Measurement Limits

Min.

Typ.

Max.

Units

AC Voltage

85.0

-

264.0

Volts

AC Current, 32A models

➀

0.00

-

32.00

Amperes

AC Current, 100A models

➀

0.0

-

100.0

Amperes

Active Power: 32A models

0

0

-

-

9999

26.4

Watts

kW

Frequency

47.0

-

63.0

Hz

Power Factor

.00

1.00

-

-

Overcurrent Rating

➁

1.5 x rated full-scale current

Performance

Sampling Rate

2-3 samples / sec

Voltage Accuracy

➂

±1%

Current Accuracy

➂

±1%

Power Accuracy

➂

±2%

Frequency Accuracy

➂

±0.1

Hz

Power Factor Accuracy

±3%

Measurement Bandwidth

140Hz (Voltage), 14kHz (Current)

Temperature Drift (0 to 60ºC)

0.5 Counts/ºC

Zero-Current Reading (within 2 sec.)

0.00

Amps

Zero-Power Reading (within 2 sec.)

0

Watts

Supply Voltage (TB1)

All Models – 47-63 Hz

85

120

264

Vac

Supply Current

➃

All Models

35

50

110

mA

Power Supply Terminal Block

Wire Size

16-22AWG, solid or stranded

Insulation Strip Length

6.4mm (0.250 in)

Screw Tightening Torque

0.4Nm (3.6 lb-in)

Rated Voltage

300Vac

Display

Display Type and Size

4 Digit LED, 9.14mm (0.36in) high

Overrange Indication

Flashing ‘9999’

Decimal Point Selection

Automatically Set

Physical/Environmental

Operating Temperature

0

–

+60

°C

Storage Temperature

–40

–

+75

°C

Humidity (non-condensing)

0

–

85

%

Dimensions

See mechanical specifications

Weight: 32A models

1.3oz (37.9g)

1.5oz (43.5g)

①Specified full-scale currents are those passing through the power meter’s built-in current

transformer’s primary load-circuit.

➁The overcurrent rating of 1.5 x the rated full-scale current is a continuous rating and applies

to the current passing through the built in current transformer. Accuracy is guaranteed up to

the rated current.

➂ACM20 Power Meters are calibrated with near full-scale 60Hz sine-wave inputs.

➃All specified maximum supply currents are steady state; larger surge currents can occur at

initial application of line power.

Performance/Functional Specifications

Typical at TA=+ 25ºC, 120Vac @ 60Hz, unless otherwise noted

ORDERING INFORMATION

ACM20-4-AC1-R-C

100A, 85-264Vac Supply (Power Factor Reading)

ACM20-5-AC1-R-C

32A, 85-264Vac Supply (Power Factor Reading)

ACM20-4-AC1-R-F-C

100A, 85-264Vac Supply (Frequency Reading)

ACM20-5-AC1-R-F-C

32A, 85-264Vac Supply (Frequency Reading)

TECHNICAL NOTES

IMPORTANT! To ensure safe and reliable operation, ACM20 power

meters must be installed and serviced by qualified technical person-

nel. Contact Murata Power Solutions if there is any doubt regarding

their installation or operation.

1. Measurement Type: ACM20 series multi-function AC power meters

employ a precision energy metering integrated circuit and a low-

power microcontroller to measure and display the rms voltage and

current, active(real) power, power factor (or line frequency on ‘–F’

suffix models) of ac mains supplies from 47-63Hz. Please note,

ACM20 power meters use the voltage present at their TB1 terminal

block and the secondary current of their built-in current transformer

L1 to calculate and then display VOLTS, WATTS, power factor (PF), or

line frequency on ‘-F’ HERTZ models.

2. Basic Operation: Upon application of ac power to TB1, the unit will

first perform a self-test routine and then continuously display ac volts

with the VOLTS LED annunciator illuminated. The display will remain

in the VOLTS mode as long as the front panel 'SEL' button is not

touched.

After the unit powers up to normal operation in the VOLTS reading

mode, momentarily (approximately one second) touching the ‘SEL’

button on the unit’s front panel three times in succession will cycle

the display to AMPS, WATTS, and end at PF (or HERTZ for ‘–F’ mod-

els). Momentarily touching ‘SEL’ a fourth time will return the display

back to the VOLTS reading mode.

Holding the 'SEL' button down for 3 seconds will place the unit in a

continuous auto-cycling mode, and the display will repetitively scroll

through all four measurements, with each measurement remaining

displayed for 3 seconds.

When the continuous auto-cycling mode is initially selected, the unit

will briefly display ‘Auto On’ before continuous cycling begins. Mo-

mentarily touching the ‘SEL’ button again will cause the unit to briefly

display ‘Auto OFF’ before it returns to the fixed VOLTS reading mode.

3. Calibration: Due their digital design, ACM20 power meters cannot be

calibrated in the field. ACM20 power meters are factory-calibrated to

meet their specified accuracies with the supplied L1 current trans-

former. Use of any other current transformer will produce significant

errors for the Amps, Watts, and Power Factor measurements.

Contact Murata Power Solutions if additional information is required

regarding calibration, setup, or any other technical issue pertaining to

ACM20 power meters.

ACM20 Series

Four-Function AC Power Meters

www.murata-ps.com/dpm

email: sales@murata-ps.com

08 Oct 2009

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