AC Current RMS measurement

[Humada33]

I am trying to measure the AC Current of an industrial motor between the motor drive and the motor. The signal I am getting has a significant amount of noise and when  I use the basic RMS vi I get ~ half the value that I should be getting. Can anyone tell me if I need to apply additional processing or if there is a better solution? The equipment I am using is

CompactDAQ Chassis with a 9219 module

The transducer is a LEM LF-205-s/sp3 which outputs a current signal in the range of 0-100mA and using a 100 ohm resistor to get a voltage of 0-10V

The environment is industrial with several other machines operating in the vicinity of the test equipment

The current measured with an AC DMM is 4A which should result in a voltage of .4 volts. The reading from the DAQMx is ~.2 volts.

Any help is much appreciated.

Thank you

Chris

[Henrik_Volkers]

Please provide more information.

Samplerate, no. of points, why not post the code?

A small(!) png or jpg from a waveform diagram (OK, not that small, it should at least have one main period 😉 ?

How connected to the board? (type of wire, shielding topology, single ended/differential input?? )

Quality of power supply of the LEM sensor, filter, decoupling, buffer right at the sensor? (BTDT that's important!)

Depending on the driver you might have very high frequencies in your AC current. Do some measurements at highest possible samplerate or use a scope to check.