Motor encoder scaling

You can't change the scale to tune the axes.
You must set the scale so the DRO and movement are in agreement.
Then you tune the PID

When I did that the motors went nuts. 3 tonnes of machine jumping around aint pretty. I don't know where to start in PID when they are doing that.

So after checking the raw encoder count of 8000 (as Tommy instructed) how do I utilize that in the axis scaling? I'm obviously missing something.

This is the last setup I tried and would continue on PID tuning but the DRO/Machine scaling is way out.
Z MKD041 encoder scale 24000
Y MKD041 encoder scale 24000
X MKD071 encoder scale 32000

Peter

See my last message
Axis scaling is what linuxcnc uses to know how much to move to get to a requested position. It must be correct and there is only one correct setting.

PID tuning is what linuxcnc uses to correct the requested command based on the current feedback position (ie smooth accurate movement)

Untuned position loop can be very violent.

I suggest googling linuxcnc PID tuning.
Unfortunately it's a little black magic and the best information is spread around in wikis and forum posts
eg:
wiki.linuxcnc.org/cgi-bin/wiki.pl?PWM_Servo_Amplifiers

Chris

Does the raw encoder (8000/rev) count have anything to do with how I scale the axis.
Peter.

yes. scale means counts per unit of travel ie 20000 counts per inch

This 'counts' includes any encoder counts, gearing, lead screw pitch and or electronic dividing of the encoder counts.

ie A motor with a 2000 counts per revolution encoder tied directly to a 10 revolution per inch lead screw(10 tpi) = 20000 scale

2000 X 10 = 20000 counts per inch

same thing but wiih a 2:1 gear ratio added between the motor and lead screw:

2000 (encoder counts) X 10 (10 TPI) X 2 (gear ratio) = 40000 counts per inch

Chris

I understand what your saying but I cant get to work in Pncconf.

Peter