Hi. I'm running a small projects which involves finding current change due to various dynamic loads imosed on a DC motor. I'm using arduino with motor shield and 10k pot to adjust direction and speed of the motor. My motor is a 12V 30:1 gear DC (EMG 30)
I'm using Picoscope for my scope and PicoLog to lod my data. I get tremendously large noise when I measure my voltages across. I have installed an 0.1 uF capacitor across the motor terminals and two 0.047 uF caps - across each lead and the motor casing (shied) - but it didn't help.
Also, when using picoscope, what is the right way to connect the red and black clips across the motor - I may be doing it wrong (it does not allow to connect the two across the resistor as it gives the grounding effect).
Excuse me for my poor electrical knowledge, but I hope some more experineced folks here woud give me some tips on how I can get rid of this noise.

Regards

 

Tell us more about how you are powering this motor--certainly not a 10K potentiometer
Sounds like the a PWM motor drive control
What is the motor current rating and base speed?
A simple low-pass filter for your voltage and/or current measurement may do.

 

Tell us more about how you are powering this motor--certainly not a 10K potentiometer
Sounds like the a PWM motor drive control
What is the motor current rating and base speed?
A simple low-pass filter for your voltage and/or current measurement may do.

Thanks for your response jimkeith.
I'm using a 12 V DC supply from my AC-DC adapter.
Yes PWM is used to control the drive.
Rated current 530 mA Rated speed 170 rpm
The thing is, PicoScope 2203 does not allow for a low pass filter...
Here is the motor data: http://www.robot-electronics.co.uk/htm/emg30.htm

Any more suggestions??