Servo Jog PNCCONF Open loop test

I did post this earlier in Setup but I think it should be here.

I'm running MESA 7I48 and servo drives and motors. The encoder is on the back of the motor. If I turn the motor, CC or CCW by hand, I get the axis value incrementing on the DRO. When using the test in the config program and stepping the motor, I get a nice smooth rotation, around 3 rpm in the CCW direction, however I get about 300 rpm in the CW direction.

I have put a meter on the input to the Servo card and this is what I have.
CW a pulse around 0.5 volt The hm2_5i20_0_encoder.00.position increments by 2 units
CCW around 5 volt. The hm2_5i20_0_encoder.00.position increments by 20 units

Not sure where to go from here ?

Is this a step and direction drive or analog servo?
7i48...I guess analog servo.

Can you try the using linuxcnc rather then the test...servo test is fairly new.
And then please post your config files....could be a scaling problem.

Chris M

I tried a second motor and servo and have the same issue.
I have attached the files.

I'm using MCG inc DMC 6D drives set to voltage mode.
See www.ebay.com/itm/MCG-DMC6D-BRUSH-TYPE-PW...DMC-6D-/330537737719

I have to get this going. I see from my profile that I joined 5 years ago and still don't have a machine up and running. Hmm.

Hi Andy

Thanks for the reply. The settings are the default from a new installation of 2.7.
I have not changed them (except X where P=1) . I assume that they would be at least a starting point.

The P=50 is quite strange as from experience P is normally around 1-5

Does anything in the setup explain why the + jog works and the - jog runs away ?

Thanks Wallace.

Wrong PWM mode for a 7I48 can behave this way

Ok My mistake. When using PncConf it says the 7i48 daughter board requires UDM type generators and a PWM base frequency of 24 khz. I did not see the UDM requirement.

I now have the open loop test working, I can step + and - fine.

Trying the Tune Axis I get

PNCconf encountered an error. The following information may be useful in troubleshooting:

Traceback (most recent call last):
File "/usr/lib/pymodules/python2.7/pncconf/pages.py", line 1322, in on_update_tune_params
self.t.update_tune_test_params()
File "/usr/lib/pymodules/python2.7/pncconf/tests.py", line 858, in update_tune_test_params
' enc_scale':self.enc_scale,
KeyError: 'enc_scale'

One I have it operating is the question. I can tune from inside the program but at startup Acc, Velocity, following errors etc are the critical items to tune.

Is there a place to post the error so can be looked at?

Has anyone done a stand alone program that can adjust these parameters real time? It would be exceptionally useful addition. .

Thanks Wallace

You can adjust PID tuning parameters live via the calibrate menu in Axis