-KO1710-200○

Unnecessary

AX-KO1710-200

BA-T

Unnecessary

AX-KO2741-180

BA

Unnecessary

AX-KO2741-180

GX-A / GX-M

Unnecessary

AX-KO2741-180

GF-A / GF-M

Unnecessary

AX-KO2741-180

FZi, HR-AZ

Unnecessary

AX-KO2741-180

FXi, HR-A

Unnecessary

AX-KO2741-180

GX, GX-K, GP

Unnecessary

AX-KO1710-200

weighing device)
FC-i

Unnecessary

AX-KO2741-180

HC-i

HC-03i

AX-KO1786-200

EKi, EKi

Unnecessary

AX-KO2741-180

EJ, EJ-B

EJ-03

AX-KO2741-180

EK-L

Unnecessary

AX-KO2741-180

HV-CWP

HVW-03CWP

AX-KO3285-320

HV-C, HV-CP, HW-C, HW-CP

HVW-03C

AX-KO2741-180

HV-GV, HW-GV, HV-WP, HW-WP

Unnecessary

AX-KO1786-200

HV-GL / HW-GL

Unnecessary

AX-KO1786-200

FG

FG-23 / FG-24

AX-KO1786-200

FS-i

FS-03i

AX-KO3285-320

SC / SE

SCE-03

AX-KO3285-320

SW

SW-03

AX-KO3285-320

FG-CWP

Unable to connect

Unable to connect

Unnecessary

Changing
the unit

○*3

Zero

TaringCalibration withinternal weight

○

×

×

×

○

○

○

×

○

×

×

○

○

○

○

×

Calibration weight
Re-zerovalue

Calibration with yourown weight

Changing Changing thethe display
response
digit
speed

○
○
○
○
○
○
○
○
○
×

×
×
×
×
×
×
×
×
×
×
×
×

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○
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○
○
○
○
○

AX-KO4472-1000

AD4212A/B

GC

Convenient functions
Commandmode⋆1

Operations that can be made from the host

Weighing device
output options

HR-03

⋆1.

Modbus RTU

AX-KO2741-180

○
○
○
○
○
○
○
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×

○

⋆5
⋆5
⋆5
⋆5
⋆5
⋆5
⋆5
⋆5
⋆5
⋆5
⋆5
⋆5
⋆5
⋆6
⋆6
⋆5

⋆5 ⋆7
⋆5
⋆6
⋆6
⋆6
⋆6
⋆6
⋆6
⋆6
⋆6

×

⋆6

×
×
×
×
×
×
×
×
×
×
×
×

×
×
×
×
×
×
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×

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×

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×

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×

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×
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×
×

○
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×
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×
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×

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×
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×
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×

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×
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×

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×

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×
×
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×
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×

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×
×
×
×
×
×
×

×
×
×
×
×
×
×

○
○
○
○

×
×

Auto power onfunction⋆2

×
×
×
×
×
×
×
×
×
×
×
×

○
○
○
○

×

Power supply
from theweighing
device

○
○
○
○
○
○
○
×

○
×

○
×
×

×

○
○
○
○
○
○

*8

×
×
×
×
×
×
×
×
×

When transferring a large amount of data from a weighing device all at once (GLP output, batch output of data memory, etc.), data may be lost.
If the weighing device does not have an auto power-on function or auto-start function, it is necessary to turn on the display or each weighing device by key operation after turning on the power.
⋆3. When using the AD4212C in command mode, it is necessary to change to internal settings in advance to enter key mode.
Also, control characters beginning with “@” output from the AD4212C are not output from the AD8551R to the RS-485 side.
⋆4. The AD4212 has two types of RS-232C connectors. When using in Modbus RTU mode, connect the connector for A&D’s external display, and when using in command mode, connect the connector for PC/PLC and RS-232C connector of theAD8551R.
⋆5. Some functions (calibration error flag) cannot be used.
⋆6. Some functions (re-zero flag and calibration error flag) cannot be used.
⋆7. The EJ120B / EJ200B / EJ300B / EJ410B / EJ610B / EJ1500B / EJ2000B / EJ3000B / EJ4100B / EJ6100B cannot use the re-zero flag.
⋆8. Power can be supplied from the weighing device when the adapter is connected to the weighing device.
⋆9. Although a weighing device does not have an auto power-on function or an auto start function, it automatically shifts to the weighing display after the power is turned on, so no key operation is required.
⋆2.

8

○
○
○⋆9
×
×
×
×
×

○
○

4. Power Terminal
When connected to a specific weighing device such as the AD-4212C / AD-4212D, power can be supplied from theweighing device (RS-232C connector). No power connecting is required (Refer to “3-2 Applicable models”, “6. RS232C Interface”).

Power-supply voltage
Connect a constant voltage of external power supply (+ 10% -15%) within the range of 12 to 24 VDC to the DC power input
terminal.

Caution●Do not use at a voltage exceeding the rated voltage range (12 to 24 VDC +10%-15%)･Doing so may cause failure or heat generation.
･This unit may not operate normally.
●Ground the FG terminal of the switching power supply used for the power supply of this unit.
●The power line of this unit should be dedicated for this unit, and be separate from other drive devices.
･If strong noise is generated from the power line of another device, this unit may be damaged.
･This unit may not start normally due to the inrush current of other drive devices.
･Depending on the circuit configuration of this unit, other drive devices may not operate normally.
●Select a switching power supply capacity of approximately 2W per unit for the dedicated power supply line for thisunit.
･If the power capacity is insufficient, this unit may not operate normally.

■Connector:DC power input terminal
DC+
0V
FG

Signal name
DC+
0V
FG

Description
Power supply 12 to 24V input
Power supply 0V input
Frame ground9Connecting example
To insert or remove the wire, press the button part of the connector with a screwdriver or the like.
Modifying the tip of the wire with a bar-type crimp terminal or the like recommended.
Button part to push when inserting andremoving.

Power wire

Bar crimp terminal

Connection conductor specifications
Clamping range (rating)
AWG
Solder plated wire
Applicable wire Stranded wire
Bar crimp terminal DIN 46228 Part 1
Bar crimp terminal (With color)
DIN 46228 Part 4
Length0.20 mm2 to 1.5 mm2
AWG24 to AWG16
0.2 mm2 to 1.5 mm2
0.2 mm2 to 1.5 mm20.25 mm2 to 1.5 mm20.25 mm2 to 0.75 mm2
8 mmInternal connection status
AD-8551R
RS-485SLD(5)

Spring pin

RS-232C
Din rail connection
Shell
DC power input terminal
Approx. 820kΩ
0V(2)
FG(1)

10

5. RS-485 Interface
RS-485 specifications■Connector (Made by 3M

５
４
３
２
１

⋆1.

35605-5153-A00)

Pin No.
54
3
2
1

SignalSLD
SG
DATADATA+

Direction
Input/Output
Input/Output

Description
Shield ⋆1
N.C
Signal ground
Send / Receive data
Send / Receive data

Connect the shield of the RS-485 cable.
The shield terminal is connected to the DC power input terminal FG, RS-232C connector shell, and DIN rail
connection spring connector.
(Refer to “4-3 Internal connection status”)■Communication specifications
Communication method [SW-2 No.3]

Item
Baud rate
Data bit
ParityStop bit
Terminator

Modbus RTU mode

[SW-1 No.1, 2]

Command mode

9600*, 19200, 38400, 115200bps⋆7bit or 8 bit
EVEN*, ODD, NONE
1 bit (fixed)
A silent interval of at<CR><LF> (fixed)
least 3.5 character
times
Built-in:Yes(100Ω)/ No * selected by switch
01* to 63
Modbus RTU*
ASCII code commands[SW-1 No.3, 4]

Terminating resister[SW-5 No.1]
Device address setting [SW-3 No.3, 4, SW-4]
Code*Factory setting⋆Changing the data bit is a function that was added later due to the specification change. It canbe used when there is a description on SW-2 No. 4 on the main body label. In Modbus RTU
mode, it is fixed at 8 bits.

11

Connections■How to connect③ Branching connector① RS-485 connector (power clamp wire mount socket)② RS-485 cable

Single connection
Item

Multi drop connection
Description

Accessory① RS-485 connector
Model: AX-35505-6200-A○(power clamp wire mount socket) (Made by 3M 35505-6200-A00)(1 piece)
Recommended specification･Twisted pair cable with shield② RS-485 cable
×･Wire conductor size AWG#20(0.50mm2)･Characteristic impedance 100ΩModel: AX-35715-A (Made by 3M 35715-L010-A00)*For multi drop connection.
③ Branching connector
×
RS-485 connector (power clamp wire mount socket) also needs tobe purchased additionally.

Before cable crimping■Connecting method of cable and connector
1. Connect the two signal lines (DATA+, DATA-) in twisted pairs
and wire the shield of RS-485 to the SLD terminal.
If the host device does not have a signal ground, the SG terminal
connecting is not necessary.

Body (black part)

Cover (yellow part)

2. Insert the lead wire all the way in to the cover (yellow portion) without
peeling off the cover of the lead wire.
3. Push the cover into the body and fix it.

4. Make sure that the cover is level with the body and that there is no gap
between the body and the cover.

After cable crimping
12

6. RS-232C Interface
RS-232C specifications■Connector(D-Sub 9 pin, male)
Pin No.
1
2
3
4
5
6
7
8
9
Shell

Shell

6
7
8
9

1
2
3
4
5

Inch screw

Signal
(Vs)
RXD
TXD
SG
(Va)
-

Direction
Input
Input
OutputInput-

Description
Input of power supply 0V ⋆1
Received data
Transmission data
N.C.
Signal ground
N.C.
N.C.
N.C.
Input of power supply 12V ⋆1
Shield⋆1.When connected to a specific weighing device such as the AD-4212C / AD-4212D, the AD-8551R can be operated
by supplying power from the weighing device. (RS-232C connector). (Refer to “3-2 Applicable models”).
■Communication specifications
Item[SW-1 No.1, 2]

Baud rate
Data bit
ParityStop bit
Terminator
Code

Setting
2400*, 4800, 9600, 19200bps
7 bit (fixed)
EVEN (fixed)
1 bit (fixed)<CR><LF> (fixed)
ASCII*Factory setting

Connecting cable
Connect with a cable applicable to the individual weighing device. Refer to “3-2 Applicable models”■Connection diagram(When connected to a weighing device.)
Weighing
device（DCE）

AD-8551R（DTE）

RXD ⋆１TXD ⋆１
SG(Vs)⋆2(Va)⋆2
FG

Shield

2

RXD

3

TXD

5

SG

1

(Vs)

9

(Va)
FG

⋆1.Depending on the weighing device, RXD and TXD may be shown on the opposite side (weighing device output:
TXD, weighing device input: RXD)
⋆2.May vary depending on the weighing device.

13

7. Switch･Set the parameters required for communication using the AD-8551R switches (SW-1 to 5).
Caution･If the setting is changed, be sure to turn on the power off and on again of AD-8551R.
When the power is turned on, the switch status is read and applied to operations

How to operate the switch
SW-1 to 3, 5
When lever No.1 is moved to the “ON” side, “1” Is set.

“1”

Lever

“0”
No. 1 on the left and No. 4 on the right.
SW-4

Turn the center arrow to set.
It can be set from 0 to F.

Factory setting
The switch status and settings at the factory setting are as follows. Refer to “7-3 RS-485 function settings” “7-4
RS-232C function settings” for the settings that need to be changed.

0

0 0
SW-1

0

0

0

0

SW-2

Item
RS-485 baud rate
RS-485 parity
RS-232C baud rate
RS-485 communication method
RS-485 data bit
Device address
Terminating resistor
Fixed decimal point function

0

0

0 0

1

1

0

SW-3

Factory setting
value
9600
EVEN
2400
Mosbus RTU mode
8 bit
01
None
AUTO

14

1

1

0
SW-4

SW-5

Switch status at factory setting
SW-1 No1:0
SW-1 No3:0
SW-2 No1:0
SW-2 No3:0
SW-2 No4:0
SW-3 No3:0
SW-5 No1:0
SW-5 No2:1

SW-1 No2:0
SW-1 No4:0
SW-2 No2:0
SW-3 No4:0

SW-4 :1

SW-5 No3:1

SW-5 No4:1

RS-485 function settings■Communication settings
SW-1
Baud rate : RS-485 Baud Rate

Setting status

Setting status

Parity:RS-485 Parity

9600 bps

EVEN

19200 bps

ODD

38400 bps

Setting prohibited

115200 bps

NONE

“1”
“0”
SW-1
■Settings for the RS-485 communication method
The RS-485 communication method of the AD-8551R can be selected from two types: communication using Modbus
RTU (Modbus RTU mode) and communication using ASCII code (command mode).
When set to command mode, the data bits can be selected from 7 bits and 8 bits.
(Changing the data bit is a function that was added later due to the specification change. It can be used when there
is a description on SW-2 No. 4 on the main body label. In Modbus RTU mode, it is fixed at 8 bits.)
SW-2
Mode:RS-485communication method

Setting status

Setting status

Modbus RTU mode

8 bit
7 bit

Command mode

(Only when set to command mode)

“1”
“0”

Data bitSW-2
15

■Device address allocation
Allocate a device address for each AD-8551R.
Device address allocation can be set from 01 to 63 using switches (SW-3, 4).
SW-2 No. 4, ADDRESS
Device Address
Setting prohibitedor no device setting *1
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63

Setting status
SW-3
SW-4
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F

SW-4

“1”
“0”
SW-3
*Do not set in Modbus RTU mode.
In command mode, the device address is not added.
The device address setting can be used as a simple RS232C and RS485 converter without individual
communication by address.
(Refer to “10-2 Communication format”)

16

■Terminating resistor selection
SW-5 No.1
Terminating Resistor

Setting status“1”

No terminating resistor

“0”
SW-5

With terminating resistor(Between [DATA+] and [DATA-] is 100Ω)

Example when several units are connected.

(ground)Connect termination resistors only at the ends of the network.

(ground)
Weighing
device.

Weighing
deviceSingle connection

Multi drop connection

RS-232C function settings■Communication setting
SW-2 No.1, No.2
Baud rate:RS-232C Baud Rate

Weighing
deviceSetting state

2400bsp

4800bps

9600bps

19200bps

“1”
“0”

SW-2
17

Weighing
deviceFixed decimal point function･The fixed decimal point function is valid only in Modbus RTU mode.
･ If the connected weighing device has a smart range function, the number of digits after the decimal point is
automatically changed.
If you want to fix the number of digits, use the fixed decimal point function.
Example of storage format with fixed decimal point function
Weighing device
output value

Setting of decimal
point position

123.456g

2
3
AUTO⋆1

123.45g2
3
AUTO⋆1AD8551R internal data
Decimal point
Weighing value
position(Holding Register:(Holding Register:
40 2001 to 2002)
40 2005 to 2006)
12345
2123456
3123456
3
12345
123450
12345

2
3
2

SW-5 No. 2 to No. 4
Setting of decimal point position:

Setting state

Decimal Point
0

1

2

3

4

“1”
5

“0”
SW-5

6

AUTO⋆1⋆1

Depending on the output of the weighing device, the number of digits stored in the weighing value(Holding Register: 40 2001 to 2002) and the decimal point position (Holding Register: 40 2005 to 2006) are automaticallyswitched.

18

8. LED (status, error display)
1

2

3

4

Place

Display

1

RUN

2
3

RXD
SD

4

RD

Color

StatusIlluminates when the AD-8551R is powered on.
Flashes when the RS-485 or RS-232C communication settings areBlue
incorrect.
(Refer to the following “RUN illumination status (Error display”)
Yellow Flashes when the AD-8551R receives data from the weighing device.
Green Flashes when the AD-8551R is transmitting data to the host.
Flashes when the AD-8551R is receiving data from the host (PLC, PC,
Orangeetc.)■RUN Flashes status (Error display)
RUN illumination status
Always illuminatedStatus
No communication error

Fast flashing(0.1 second period)

RS-485 communication error

Slow flashing(2 second period)

RS-232C communication error

Illumination timing at time of error
PeriodAt the time of RS-485 communication error: 0.1 seconds
At the time of RS-232C communication error: 2 seconds

IlluminatedOff
Caution･Communication errors can be detected as framing errors, parity errors, and overrun errors.
･If an error is detected in both RS-485 and RS-232C, RUN illumination status is fast flashing.
(Prioritize RS-485 communication errors)19

9. Communicaiton in Modbus RTU Mode･Weighing value reading and zero reset (re-zero) are possible.
･When using the following models, calibration (sensitivity adjustment) is possible via Mdbus RTU.
When calibrating with a weighing device rather than the ones listed below, use the key, etc. of the weighing device
while looking at the display of the weighing device.
Applicablemodel
AD-4212C
AD-4212D

Sensitivity
adjustment method
External weight ⋆1External weight ⋆1

Outline of procedure

While monitoring the balance status with the Holding Register, it isnecessary to instruct data acquisition by Coil and to load and unload theweight on the weighing instrument.
Built-in weight
After instruction by Coil, the holding register monitors until calibration iscompleted.
⋆1.When changing the weight value to be used, refer to the instruction manual of the individual weighing device.
■Notes on Modbus RTU communication with AD-8551R.
･The function codes and maximum number that can be supported by AD-8551R are as follows.
Code
Function name01
Read Coils
03
Read Holding Registers
05
Force Single Coil
15
Force Multiple Coils ⋆2⋆2.This is possible only when the number of Coils to be rewritten is one.
CautionRewriting of Holding Register is not supported.

20

Preparing for communication
1. Set the following setting items so that the RS-232C of the weighing instrument and AD-8551R are the same.
Reference: AD-4212C/AD-4212D factory setting
Setting item
Weighing device
AD-8551R
Baud rate
2400*, 4800, 9600, 19200 bps
Data bit
7 bit*
ParityEVEN*
Stop bit
1 bit*
Terminator<CR><LF>*
Data output format
A&D standard format*―
Data output mode
Settings for continuous―
output of weighing
values.(stream mode*)*AD-8551R factory setting (normally, the factory setting of AD-4212C / AD-4212D is the same.)
2. Set the following setting items so that the RS-485 of the host (PLC, PC, etc.) and AD-8551R are the same.
Setting item
Baud rate
Data bit
ParityStop bit
Terminator

Host(PLC, PC, etc.)
AD-8551R
9600*, 19200, 38400, 115200 bps
8 bit*EVEN*, ODD, NONE
1 bit*
No communication for 3.5 charavters*

Refer to ”4-2 Connecting example”, “5-2 Connections”, “6-2 Connecting cable” for connecting.
･Normally, when using the AD-4212C/AD-4212D, power can be supplied from the RS-232C terminal, so connecting
to the power terminal is not required.
・ When connecting to the AD-4212D in Modbus RTU mode, connect to the AD-8551R using the AD-4212D display connector.
4. Turn on the device power.
･Turn on the AD-8551R and the weighing device at the same time (within approximately 1 second) or turn on the
AD-8551R first. If the AD-8551R power is turned on late, the response characteristics (Holding Register: 40
2015-2016) may not operate correctly.
3.

21

Data address
CautionThe data address is described in the following two ways.
Absolute address:
The address where the data is stored.
Communication address: Start address for communication in Modbus RTU.
When communicating with Modbus RTU, the start address must be one less than
the address of the data to be read/written.
(For details of communication contents, refer to “9-5 Communication format”.)
Some communication software automatically sends one less than the address whencommunicating when an absolute address is specified.
■Coil address map
Absolute
address00

Data address (Coil)Communication address(decimal)

R/W

Item

Description

2001

0x07D0 (2000)“EXC” command output

2002

0x07D1 (2001)“CAL” command output

2003

0x07D2 (2002)“PRT” command output

2004

0x07D3 (2003)“R” command output

2005

0x07D4 (2004)

2006

0x07D5 (2005)“U” command output 2

2007

0x07D6 (2006)“RZ” command output

2008

0x07D7 (2007)“Z” command output

Performs zero reset (re-zero) of weighing
value

2009

0x07D8 (2008)“T” command output

Performs tare

R/W⋆1

Use for calibration (sensitivity
adjustment)
Performs zero reset (re-zero) of weighing
valueChanges the minimum display of theweighing device
Changes response characteristics orswitching units“SMP” command output⋆

When “1” is written, the AD-8551R outputs each command to the connected weighing device and returns
the Coil status to “0”. “0” is output when performing reading.
The operation differs depending on the weighing device. Refer to “3-2 Applicable models” or the operation
manual of the individual weighing device for the operation with that weighing device.

⋆1.
⋆2.

■Holding Register address map
Data address( Holding Register )Absolute
Communication address
address(Decimal number)

Description

0x07D0 (2000)

Weighing value (Lower)

2002

0x07D1 (2001)

Weighing value (Upper)

2003

0x07D2 (2002)

Status information (Lower)

2004

0x07D3 (2003)

Status information (Upper)⋆4

2005

0x07D4 (2004)

Decimal point position (Lower)

2006

0x07D5 (2005)
0x07D6~0x07DB(2006~20011)

Decimal point position (Upper)

2013

0x07DC (2012)2014

0x07DD (2013)

2015
2016

⋆3.
⋆4.
⋆5.

Item

2001

2007~2012
40

R/W

32 bit binary representation⋆4

32 bit binary representation
No function

R⋆3

Weighing unit (Lower)

0x07DE (2014)

Weighing unit (Upper)
Response characteristics(Lower)⋆5

0x07DF (2015)

Response characteristics

32 bit binary representation

32 bit binary representation⋆5(Upper)2017

0x07E0 (2016)2018

0x07E1 (2017)2019

0x07E2 (2018)2020

0x07E3 (2019)

Calibration status (Lower)⋆5
Calibration status (Upper)⋆5
Calibration weightvalue(Lower)⋆5
Calibration weightvalue(Upper)⋆5

It cannot be rewritten by writing from the master.
The function is limited if connected to other than AD-4212C/D.
Can be used only when connected to the AD-4212C/D.

22

32 bit binary representation

32 bit binary representation

Detailed information on Holding Register 1■Weighing value (Holding Register: 40 2001 to 2002), decimal point position (Holding Register :40 2005 to 2006)
Example of weighing value and decimal point position value by weighing device output.
(When the decimal point position by SW-5 is set to AUTO.)
Output value

123.456g

Data address(Holding Register)

Data

2001

0xE2402002

0x00012005

0x00032006

0x00002001

0x30392002

0x00002005

0x00022006

0x000040

123.45g

40

Description
Weighing value

0x0001E240 ⇒ 123456

Decimal point position
Weighing value

0x00000003 ⇒ 30x00003039 ⇒ 12345

Decimal point positon 0x00000002 ⇒ 2■Status information of weighing value (Holding Register: 40 2003 to 2004)
Data Address(Holding Register)Item2003.00

Stable / Unstable state of weighing value

2003.01

Weighing range over flag

Description
0: Unstable
1: Stable
1: When the weighing value exceeds the maximum display.
0: When the current weighing value is received from the weighing device.

2003.02

Non-weighing status flag

1: When the weighing value is interrupted for more than 2 seconds, re-zero or

2003.03

Re-zero flag

1: Processing re-zero⋆1

2003.05

Calibration in progress flag

2003.06

Calibration error flag⋆2

1: During calibration process⋆1
1: If the measured calibration weight value is not appropriate duringcalibration.
(It returns to “0” when the weighing mode is entered.)calibration is in progress.
40

2003.04

No function

2003.07 to 15

No function

2004.01 to 15⋆1.Flag does not change when operated with keys of the weighing device.
⋆2.Can be used only when connected to AD-4212C / D.
CautionBe sure to read “weighing value” and “weighing value status information” at the same time.
If they are read separately, depending on the update timing, the correspondence between the “weighing value” and“weighing value status information” may be different, so the status of the weighing value cannot be determined.

■Weighing unit (Holding Register: 40 2013 to 2014)
Relationship between stored value and unit
Value

Weighing unit
(mode)

Value

0x00000000

g (gram)

0x00000006

0x00000001

mg (milligram)

0x00000007

0x00000002

kg (kilogram)

0x00000008

0x00000003

PCS (pieces)0x00000009

0x00000004% (percent)

0x0000000A

0x00000005

ct (carat)

0x0000000B

Weighing unit
(mode)
mom(Momme)OZ(Ounce)Lb(Pound)OZt(Troy Ounce)dwt(Pennyuweight)
GN(Grain)23

Value
0x0000000C
0x0000000D
0x0000000E
0x0000000F
0x00000010

Weighing unit (mode)
TL(Tael)
Tol(Tola)MES(Messghal)N(Newton)
MLT(Programmable unit)

0xFFFFFFFF

Indistinguishable

Detailed information on Holding Register 2 (only for AD-4212C/AD-4212D)
The following items change only when connected to the the AD-4212C / AD-4212D.
When connected to another measuring instrument, they will be the initial values.
■Response characteristics (Holding Register: 40 2015 to 2016)
Value

Response characteristic status⋆10x00000000

Default value

0x00000001

FAST

0x00000002

MID

0x00000003

SLOW

0x00000004

User setting⋆2⋆1.FAST / MID / SLOW can be switched by writing “1” to Coil 00 2006.
⋆2.AD-4212C with fine response characteristics.
(Refer to WinCT-AD4212C additional instruction manual for setting method.)■Calibration status (Holding Register: 40 2017 to 2018)
Value

Response characteristic status

0x00000000

Default value

0x00000001

Waiting for zero point weighing

0x00000002

Weighing zero point

0x00000003

Waiting for weighing of calibration weight

0x00000004

Weighing calibration weight

0x00000005

Calibration completed

0x00000006

Calibration error■Calibration weight value (Holding Register: 40 2019 to 2020)
When executing calibration (sensitivity adjustment) with your own weight, the value of the calibration weight can bechecked.
‐The unit is gram and the decimal point is none.
‐Only when “Waiting weighing of calibration weight” is the value of the calibration weight to be used.
The initial value is “0xFFFFFFFF”. When returning to the weighing mode, it will return to the initial value.
Calibration weight value
to be used
100g

Data Address(Holding Register)

Data

2019

0x00642020

0x000040

24Description
Calibration weight value

0x00000064 ⇒ 100

Communication format
This is the format for communication between the AD-8551R and a host (PLC, PC, etc.) with Modbus RTU.
If communication between the host (PLC,PC, etc.) and AD-8551R is not possible, send the contents of the following
example from the host and check the communication.

■When writing to CoilOperation details
Write 1 to Coil 00 2004 of the AD-8551R where device address is 01 (Re-zero instruction to the weighing instrument).
Sent from the master
Field name

Device address

Example (Hexadecimal)None(No communication for 3.5 characters)
0x01

Function code

0x05

Start address(Upper)

0x07

Start address(Lower)

0xD3

Conversion data(Upper)

0xFF

Conversion data(Lower)

0x00

Error check

0x7CB7None(No communication for 3.5 characters)

HeaderTrailer

Description

0x07D3 = 2003
(Note that address for communication is 1 less.)

Response from the device
Field name

Device address

Example (Hexadecimal)None(No communication for 3.5 characters)
0x01

Function code

0x05

Start address(Upper)

0x07

0x07D3 = 2003

Start address(Lower)

0xD3(Note that address for communication)

Conversion data(Upper)

0xFF

Conversion data(Lower)

0x00

Error check

0x7CB7None(No communication for 3.5 characters)

HeaderTrailer

25

Description

■Holding Register read communication example
How to operate
Read 40 2001 to 2002 Holding Register of the AD-8551R where device address is 01 (Read the weighing value of the weighing
device).
Sent from the master
Field name

Device address

Example (Hexadecimal)None(No communication for 3.5 characters)
0x01

Function code

0x03

Start address(Upper)

0x07

Start address(Lower)

0xD0Conversion data (Upper)

0x00

Conversion data(Lower)

0x02

Error check

0xC486None(No communication for 3.5 characters)

HeaderTrailer

Description

0x07D0 = 2000
(Note that there are 40 0001fewer
addresses for communication)

Response from the device
Field name

Device address

Example (Hexadecimal)None(No communication for 3.5 characters)
0x01

Function code

0x03

Number of data bytes

0x04

Data 1(Upper)

0xD6

Weighing value:0x0012D687 =Data 1 (Lower)

0x87

1234567

Data 2(Upper)

0x00

Data 2 (Lower)

0x12

Error check

0xF25F

TrailerNone(No communication for 3.5 characters)

Header26

Description

Operating example (When connected to the AD-4212C/AD-4212D)
This is the procedure for basic operation of the weighing device in Modbus RTU communication.
■Reading weighing value
ProcedureContents

Modbus RTU access method

Coil address
AD-4212C

AD-4212D

Applicable Holding Register
address()data length1

Check decimal point position

Read the applicable Holding Register

40 2005-2006 (2word)2

Check unit

Read the applicable Holding Register

40 2013-2014 (2word)3

Check weighing value ⋆1

Read the applicable Holding Register4
5

40 2001-2002 (2word)
40 2003-2003 (1word)

Check the weighing value by
following steps 1 to 3.
Repeat steps 3 to 4. ⋆2

Status confirmation contents
Check decimal point positioneg) 0x00000003 → decimal point 3 digits
Check the applicable weighing unit from the valueeg) 0x00000000 → unit:gCheck the weighing valueeg) 0x00BC614E → 12345678
Check the status informationeg) 0x0001→ stable weighing valueeg) 12345.678 g (stable)⋆1. Be sure to read “weighing value” and “weighing value status information” at the same time.
If they are read separately, the weighing value status cannot be judged because the correspondence between the “weighing value” and “weighing
value status information” may differ depending on the update timing.
⋆2. If the decimal point position or unit is changed, or if the smart range function is used, perform step 1 and 2 as necessary.

■Re-zero (zero reset execution example)
ProcedureContents

Modbus RTU access method

Coil address
AD-4212C

AD-4212D

Applicable Holding Register
address() data length

Status confirmation contents

1

Instruct to start Re-zero

Set “1” to the applicable Coil

2

Confirm start of Re-zero

Read applicable Holding Register

40 2003 (1word)

Wait until “40 2003.03” becomes to ”1” ⋆3

3

Confirm during Re-zero

Read applicable Holding Register

40 2003 (1word)

Wait until “40 2003.03” becomes to “0”4

Confirm Re-zero completion

Read applicable Holding Register

40 2001-2002 (2word)

Confirm that it becomes “0x00000000” ⋆4

00 2004⋆3. Normally, changes immediately after setting “1” to Coil in the previous step.
When the weighing value is stable, re-zeroing is completed instantly and 40 2003.03 returns to "0", so the "1" state may not be read depending on the read timing.
⋆4. If weighing value is unstable, re-zero cannot be executed. Be sure to confirm completion of re-zero by confirming that the weighing value is“0x00000000”.
27

■Example of calibration (sensitivity adjustment) with external weight(Possible only with AD-4212C/AD-4212D)
ProcedureContents

Modbus RTU access method

1

Instruct start calibration mode

Set “1” to the applicable Coil

2

Confirm calibration mode

Read applicable Holding Register

Instruct to start weighing at zero

3

point

4

Confirm start weighing at zero point
Confirm that zero point is being

5

weighed.
Confirm the calibration weight value

6

to be used ⋆4

7

Coil address

Holding Register address

AD-4212C

AD-4212D

00 200200 2001() data lengh

Status confirmation contents

40 2017-2018 (2word)

Wait until “0x00000001” ⋆1

Read applicable Holding Register

40 2017-2018 (2word)

Wait until “0x00000002” ⋆1

Read applicable Holding Register

40 2017-2018 (2word)

Wait until “0x00000003” ⋆2Read applicable Holding Register

40 2019-2020 (2word)

00 2003

Set “1” to the applicable CoilPlace calibration weight
Instruct the start of weighing the

8calibration weight
Confirm weighing of calibration9

weightConfirm that calibration weight is

10

being weighed.

11

Remove calibration weight

12

Confirm transition to weighing status

00 2003

Set “1” to the applicable CoilRead applicable Holding Register

40 2017-2018 (2word)

Wait until “0x00000004” ⋆1

Read applicable Holding Register

40 2017-2018 (2word)

Wait until “0x00000005” ⋆2⋆3

Read applicable Holding Register

40 2017-2018 (2word)

Wait until “0x00000000”⋆1. Normally, changes immediately after setting “1” to Coil in the previous step.
⋆2. If the weighing device is unstable, sensitivity adjustment is not performed and it automatically shifts to weighing status (0x00000000).
⋆3. If the weighed calibration weight value is not appropriate, calibration error (0x00000006) will occur. After that, it automatically shifts to weighing status (0x00000000).
⋆4. If you want to change the value of the calibration weight to be used, confirm the instruction manual of the individual weighing device.
■Example of calibration (sensitivity adjustment) with built-in weight (Possible only with AD-4212D)
ProcedureContents

2

Instruct to start calibration withinternal weight
Confirm start of calibration

3

Confirm the end of calibration

1

Modbus RTU access method

Applicable Coil address
AD-4212C

Set “1” to the applicable CoilAD-4212D

Applicable Holding Register
address() data length

Status confirmation contents

00 2002

Read applicable Holding Register

40 2003 (1 word)

Read applicable Holding Register

40 2003 (1 word)
40 2017-2018 (2 word)

Wait until “40 2003.05” becomes “1” ⋆5
Wait until “40 2003.05” becomes ”0”
Confirms that “40 2017-2018”
becomes ”0x00000005” ⋆6⋆5. Normally, changes immediately after setting “1” to Coil in the previous step.
⋆6. If the weighing value is unstable, calibration completed (0x00000005) is not entered, and it switches automatically to weighing mode. Also, if the weighing value is not
appropriate, calibration error (0x00000006) will occur. After that, it automatically shifts to weighing status (0x00000000).
28

10. Communication in Command Mode
･Normally, one-to-many communication is enabled by adding a device address to the command communication when
performing one-to-one with the weighing device via RS-232C.
･The available commands are the same as the RS-232C commands for each weighing device. For details, refer to the
instruction manual of the individual weighing device.
CautionIf multiple data is output from the weighing device at one time (time and date are added to the weighing value, etc.),
data loss may occur.

Preparing for communication
1. Set the following setting items so that the RS-232C of the weighing device and AD-8551R are the same.
Reference: Factory setting of the AD-4212C/AD-4212D
Setting item
Weighing device
AD-8551R
Baud rate
2400*, 4800, 9600, 19200 bps
Data bit
7 bit*
ParityEVEN*
Stop bit
1 bit*
Terminator<CR><LF>*
Data output format
A&D standard format*―
Data output mode ⋆1､⋆2
Setting to output the―weighing value with an
external command.
(key mode,etc.)*Factory setting of the AD-8551R (normally, factory settings of AD-4212C/AD-4212D are same)⋆1. If each weighing device is set to automatically output data (auto print, interval mode, etc), multiple devices may
communicate simultaneously with RS-485 and may not communicate normally.
⋆2. With the AD-4212C, it is necessary to change the data output mode.
(Refer to the individual device instruction manual for how to change.)
2. Set the following setting items so that the RS-485 of the host (PLC, PC, etc.) and AD-8551R are the same.
Setting item
Host(PLC, PC.etc)
AD-8551R
Baud rate
9600*, 19200, 38400, 115200 bps
Data bit⋆7 bit or 8 bit*
ParityEVEN*, ODD, NONE
Stop bit
1 bit*
Terminator<CR><LF>*⋆Changing the data bit is a function that was added later due to the specification change. It can be used when
there is a description on SW-2 No. 4 on the main body label.
3. Refer to ”4-2 Connecting example”, ”5-2 Connections”, ”6-2 Connecting cable” for connecting.

･Normally, when using the AD-4212C, power can be supplied from the RS-232C terminal, so connecting to the power
terminal is not required.
･When connecting to the AD-4212D in command mode, connect to the AD-8551R using the AD-4212D PLC
connector.
4. Turn on the power for each device.

29

Communication format･Format sent from the host (PLC, PC, etc.).
Add “@**” (“**” is the device address 01 to 63 set with AD-8551R) before the command you want to send to theweighing device.
The AD-8551R with the matching device address outputs the command part excluding “@**” to the weighing device(RS-232C) side.
As an exception, when the device address 00 of the AD-8551R is set, all the data received by the AD-8551R is output
to the weighing instrument (RS-232C) regardless of whether the device addresses match or not.
･Format received by the host (PLC,PC,etc.).
A command with “@**” (“**” is the device address 01 to 63 set by AD-8551R) added before the data output from theweighing device is received.
As an exception, when the device address 00 of AD-8551R is set, the device address is not added and the data
output from the weighing instrument is received as it is.
* Control characters starting with "@" output from some measuring instruments such by the AD4212C are ignored by
AD-8551R and are not received by the PLC side.
■Example of obtaining weighing data from a weighing instrument connected to device address 01.
Host (PLC, PC, etc.)
@ 0

1

Q

CR

LF

@ 0

1

S

T

,

+

1

2

3

4

.

5

6

7

_

_

g

CR

LF

AD-8551R (device address 01)
Q

CR

LF

S

T

,

+

1

2

3

4

.

5

6

7

_

_

g

CR

LF

Weighing device

Timing of display rewriting of
the weighing device

Wait for display rewriting：After receiving the data request command,
the weighing device outputs the weighing value
at the timing of rewriting the display.

■Example of re-zeroing the weighing instrument connected to device address 01.
(In the case of weighing devices that support “R” commands)

Host (PLC, PC, etc.)
@

0

1

R

CR

LF

AD-8551R (device address 01)
R

CR

LF
Weighing device

CautionSome weighing devices do not respond to requests for weighing data during re-zero processing. Wait for the re-zeroprocess to finish and request the weighing data again. Also, available commands differ depending on the weighing
devices. For details, refer to the instruction manual of the individual weighing device.

30

■Example of obtaining weighing data from a weighing instrument connected to device address 00.
(When no address is added to the communication data.)

Host (PLC, PC, etc.)
Q CR

LF

S T

,

+ 1

2 3 4 .

5 6

7 __ g CR

LF

S T

,

+ 1

2 3 4 .

5 6

7 __ g CRLF

AD-8551R (device address 01)
Q CR

LF
Weighing device

Timing of display rewriting of
the weighing device

Wait for display rewriting：After receiving the data request command,
the weighing device outputs the weighing value
at the timing of rewriting the display.

■Example of control characters output from a weighing device connected to device address 01.
Host (PLC, PC, etc.)
@

0

1

S T

,

+ 1

R

CR

LF

+ 1

2

3

2 3 4 .

AD-8551R (device address 01)
@

S T

0

1
,

5 6

7 _ _ g CR LF

Control characters starting with "@" are not output tothe host side
4

.

5 6

Weighing device

31

7

_

_

g CR LF

11.Troubleshooting
Modbus RTU mode communication check
Phenomenon
RUN LED does not illuminate.

RXD LED does not flash.

RD LED does not flash.
RUN LED is flashing.
SD LED does not flash.

The data received by the host is
corrupted.
Non-weighing status flag is “1”.

AD-8551R settings cannot bechanged.

Confirmation and countermeasures
Confirm that the power supply is correctly supplied to the power supply terminalof the AD-8551R.
･Is the voltage appropriate? (12 to 24 VDC)
･Is the cable connected correctly?
Confirm that the weighing device is connected and set correctly.
･Is the cable properly connected to the RS-232C terminal?
･Is the proper cable used?
･Is the data output from the weighing device?
(Set the weighing device to stream mode.)･Is the weighing device in weighing mode?
(Is the display off, CAL mode on internal setting mode, etc?)
Confirm that the connection with the host is correct.
･Is the cable properly connected to the RS-485 terminal?
･Is a signal output from the host?
RS-232C or RS-485 communication error.
Confirm whether RS-232C or RS-485 is in error⋆1 and change
the communication settings.
Confirm the signal contents from the host.
･Is the AD-8551R set to command mode?
･Does the device address specified on the host side match the device address
set on the AD-8551R?
･Is the content sent from the host suitable for the command mode format?
Send the same content as “9-5 Communication format” from the host.
Are multiple AD-8551R set to the same device address?
Confirm the settings of the weighing device.
･Is the RUN LED flashing slowly (RS-232C communication error)⋆1 ?
Confirm the RS-232C communication settings.
･Is the weighing device output format set to the A&D standard format.
Turn the AD-8551R off and the on again. When the power is turned on, the switch
status is read and reflected in the operation.

⋆1.Refer to “8. LED (status, error display)”.

32

Command mode communication check
Phenomenon
RUN LED does not illuminate.

The RXD LED flashes before
giving instructions from the host.
RD LED does not flash.
RUN LED is flashing.
RXD LED does not flash.

The data received by the host is
corrupted.
AD-8551R settings cannot bechanged.

Confirmation and countermeasures
Confirm that the power supply is correctly supplied to the power supply terminalof the AD-8551R.
･Is the voltage appropriate?(12 to 24 VDC)
･Is the cable connected correctly?
Confirm the setting of the weighing device.
･Is the data output mode set to key mode?
Confirm that the connection with the host is correct.
･Is the cable properly connected to the RS-485 terminal?
･Is a signal output from the host?
RS-232C or RS-485 communication error.
Confirm whether RS-232C or RS-485 is in error⋆1and change thecommunication settings.
Confirm the signal contents from the host.
･Is the AD-8551R set to command mode?
･Does the device address specified on the host side match the device
address set in the AD-8551R?
･Is the content sent from the host suitable for the command mode format?
Send the same content as “10-2 Communication format” from the host.
Confirm that the weighing device is connected and set correctly.
･Is the cable properly connected to the RS-232C terminal?
･Is the correct cable used?
･Is the weighing device in weighing mode? (Is the display off, CAL mode orinternal setting mode, etc?)･Are multiple AD-8551R set to the same device address?
･After outputting a data request command to the weighing device, is the next
command output without waiting for the receipt of weighing data?
･Is the data output mode of the other weighing device set to key mode?
Turn the AD-8551R off and the on again. When the power is turned on, theswitch status is read and reflected in the operation.

⋆1.Refer to “8. LED (status, error display)”33

A&D Company, Limited

3-23-14 Higashi-Ikebukuro, Toshima-ku, Tokyo 170-0013, JAPAN
Telephone: [81] (3) 5391-6132
Fax: [81] (3) 5391-1566

A&D ENGINEERING, INC.

47747 Warm Springs Blvd, Fremont, California 94539, U.S.A.
Tel: [1] (800) 726-3364
Weighing Support:[1] (888) 726-5931

A&D INSTRUMENTS LIMITED

Inspection Support:[1] (855) 332-8815

Unit 24/26 Blacklands Way, Abingdon Business Park, Abingdon, Oxfordshire
Telephone: [44] (1235) 550420
Fax: [44] (1235) 550485

OX14 1DY

United Kingdom

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32 Dew Street, Thebarton, South Australia 5031, AUSTRALIA
Telephone: [61] (8) 8301-8100
Fax: [61] (8) 8352-7409

A&D KOREA Limited

한국에이.엔.디(주)OOO A&D RUS

OOO "ЭЙ энд ДИ РУС"서울특별시 영등포구 국제금융로6길33 (여의도동) 맨하탄빌딩 817 우편 번호 07331( 817, Manhattan Bldg., 33. Gukjegeumyung-ro 6-gil, Yeongdeungpo-gu, Seoul, 07331 Korea )전화: [82] (2) 780-4101
팩스: [82] (2) 782-4264

Почтовый адрес:121357, Российская Федерация, г.Москва, ул. Верейская, дом 17Юридический адрес: 117545, Российская Федерация, г. Москва, ул. Дорожная, д.3, корп.6, комн. 8б
( 121357, Russian Federation, Moscow, Vereyskaya Street 17 )тел.: [7] (495) 937-33-44
факс: [7] (495) 937-55-66

A&D Instruments India Private Limited( 509, Udyog Vihar, Phase- , Gurgaon - 122016, Haryana, India ): [91] (124) 4715555: [91] (124) 4715599

A&D SCIENTECH TAIWAN LIMITED.

A&D台灣分公司 艾安得股份有限公司

台湾台北市中正區青島東路 5 號 4 樓
( 4F No.5 Ching Tao East Road, Taipei Taiwan R.O.C. )Tel : [886](02) 2322-4722
Fax : [886](02) 2392-1794

A&D INSTRUMENTS (THAILAND) LIMITEDบริษัท เอ แอนด์ ดี อินสทรูเม้นท์ (ไทยแลนด์) จำกัด
168/16 หมู่ที่ 1 ตำบลรังสิต อำเภอธัญบุรี จังหวัดปทุมธานี 12110 ประเทศไทย
( 168/16 Moo 1, Rangsit, Thanyaburi, Pathumthani 12110 Thailand )Tel : [66] 20038911