Ohmmeter Replacement Guide

1. Measurement

2. Functionality

3. External Control (EXT I/O)

4. Commands

Please prepare copies of the user manuals for the old and new instruments and review the applicable sections of each.

If you do not have access to these manuals, they can be downloaded in PDF format from your myHIOKI website.

http://www.hioki.com/

Please note that this guide may be revised or up dated without notice.

(From 3560 to RM3545)

1. Measurement

(1) Resistance measurement method (difference between DC and AC)

The 3560 and RM3545 use different resistance measurement methods. The 3560 uses AC measurement, while the RM3545

uses DC measurement. These methods differ as follows:

○ Resistance (impedance) measurement can be performed using the DC or AC method.

• DC method

• AC method

1 Jan. 30, 2014users_guide_RM3545_fr_3560-E1-41E

RM3542, RM3543, RM3544, RM3545, RM3548 resistance meters

Standard digital multimeters

Standard insulation resistance meters

3561, BT3562, BT3563, 3554 Battery HiTesters

Standard LCR meters

The DC measurement method is used widely in applications such as measurement of general-purpose resistors, winding

resistance, contact resistance, and insulation resistance. Inthe DC method, the measurement setup consists of a DC power

supply and a DC voltmeter. While its simple circuitry makes it easier to increase accuracy, it is prone to measurement errors

due to electromotive force that may be present in the measurement path.

See: "Appendix 9 Effect of Thermal EMF" (RM3545 Instruction Manual p.A23)

The AC method is used when it is not possible to measure using DC, for example in impedance measurement of inductors,

capacitors, or batteries. Since an AC ohmmeter consists of an AC power supply and an AC voltmeter, it is not affected by DC

electromotive force. On the other hand, caution is necessary since results differ from those obtained using DC measurement,

for example due to components such as core loss in coils’ series equivalent resistance.

DC ohmmeter AC ohmmeterMeasurementsignalDetection voltage

DC AC

Advantages High-precision measurement is possible. Not affected by electromotive force.Reactance measurement is possible.

Disadvantages Affected by electromotive force since not capable of performing DC superimposed measurement. (Thermal EMFs can be corrected by the OVC function.)

Difficult to increase precision.

Applications DC resistance of windings such as transformers and motors, contact resistance, insulation resistance, PCB wiring resistance

Bat tery impedance, inductors , capaci tors , electrochemical measurement

Measurementrange

10-8 to 1016 10-3 to 108

Hiokiinstruments

Ohmmeters : RM3542 to RM3548DMMs : 3237 to 3238Insulation resistance meters : IR4000 series, DSM series

Battery HiTesters : 3561, BT3562, BT3563LCR meters : 3570, IM3533, IM3523, etc.

The purpose of AC resistance measurement is to eliminate the offset voltage. The RM3545’s OVC function plays the same

role. The OVC function is always on during low-power resistance measurement.

Due to the skin effect, the DC and AC values for thick materials differ (for example, at a depth of approximately 2.1 mm on a

copper skin at 1 kHz).

JIS C 5442, “Test methods of low-power electromagnetic relays for industrial control circuits,” defines applicable test methods

and includes the following items:

4.5.2(2) When using a DC voltage, measurement shall be performed by reversing switch S so as to switch the electrode polarity.

→ The described functionality corresponds to the RM3545’s OVC function.

4.5.4(1) Either a DC or AC power supply may be used for measurement, but the measured value obtained from DC measurement

shall be used in the event that there is doubt as to the accuracy of the measured value.

See: http://kikakurui.com/c5/C5442-1996-01.html

2 Jan. 30, 2014users_guide_RM3545_fr_3560-E1-41E

(2) Range structure comparison

•

○ How to set the number of display digits

Menu [P.2/2] Setting screen (SETTING) → Measurement Setting screen (MEAS) → Low-power resistance measurement (LOW POWER)

•

•

○ How to set the number of display digits

Menu [P.2/2] Setting screen (SETTING) → Measurement Setting screen (MEAS) → Number of measurement digits (Ω DIGITS)

With the low-power setting on, the RM3545 has a maximum open voltage of 20 mV, like the 3560 (when the voltage limiter is on).

3560 (For SLOW/MEDIUM, limiter is ON) RM3545 (Low-power setting is ON)

RangeDisplay range

Measurement current

Open terminal voltage

Range Display rangeMeasurement

current

Open terminal voltage

30mΩ 31.000mΩ 7.4mA

20mV max

- - - -300mΩ 310.00mΩ 1mA - - - -3Ω 3.1000Ω 100μA 1000mΩ 1200.00mΩ 1mA

20mV max30Ω 31.000Ω 10μA 10Ω 12.0000mΩ 500μA300Ω 310.00Ω 5μA 100Ω 120.000Ω 50μA3kΩ 3.1000kΩ 1.5μA 1000Ω 1200.00Ω 5μA

The 3560 and RM3545 have different range structures. When setting the range by command, an optimal range is selected based

on the setting value.

The RM3545 provides a six-digit display (when the low-power setting is on). The number of display digits can be changed (from

five to seven).

(3) Measurement leadsUse of 3560 measurement leads (9287-10, etc.) with the RM3545 is not recommended (and doing so will place the

performance of the instrument outside the accuracy guarantee). The leads that come with the RM3545 and optional

measurement leads (L2101, etc.) include a guard terminal in order to reduce the effects of external noise. Although there is

no difference in the leads’ center value (average value), use of the 3560 measurement leads with the new instrument will

make measurement more susceptible to the effects of noise, so their performance should be verified in the environment in

which they are to be used first.

If you plan to make your own measurement leads, refers to “Appendix 10: Making Your Own Measurement Leads” in the

RM3545 User Manual.

2. Functionality

(1) Hold function

(2) Manual comparator

(3) Comparator table

The RM3545 incorporates an auto-hold function. Please note that the manner in which this function operates differs from the

3560’s hold function. If you have been using the 3560’s hold function in combination with its EXT I/O functionality, change the

RM3545’s trigger source to external trigger [EXT].

○ How to change the trigger source setting

Menu [P.2/2] Setting screen (SETTING) → EXT I/O Setting screen (I/O) → Set the trigger source (TRIG SOURCE) to

external trigger (EXT).

The RM3545 does not provide functionality that corresponds to the 3560’s manual comparator function (MANU signal).

The RM3545’s panel load function corresponds to the 3560’s comparator table.

○ Panel data saved

Resistance measurement range, measurement speed, zero-adjustment, averaging, comparator, judgment tone, scaling,

temperature correction (TC), auto-hold, etc.

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3. External Control (EXT I/O)

The timing of some aspects of the RM3545’s operation differs from that of the 3560. Be sure to review the timing charts in the

RM3545’s User Manual.

(1) Switching between current sink (NPN) and current source (PNP)

The RM3545 allows you to switch between NPN and PNP operation. To control the instrument in the same way as the 3560,

set the NPN/PNP switch to NPN. The instrument ships with the switch in the NPN position. The EXT I/O mode cannot be

changed using commands.

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(2) Connector

The RM3545 connector is configured as follows:

2 14 36 58 79

202122232425262728293031323334353637

141516171819 10111213

OU

T2, BC

D7-3, B

CD

3-3O

UT0, B

CD

7-1, BC

D3-1

BIN

8, BC

D6-3, B

CD

2-3B

IN6, B

CD

6-1, BC

D2-1

BIN

4, BC

D5-3, B

CD

1-3T_E

RR

, BIN

2, BC

D5-1, B

CD

1-1T_PA

SS

, BIN

0, BC

D4-3, R

NG

_OU

T3LO

, BC

D4-1, R

NG

_OU

T1H

I, HILO

ER

R

ISO

_CO

M

ISO

_5VS

CN

_STO

PLO

AD

5LO

AD

3LO

AD

1K

EY

_LOC

KB

CD

_LOW

TRIG

, IN0

OU

T1, BC

D7-2, B

CD

3-2B

IN9, B

CD

7-0, BC

D3-0

BIN

7, BC

D6-2, B

CD

2-2B

IN5, B

CD

6-0, BC

D2-0

BIN

3, BC

D5-2, B

CD

1-2T_FA

IL, BIN

1, BC

D5-0, B

CD

1-0O

B, B

CD

4-2, RN

G_O

UT2

IN IND

EX

, BC

D4-0, R

NG

_OU

T0

EO

MIS

O_C

OM

PR

INT, IN

1M

UX

LOA

D4

LOA

D2

LOA

D0

CA

L0A

DJ

Connector: (Instrument Side)37-pin D-sub female with #4-40 screws

Mating Connectors:DC-37P-ULR (solder type) /DCSP-JB37PR (pressure weld type)Japan Aviation Electronics Industry Ltd.

Left: Current sink (NPN)Right: Current source (PNP)

(3) Signal table

Power OutputDescription 3560 RM3545 Description 3560 RM3545

Power EXT.DCV ISO_5V Comparator Hi Hi HIGround/common GND ISO_COM Comparator IN IN IN

Input Comparator Lo Lo LODescription 3541 RM3545 Comparator HiLo - HILO

TRIG(measurement start)

TRIG TRIG Measurement fault NG ERR

Zero adjustment 0ADJ 0ADJ Measurement complete EOC EOM

Printer output PRINT PRINTAnalog measurement

complete- INDEX

Calibration - CAL Range data output - RNG_OUTKey lock - KEY_LOCK BCD output * - BCDm–n

BCD low-order byte output* - BCD_LOWBIN output

- BIN0 to 9Table/panel COMP.0 to 4 LOAD0 to 5 - OB

General-purpose input - I N0, 1 General-purpose output - OUT0 to 2

Multiplexer -MUX

SCN_STOPMultiplexer -

T_PASST_FAILT_ERR

* BCDm-n: Outputs the nth bit of digit m. (BCD1-x is the lowermost digit, while BCDx-0 is the LSB.)

5 Jan. 30, 2014users_guide_RM3545_fr_3560-E1-41E

The RM3545 does not provide any functionality that corresponds to the 3560’s manual comparator function (MANU signal).

Additionally, the 3560 and RM3545 differ as follows:

[3560]

• The EOC signal turns on 1 ms after TRIG input, and the most recent judgment value is output.

• The EOC signal consists of a 1 ms pulse.

• The judgment results are updated while the EOM signal is on but are not cleared.

[RM3545]

• The EOM signal turns on once measurement starts after TRIG input, and the judgment value is output.

• Off output is generated for the EOM signal once the TRIG signal is accepted.

• The judgment results are cleared when the TRIG signal turns on.

3560: Hold state timing chart

RM3545: Timing chart when using the external trigger [EXT] setting

TRIG

EOC

Judgement result/BCD

ON

ON1ms

OFFOFF

OFF

ON/OFF ON/OFF

TRIG

EOM

Judgement result/BCD

ON

ON

OFF

OFF

OFF

OFF

OFFON/OFF

Jan. 30, 2014users_guide_RM3545_fr_3560-E1-41E

(4) Acquiring judgment results

6

4. Commands

As a rule, the RM3545 is not compatible with 3560 messages. Please replace 3560 messages with their corresponding RM3545

messages. To set the open voltage to 20 mV, turn on low-power resistance measurement (LP). The following RM3545 messages

are related to low-power resistance measurement:

(1) Message correspondence chart

3560 message Corresponding RM3545 message Explanation

Low-power resistance measurement (LP)[:SENSe:]RESistance:LP:STATe To set the open voltage to 20 mV, turn on low-power

resistance measurement (LP).[:SENSe:]RESistance:LP:STATe?

Shared commands*CLS *CLS

While shared commands can generally be used, the response from the instrument may differ.See the RM3545 Communications Command User Manual.

*ESE *ESE

*ESE? *ESE?

*ESR? *ESR?

*IDN? *IDN?

*OPC *OPC

*OPC? *OPC?

*RST *RST

*SRE *SRE

*SRE? *SRE?

*STB? *STB?

*TRG *TRG

*TST? *TST?

*WAI *WAI

Load measured values:MEASure:RESIstance? :FETCh?

The format differs. See the Communications Command User Manual.

:MEASure:BATTery?

The RM3545 does not provide voltage measurement functionality.

:MEASure:VOLTage?

:MODe

:MODe?

Zero adjustment:ADJust? :ADJust? Can be used without modifi cation.

:ZERoclear :ADJust:CLEarThe format differs. See the Communications Command User Manual.

Measurement speed:SAMPle :SAMPle:RATE The format differs. See the Communications Command

User Manual.:SAMPle? :SAMPle:RATE?

Comparator:CSET:BEEPer :CALCulate:LIMit:BEEPer

The format differs. See the Communications Command User Manual.

:CSET:BEEPer? :CALCulate:LIMit:BEEPer?

:CSET:RPARameter :CALCulate:LIMit:UPPer / :CALCulate:LIMit:LOWer

:CSET:RPARameter? :CALCulate:LIMit:UPPer? / :CALCulate:LIMit:LOWer?

:CSET:MODe The RM3545 does not provide voltage measurement functionality.:CSET:MODe?

:COMParator :CALCulate:LIMit:STATe:SYSTem:PANel:SAVE

The RM3545 does not provide a comparator table. Use the panel load function as a substitute for the comparator table. Additionally, the comparator can be used without saving panel data.

:CSET:NUMBer

:COMParator? :CALCulate:LIMit:STATe?:SYSTem:PANel:LOAD:CSET:NUMBer?

:CSET:RRANge [:SENSe:]RESistance:LP:RANGe The RM3545 uses a shared set of comparator and normal ranges. The range varies depending on whether the LP setting is on or off (when replacing the 3560, use with the LP setting on).

:CSET:RRANge? [:SENSe:]RESistance:LP:RANGe?

7 Jan. 30, 2014users_guide_RM3545_fr_3560-E1-41E

8 Jan. 30, 2014users_guide_RM3545_fr_3560-E1-41E

3560 message Corresponding RM3545 message Explanation

Comparator:CSET:VPARameter

The RM3545 does not provide voltage measurement functionality.

:CSET:VPARameter?

:CSET:VRANge

:CSET:VRANge?

:CTMode :TRIGger:SOURce The RM3545 does not have an external control terminal mode. The trigger source (internal trigger/external trigger) serves as a substitute. For timing charts, see the RM3545 User Manual.

:CTMode? :TRIGger:SOURce?

Hold:HOLD [:SENSe:]HOLD:AUTO / :TRIGger:SOURce The RM3545’s hold function acts as an auto-hold

function. To stop operation after each measurement, set the trigger source to external trigger.:HOLD? [:SENSe:]HOLD:AUTO? / :TRIGger:SOURce?

Measurement range:RRANge [:SENSe:]RESistance:LP:RANGe The format differs. See the Communications Command

User Manual.The range varies depending on whether the LP setting is on or off (when replacing the 3560, use with the LP setting on).

:RRANge? [:SENSe:]RESistance:LP:RANGe?

:AUTorange [:SENSe:]RESistance:RANGe:AUTO

:AUTorange? [:SENSe:]RESistance:RANGe:AUTO?

:VRANge

:VRANge?

Hold:SENSecheck [:SENSe:]RESistance:LP:CONTactcheck The format differs. See the Communications Command

User Manual.The range varies depending on whether the LP setting is on or off (when replacing the 3560, use with the LP setting on).

:SENSecheck? [:SENSe:]RESistance:LP:CONTactcheck?

Supply frequency:FERQuency :SYSTem:LFRequency The format differs. See the Communications Command

User Manual.:FERQuency? :SYSTem:LFRequency?

Communication setting:HEADer :SYSTem:HEADer The format differs. See the Communications Command

User Manual.:HEADer? :SYSTem:HEADer?

Lock function:LIMit

The RM3545 does not have a limiter function.:LIMit?

:LOCK:EXTernalThe RM3545 does not have an I/O lock function.

:LOCK:EXTernal?

:LOCK:KEY :SYSTem:KLOCk The format differs. See the Communications Command User Manual.:LOCK:KEY? :SYSTem:KLOCk?

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All information correct as of Jan. 30, 2014. All specifications are subject to change without notice.

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