Measurement Limits

Min.

Typ.

Max.

Units

AC Voltage

85.0

-

264.0

Volts

AC Current, 10A models

➀

AC Current, 32A models

➀

AC Current, 100A models

➀

0.00

0.00

0.0

-

-

-

9.999

32.00

100.0

Amperes

Amperes

Amperes

Active Power: 10A models

0

0

0

-

-

-

999.9

9999

26.4

Watts

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) (Measurement Category II)

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’ Watts

➄

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)

Hex Nut Tightening Torque

0.14 N-m (20 ozf-in)

➀Specified 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.

➄Applies to 10A and 32A models only.

Performance/Functional Specifications

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

ORDERING INFORMATION

ACM20-2-AC1-R-C

10A, 85-264Vac Supply (Power Factor Reading)

ACM20-5-AC1-R-C

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

ACM20-4-AC1-R-C

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

ACM20-2-AC1-R-F-C

10A, 85-264Vac Supply (Frequency Reading)

ACM20-5-AC1-R-F-C

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

ACM20-4-AC1-R-F-C

100A, 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 multifunction 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, AMPS, WATTS, power factor

(PF), or line frequency on ‘-F’ HERTZ models.

While the ACM20 displays the rms value of line voltage and line

current, the VOLTS reading has an upper limit of 140Hz (-3db point),

which means rectangular-shaped voltage waveforms, and waveforms

with sharp transitions, will read lower than their true-rms value. For

example, a square wave line voltage will read approximately 1-2%

lower, a triangle wave will read 3% lower, and a modified sine wave

will read 18% lower. The oscillograms on page seven illustrate typical

ACM20 VOLTS readings when powered from four ac waveforms.

The 140Hz bandwidth limit does not apply to the WATTS reading nor

to the AMPS reading. The circuitry used for these two measurements

has an upper bandwidth of 14kHz. ACM20 power meters are mains

operated devices designed to measure ac currents and voltages,

within the specified limits previously noted. DC currents and voltages

will not be measured accurately.

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.

!

ACM20 Series

Four-Function AC Power Meters

www.murata-ps.com/dpm

email: sales@murata-ps.com

03 Mar 2011

MPM_ACM20 Series.A09 Page 2 of 6