【1】Read First: Safety Information
We thank you for your purchasing our product, the battery-driven
insulation resistance tester.
This is a DC resistance tester developed under the principle to provide
new and unique design and function for the measurement of insulation
resistance of each kind of electric equipments. Since this tester
generates high voltage, we recommend that you read this instruction
manual thoroughly, and treat the tester correctly and safely.
The symbols used on this tester and in this instruction manual denotethe following meanings:
Be careful as the high voltage is impressed.
Be careful because there is a possibility of bodily injury or thedestruction of equipment.

13. Use test leads matching the measurement category of the object
measured. If the measurement categories of the instrument and test leads
were different, the lowest measurement category would be applied.
14. When handling equipment containing a hazardous live part, besure to wear insulative protection gear to prevent accidents. Also
be sure to observe your local and national safety regulations.
15. Do not attempt any alterations of original specifications.
16. To ensure safety and maintain accuracy, calibrate and check thetester at least once a year.
17. Indoor use.
18. Do not use the instrument in a place where corrosive or explosive
gas is produced.
19. To prevent the protection function of the tester from being spoiled,
do not use it in a method other than specified.

WARNING

DM509S/DM1009S/PDM509S
INSULATION RESISTANCE TESTERINSTRUCTION MANUAL

Dempa Bldg., 4-4 Sotokanda 2-Chome
Chiyoda-ku, Tokyo, JapanTo ensure that the meter is used safely, follow all safety and operating instructions.
11. Never use tester for high power or high voltage circuit.
12. Pay special attention when measuring the voltage of AC 33 Vrms
(46.7 V Peak) or DC 70 V or more to avoid injury.
13. Disconnect power source of the measured circuit before
measuring insulation resistance.
14. High voltage is generated while measuring insulation resistance.
Be cautions of electric shock.
15. After measuring insulation to avoid electric shock. Be sure todischarge the high voltage charged.
16. Never apply an input signal exceeding the maximum rating input value.
17. Never use tester for measuring the line connected withequipment (i.e. motors) that generates induced or surge voltage
since it may exceed the maximum allowable voltage.
18. Never use tester if the tester or test leads are damaged or broken.
19. Never use uncased tester.
10. Always keep your fingers behind the Barriers on the probe when
making measurements.
11. Be sure to disconnect the test pin from the circuit when changing the function.
12. Never use tester with wet hands or in a damp environment.

・Function control knob and MΩ (insulation resistance) measuring switch
by operating these two switches, the functions and ranges can be
set as shown below.
Position of Function Control Knob
500 V/1000 MΩ
DM509S
DM1009S
1000 V/2000 MΩ
PDM509S
500 V/100 MΩ
500 V/1000 MΩ
DM509S
DM1009S
1000 V/2000 MΩ
PDM509S
500 V/100 MΩ
BATTERY CHECKDC 60 VMΩ
Measuring
Switch ( * )Set Range(Function)OFF

AC 600 V range

AC
600 V
AC
600 V

ON
ON
OFF

Body compartment
Test leadcompartment

To carry while heldby handA**
Join by hook

5.1

− 4 −

1. The MΩ measurement should be performed as quickly as possible
to prevent the internal parts from heating. Particularly, when measuringresistance between 0 MΩ to the center of scale, perform eachmeasurement within 20 seconds and leave an equivalent interval tothe measuring time before proceeding to the subsequent measurement.
2. The no-load voltage is within 1.25 times the rated measuring
voltage.
1)

2)⑥ Turn on the MΩ measuring switch.
(See [4] Description of Functions)⑦ Read the indicated value. Use the MΩ scale.
⑧ Turn off the MΩ measuring switch.
⑨ Discharge the high voltage charged in the measuring object. See
5.4 Discharge Function.
⑩ First remove the red test pin from the object measured, andthen disconnect the black alligator clip.
⑪ Be sure to turn the function control knob to the position of OFF.

Rated measuring voltage
500 V1000 V
500 V

1. Rated measuring voltage should be selected by a measuring
object. For example, 125 V rated measuring voltage should be
used for the object, AC input voltage of which is 100 V.

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− 9 −

− 12 −

Pointer is on left of battery
check scale（BATT）?

Yes

No
Turn function control knob
and MΩ switch to OFF.

No

Short alligator clip (or test pin) on black
test lead with test pin on red test lead.

Pointer is at almost 0 MΩ
position of insulation resistancescale ?
Yes
Turn MΩ measuring switch andfunction control knob to OFF.

5.2 How to Check Battery (BATTERY CHECK)
Prior to MΩ (insulation resistance) measurement, be sure to check thebattery. A consumed battery will cause not only measurement errors
but danger due to erroneous measurement.
For checking methods, refer to 5.1 Start-up Check.

2.Remove components such as semi-conductors and apparatuses
from the circuit of measuring object to avoid damages whenwithstand of the object is unknown or lower than rated measuring
voltage of a resistance insulation tester, especially in case of theobjects you measure connected with PCs or computers.

1) Prior to requesting repair, please check the following:
Capacity of the battery, polarity of installation and discontinuity of thetest leads.
2) Repair during the warranty period:
The failed meter will be repaired in accordance with the conditions
stipulated in 6-1 Warranty and Provision.
3) Repair after the warranty period has expired:
In some cases, repair and transportation cost may become higher
than the price of the product. Please contact Sanwa authorized agent/ service provider in advance.
The minimum retention period of service functional parts is 6 years
after the discontinuation of manufacture. This retention period is therepair warranty period. Please note, however, if such functional parts
become unavailable for reasons of discontinuation of manufacture,etc., the retention period may become shorter accordingly.
4) Precautions when sending the product to be repaired
To ensure the safety of the product during transportation, place theproduct in a box that is larger than the product 5 times or more involume and fill cushion materials fully and then clearly mark “Repair
Product Enclosed” on the box surface. The cost of sending andreturning the product shall be borne by the customer.
6-3 SANWA web site
http://www.sanwa-meter.co.jp
E-mail: exp_sales@sanwa-meter.co.jp【7】Battery Replacement

Red
Pin-type adapter Barriers Test pins
Black
Barriers

Alligator clip:Black
CAT.Ⅲ 600 V

5.3

Measurement of MΩ (Insulation Resistance)
WARNING

1. Never apply a voltage to the measuring terminal when the tester
is in the MΩ measuring range.
2. Prior to measurement, disconnect the measuring object (circuit)from the power supply.
3. Prior to measurement, make sure no voltage is applied to thecircuit to measure by the AC 600 V range.
4. During measurement, a high voltage is generated. Do not touch
the test pin, clip and measuring object.
5. The tester and measured circuit have been charged by high voltage
immediately after the measurement. Be careful not to get electric
shock.
6. There is a possibility of an accident of electric shock. After themeasurement, be sure to discharge the high voltage charged in
the measuring object. (See 5.4 Discharge Function)
CAUTION
1. When the object measured is grounded, usually connect the black
EARTH (ground) test lead to the grounded side and the red LINE
test lead to the circuit. (When this connection is used, a measurement
value becomes smaller than a value obtained by the reverse
connection.)
2. To prevent a measuring error, keep the test lead connected to
the LINE side out of contact with the measuring object and ground(earth).
3. The insulation resistance varies largely depending on temperatureand humidity. It is also influenced by a voltage to apply (measuring
voltage).
Normally as temperature, humidity and voltage increase, theinsulation resistance decreases.

Do not check the battery for more than 5 seconds.

− 6 −

− 7 −

5.4 Discharge Function
1) Reason of a need to discharge
For safety, high voltage remaining in capacitive measuring objects
such as capacitors and electric wire must be discharged to prevent
accidents.
2) Discharging method (This procedure follows the step ⑧ of 5.3-4)① When the MΩ measurement has been completed, turn off only
the MΩ measuring switch with the test pin and the alligator clip
connected to the measuring object.
② Then the pointer deflects to the right and its deflection becomes
smaller as time passes (indicating the charged charge is being
discharged).
③ When the pointer stops at zero (∞ of the MΩ scale) and discharge
has been completed, conduct the steps ⑩ and ⑪ of 5.3-4)

5.6 Measurement of ACV (AC voltage) (Measuring range is the AC 600 V range only)

5.5 Measurement of DCV (DC voltage) (Measuring range is the DV 60 V range only)

1)

1)

CAUTION

Removable
test pin covers

When not covered

Black

Release push switch and replace test
lead with new one and re-check.
If replacement does not work, repair

WARNING
1. Do not apply a voltage exceeding the maximum rated voltage of
60 VDC.
2. Keep in mind the warnings of 5.6 described earlier.

Selection of a measuring range
Turn the function control knob to (MΩ) / AC 600 V position.
4) Measuring method① Power off the measuring object.
② Insert the black measuring cord to which the black alligator clip (orblack pin-type adapter) is attached into the EARTH (ground)measuring terminal, and the red measuring cord to which the red
pin-type adapter is attached into the LINE measuring terminal.
③ Turn the function control knob to a desired rated measuring
voltage range.
④ Connect the black alligator clip to the object measured. Usuallyconnect the EARTH (ground) measuring terminal to the groundingside.
⑤ Connect the tip of the red pin-type adapter to the other side of
the object measured.
CAUTION : If the meter deflects in this state, the measuring
object is charged. Be sure to remove the voltage
prior to measurement.

6-1 Warranty and Provision
Sanwa offers comprehensive warranty services to its end-users and toits product resellers. Under Sanwa's general warranty policy, each
instrument is warranted to be free from defects in workmanship ormaterial under normal use for the period of one (1) year from the dateof purchase.
This warranty policy is valid within the country of purchase only, andapplied only to the product purchased from Sanwa authorized agent or
distributor.
Sanwa reserves the right to inspect all warranty claims to determine
the extent to which the warranty policy shall apply. This warranty shallnot apply to test leads, disposables batteries, or any product or parts,
which have been subject to one of the following causes:
1. A failure due to improper handling or use that deviates from the
instruction manual.
2. A failure due to inadequate repair or modification by people otherthan Sanwa service personnel.
3. A failure due to causes not attributable to this product such as fire,
flood and other natural disaster.
4. Non-operation due to a discharged battery.
5. A failure or damage due to transportation, relocation or dropping after
the purchase.
6-2 Repair
Customers are asked to provide the following information whenrequesting services:
1. Customer name, address, and contact information
2. Description of problem
3. Description of product configuration
4. Model Number
5. Product Serial Number
6. Proof of Date-of-Purchase
7. Where you purchased the product

Turn on MΩ
switch.

Connect black test lead to EARTH terminal
and red test lead to LINE terminal.

3)【6】After-Sales Service

Turn function control knob
to DC 60 V/BATTERY CHECK.

DamagedStop using.
Main unit andRepair it.
test lead damaged
in appearance?
Place main unit
No damaged
horizontally,
No adjust pointer 0
position adjuster
Pointer at 0 position
with screwdriverwhen main unit is placed
to bring pointerhorizontally?
to 0 position.
Yes

− 5 −

Measuring object
Measurement of insulation resistance (MΩ ) of electric equipment
and circuits.
Rated measuring voltage
Model
DM509S
DM1009S
PDM509S

Replacebattery.
See【7】
Battery
Replacement.

Check appearance and pointer 0 position.

Normal. Proceed to measurement.

WARNING

Removable test pin covers
When not covered : CAT.Ⅱ 1000 V
When attached : CAT.Ⅲ 600 V− 3 −Start-up Check

1. Do not use a damaged tester or test lead.
2. Make sure test lead wiring is not broken.
3. When testing the continuity of a test lead, the measuring terminals
are under a high voltage. Be careful of electric shock.
4. To prevent electric shock and battery consumption, be sure toturn the M Ω measuring switch and function control knob to OFF
after measurement.

Earth side measuringterminal (EARTH)
R
RTH)

Test Lead(TL-509S)

2.2 Features
・ The measured voltage is maintained until the low insulation resistancevalue at the rated current specified in IEC61557-2.
・It is equipped with the discharge function.
・It is equipped with the M Ω (insulation resistance) measuring switchthat enables both one-shot and continuous measurement.

Turn on MΩ measuring switch.

【5】Measuring Method

Line side measuringterminal (LINE)

Function control knob

2.1 Applications
・DC insulation resistance tester to measure the insulation resistanceof electric lines and electric equipment.

Turn function control knob to
AC 600 V・250 V/500 ΩM.

Raise left end
Press right end

Battery check
scale

Red

Check measuring lead wiring breakage.

(OFF when the finger is released)② Continuously ON when the left end of the lever is raised. (OFFwhen it is laid down)

DCV scale

Measuring cords

Check battery.

Body securing band

ACV scaleAMΩ(insulation
resistance)measuringswitch【2】Applications and Features

Check start.

To hang from the neckduring measurement

P
PointerP
Pointer
0 position
adjuster

Maximum overload
protection input
AC 720 V
AC 600 V

Before starting measurement, check the“appearance”“pointer,0
position”( * ),“battery”and“measuring lead”in this order. (*The pointer0 position is the 0 position of the DC 60 V scale or ∞ position of theMΩ scale.)MΩ measuring switch is turned on by the following operation.
*①The ON
only when the right end of the lever is pressed with a finger.

REFERENCE

Maximu rating
input value
AC 600 V
DC 60 VHow To Use Carrying Case
During measurement, set the case as illustrated and hang it fromthe neck.

0500 V/1000 MΩ
1000 V/2000 MΩ
500 V/100 MΩ
BATTERY CHECKDC 60 V・Meter zero position adjustment
If the meter pointer is not on the ∞ graduation line of the MΩ scale
when the function control knob is at OFF, adjust the zero position
with a screwdriver.

Function(Range)ACV (600)
DCV (60)− 2 −・Lid turns in
direction at pivot the A.
・Lay it along the bottomof the box and secure it
by hooks marked by*MΩ scale(insulation resistance)

Maximum Overload Protection Input− 1 −02-1711 2040 2040

【4】Description of Functions

CAUTION
Remove components such as semi-conductors and apparatuses from the circuit ofmeasuring object to avoid damages when withstand of the object is unknown orlower than rated measuring voltage of a resistance insulation tester, especially incase of the objects you measure connected with PCs or computers.

【3】Frontrront
View and Name of Each Partrrt

Measuring object
DC voltages of batteries, etc. can be measured.
Also, the tester can be used to check the presenceof DC voltage prior to MΩ measurement.
2) Measuring method① Insert the black measuring cord to which the black
alligator clip (or black pin-type adapter) is attachedinto the EARTH (ground) measuring terminal, and thered measuring cord to which the red pin-type adapter
is attached into the LINE measuring terminal.
② Turn the function control knob to DC 60 V.
③ Connect the black alligator clip to the－ side of the object (circuit) measured,and connect the tip of the red pin-type adapter to the + side.
④ Read the indicated value on the DCV scale.
⑤ First remove the red test pin from the object measured, and thendisconnect the black alligator clip from it.
⑥ Turn the function control knob to the position of OFF.

WARNING
1. Do not apply a voltage exceeding the maximum rated voltage of 600 VAC.
2. During measurement, do not operate the function control knob.
3. Do not measure a voltage with the MΩ measuring switch beingpressed or raised.
4. When the circuit to measure has a breaker, measure the voltage
on the secondary side (load side).
5. To prevent electric shock, do not touch the metal part of the pin plug and clip.
CAUTION
AC voltages of waveforms other than sinusoidal waveforms andfrequencies other than 50 to 60 Hz will cause an indication error.
Measuring object
Sinusoidal AC voltages (ACV)such as lighting line voltages
can be measured.
2) Measuring method① Insert the black measuring cord
to which the black alligator clip
(or black pin-type adapter) is
attached into the EARTH (ground)measuring terminal, and the redmeasuring cord to which the red
pin-type adapter is attached into
the LINE measuring terminal.
② Turn the function control knob to AC 600 V.
③ Connect the black alligator clip to the earth (grounding) side of
the object measured, and connect the tip of the red pin-typeadapter to the charging side of the object measured.
④ Read the indicated value on the ACV scale.
⑤ First remove the red test pin from the object measured, andthen disconnect the black alligator clip from it.
⑥ Turn the function control knob to the position of OFF.

− 10 −− 11 −【8】Specifications
8.1 Measurement Range and Accuracy
7.1 Accuracyassurance: 23±5 ℃ 75 ％RH max.
No condensation
7.1 Attitude: Horizontal ±5°. External magnetic field: Not present.
Battery voltage: Within the range in which the battery
power is effective.
Model

DM509S

DM1009S

PDM509S

Rated measuring voltage Large numeral : 1st effective measuring scaleMΩ
Measuring value
Small numeral : 2nd effective measuring scale
Insulation
Resistance 500 V 0.5-1-500- 1000 V 1-2-1000- 500 V 0.05-0.1range 1000 MΩ 1000 MΩ 2000 MΩ 2000 MΩ 100 MΩ 50-100 MΩ

（）

ACV range

0~600 VDCV range

0~60 V・MΩrange
1st effective
measurement range : ±5 % of reading
2nd effective
measurement range : ±10 % of reading
0, ∞ scale: ±0.7 % of scale length
Accuracy
No load voltage: ＋25－0 % of rated measuring voltage
Rated current: 1~1.2 mA
Short circuit current : max 2.9 mA・ACV range (50/60 Hz sine wave): ±5 % of full scale① Remove two battery lid
Screwssecuring screws.
Battery lid② Replace the consumed
battery that is connected toSnap terminal
the snap terminal with a
new one.
③ Set the batter y in theoriginal place and secure the
6LR61 Battery(6LF22)
battery lid with screws.
Be sure to turn the function control knob to the position of
OFF prior to replacing the battery.
Be sure to use the alkaline battery 6LR61(6LF22) (9 V).

＊Factory-preinstalled battery
A battery for monitoring is preinstalled before shipping, therefore it may
run down sooner than the battery life specified in the instruction manual.
The "battery for monitoring" is a battery to inspect the functions andspecifications of the product.

− 13 −− 14 −

・DCV range: ±5 % of full scale

Operating Within ±30 %(Maximum value tolerated by IEC standard)
instrumental Variation-causing factors [E1: Attitude. E2: Supply voltage.
uncertainty E3: Temperature]

8.2 General Specifications
AC rectifying method : Half-wave rectification(Mean value indication rms value converted)
Meter specification : Inner-pole type taut-band system, 24 μA (PDM509S:48 μA)
Battery consumption : Checked by BATTERY CHECK range.
Allowable temperature/humidity range : 23±5 ℃, 75 % RH max., no condensation.
Service temperature/humidity : 0～43 ℃, 80 % RH max., no condensation.
Storage temperature/humidity : -10～50 ℃, 70 % RH max., no condensation.
Service ambient condition : Altitude 2000 m max., environmental pollution Ⅱ.
Power supply: Layer built type alkaline battery 6LR61(6LF22) x 1(9 V)Max. power consumption : 2.0 W~2.8 W at MΩ range
Battery life
: When the lower limit measurement resistance value thatcan maintain the rated output voltage is measured and
if one cycle for the measurement is defined as ON for 5
seconds and OFF for 25 seconds, the battery life is 500 cycles.
Degree of IP: IP20EMC Directive, RoHS Directive : IEC61326 (EMC), EN50581(RoHS)
Safety: IEC61010-1, IEC61010-2-030 CAT.Ⅲ600 V *IEC61010-2-033, IEC61010-031* Measurement Category III : Line from the primary side or branch of equipment which directly(CAT. III) takes in electricity from a distribution board to the receptacle.

Year of manufacture : The first two digits of the serial number on
the bottom of this product indicate the lasttwo digits of the year.
Size and Mass
: 144(H ) x 99 (W ) x 43 (D ) mm, approx. 310 g
Accessories: Test lead TL-509S, 1 set
Instruction manual, 1 Carrying case C-09S, 1【9】Storage
CAUTION
・The panel and the case are not resistant to volatile solvent andmust not be cleaned with thinner or alcohol.
For cleaning, use dry, soft cloth and wipe it lightly.
・The panel and the case are not resistant to heat. Do not place theinstrument near heat-generating devices (such as a soldering iron).
・Do not store the instrument in a place where it may be subjected
to vibration or from where it may fall.
・ For storing the instrument, avoid hot, cold or humid piaces orplaces under direct sunlight or where condensation is anticipated.
− 15 −