Instructions

4.2 Functions
Device description
5191 / 07/2021 enBENNING CM 2-120
4.2 Functions
Use the rotary switch to switch the device on (desired measuring function) or off (“OFF”).
The device confirms each operation of keys and the rotary switch with an acoustic signal.
Invalid keystrokes are confirmed with a double beep. The device switches off automatically after
approx. 20minutes (APO, Auto-Power-Off). To switch the device back on, first set the rotary
switch to switch position “OFF” and then set the desired measuring function.
4.2.1 “ACHFR/ DCAZERO” key
The “ACHFR/ DCAZERO” key has three functions.
“MODE” function
Press the “ACHFR/ DCAZERO” key to select the second, third or fourth function of the
respective rotary switch position.
Figure9: “MODE” function
“HFR(AC)” function (low-pass filter)
The “HFR(AC)” function is intended to connect a low-pass filter (high-frequency suppression)
during AC current or AC voltage measurement. With this low-pass filter, it is possible to filter out
high-frequency pulses, e.g. on pulsed motor drives.
Press and hold the “ACHFR/ DCAZERO” key for approx.2s to enable or disable the function.
With the function being enabled, the “HFR” symbol appears on the digital display.
The limiting frequency (-3dB) of the filter is fg=800Hz. When reaching the limiting
frequencyfg, the displayed value is lower by a factor of 0.707 than the actual value without
filter.
Without low-pass filter With low-pass filter
Table4: Low-pass filter