Hi All,
I had a cnc with 3 DC motors (1.32mH and 0.7 Ohm) connected to 3 DG4S.
Everything was working fine, but after some maintenance to the X axis, the drive is loosing steps (0.5mm and more at random iteration), and the same problem is on Y axis that we dont' touch.
I tried to retune the PID with servoconfig, but it has random spikes that send the driver in error generating the position error.
I partially solved the problem (in long steps 1000) increasing the sampling time to 15 or more, but when testing on smaller steps (100) the system is instable
I checked the encoders with an oscilloscope, and the seem's working fine. I notice a spiky noise across all the channels and power (Image1). [Yellow A, Purple B, Cyan A_, Green B_],
The noise is present also if the encoreder is disconnected (Detail with disconnected encoder) so I think it's generated by the DG4S on the power line. [Yellow A, Purple B, Green is Power supply]
The noise, in some cases exeed the 1.6V, so should it be confused by the logic for a changing ede?
The frequence of the noise is around 17.6kHz, very near to the sampling base of 60us -> 16.66kHz (but should be the same because the measure I made is not so precise)
Any suggestion is welcome!