Hi,
I'm trying to use my Galil DMC-4070 to communicate an analog +10V signal to an amplifier in order to drive it. The amplifier seems to be driving the stage with a minimal current, and that current is based on the noise being sent to the amplifier from Galil's Analog Motor Command signal (+MCMD, -MCMD).
Plugging in an oscilloscope to the two points (+MCMD, -MCMD) directly from the Galil board (without any connection to the amplifier itself), I am seeing strange sinusoidal waveforms and noise. Amplitudes are reaching about 50-100mV while off, so that's slightly noisey, but when I send the active motor signal (SHA), Galil seems to be sending a low-voltage, approx. 300Hz Sine wave on top of this noise, creating a strange noise signal I've never seen before.
This is all before sending any other kind of command, either.
All of my coefficients for this analog signal (KPA, KDA, KIA, FVA, FAA) are set equal to zero, so I know I'm not trying to command any kind of signal unintentionally when activating the motor (SHA).
Any idea where this noise could be coming from or how to eliminate it? Is there anything else on Galil I should be mindful of to try and eliminate any of this strange noise?
IanPMI on 05/15/2015 - 13:06
Sorry, the Galil controller is a DMC-4173, not a DMC-4070 (if that even exists.)
MattK on 05/26/2015 - 12:06
Hello Ian,
As with any electrical system, some noise is expected. However, the noise level expected on the motor command DAC should not be high enough to cause inadvertent movements. You mention measuring the MCMD +/- lines. The DMC-4173 does not include differential motor command lines in it's various options. Therefore I am curious as to which pins you are measuring specifically.