Changing Scale Factors in a Series 4000 Circuit Monitor



Need to change the scaling for measurement value on a Powerlogic Meter using register writes

Product Line
CM3000 Series, CM4000 Series, PM800 Series

Application requiring a change in scaling to measurement where read/write register command can be made through the front display or serial communications.

The scale factors for the Voltmeter, Ammeter, or Wattmeter can be adjusted. This can be done by using the Protected Command Interface in the circuit monitor. You can use a modbus communication tool or make the change from the front panel.  Changes may be made to one or multiple scale factor values.


  1. Write the value 9020 to register 8000 to enter the setup mode.
  2. Write the desired scale factor value to the appropriate register. See Table 1 below. Repeating this step for each subsequent scale factor change can change multiple scale factors.
  3. Write the value 1 to register 8001 to save the changes made in Step 2.
  4. Write the value 9021 to register 8000 to exit the setup mode.

The circuit monitor will reset. The power values will now be displayed on the front panel of the Circuit Monitor with the new scale.
NOTE: The above 5-step procedure can be accomplished with a single Write statement from Control>Diagnostics>Read/Write register window. Example below show how to change the Ammeter and Voltmeter scale factor simultaneously.

Table 1

Scale Group Range Scale Factor Register
A - Ammeter per phase -2 to 1 3209
B - Ammeter Neutral -2 to 1 3210
C - Ammeter Ground -2 to 1 3211
D - Voltmeter -1 to 2 3212
E - Voltmeter Neutral -1 to 2 3213
F - Wattmeter -3 to 3 3214
H - Transient Voltages 0 to 3 3216

Table 2
Scale Factor Definition
-3 SCALE BY 0.001
-2 SCALE BY 0.01
-1 SCALE BY 0.1
1 SCALE BY 10.0
2 SCALE BY 100
3 SCALE BY 1000

See the attached POWERLOGIC Application Tip document.