Mesa 7i92+7i76+7i85S

OK so the 7I76 is not being detected (no sserial communications)

Possible reasons for no communication:
1. Cable power jumpers on 7I92  and 7I76 miss-matched
2. Cable errors
3. 7I76 not connected to  P2
4. 7I76 jumpered for setup, not operation
5. Hardware issues (damaged 7I92 or 7I76)

This was the problem  4. 7I76 jumpered for setup, not operation now linuxcnc starting.
Another problem I dont see any voltage on TB4 pins 1, 2, 3 when I start spindle and setup for example 3000rpm  
I see only 0,4Volt on pins 5 and 6 

Note that TB4 pins 1,2,3 do not output any voltage by themselves,
they are intended to replace a potentiometer so typically
TB4.3 goes to the VFDs +10V, TB4.1 goes to VFD analog GND
and TB4.2 goes to the VFD analog input (the potentiometer wiper connection)

Likewise, TB4s ENA and DIR outputs do not output voltages,
they are simply switches.

I connect all to the lathe.
Get out setp pid.N.maxerror .0005 and   net N-vel-cmd => pid.N.command-deriv
The linear scales read ok.
I cant properly ajust step motors.
If I setup P to 1000 get big oscilations and must lower to 10.
Ballscrew is 2505
Linear scales 0,001

 

P will be much smaller for encoder feedback because the delays from step
command to actual motion limit the maximum stable gain. I would also expect
FF1 t be exactly 1.000 since this should get the step generator moving properly
even without feedback.

Also did you get this all working with stepgen feedback before changing to encoder feedback? Is the encoders scale properly?

Encoder scale is ok 1000 for 0,001 linear scale
I dont try working with stepgen feedback before changing to encoder feedback.
Which line delete for see stepgen feedback?
On steppers I can chose microstep settings up to 51200 and for now I setup 1000 is correct?

to change to stepgen feedback, you would change

net x-pos-fb <= hm2_7i92.0.encoder.02.position
to
net x-pos-fb <= hm2_7i92.0.stepgen.00.position-fb

(for x)

Note that the encoder and stepgen scaling and direction must be equal
(that is whatever microstep ratio you use the step scale must be set correctly)

I set to net x-pos-fb <= hm2_7i92.0.stepgen.00.position-fb
And play with settings.
Now settings is:
STEPGEN_MAXVEL = 30
STEPGEN_MAXACCEL = 1000
P = 30
I = 0
D = 0
FF0 = 0.004
FF1 = 1
FF2 = 0.002
BIAS
After that axis moving smmotly and F.error is about 0,004
When I set back to net x-pos-fb <= hm2_7i92.0.encoder.02.position  
Now problem is when I move for example 1mm axis going 1.01mm and back -0.01mm and finally is 1mm
Or moving -0.5 axis going -0.51 and back 0.01
Must set STEP_SCALE = 1020  becouse axis dont make 1mm only 0.98mm (this was set with only stepgen feedback and watching dial indicator)

 

I have problem with X axis.
I change to stepgen feedback.
For correct moving with dial indicator must setup steper scale to 850     and moving 0.1mm the move is 0.1mm
Stepper drive is set to 4000 and ballscrew is 1204 
When I back to encoder feedback the axis moving .02 more than expected,   moving 0,1mm axis move 0.12mm

Play all day with pid and not lucky.
Setting steper scales I use test bar from micrometer 200mm long, now the scale is 100% correct.
Disconecting steppers and moving axis with hand, dro show ok encoder scale is ok.
Read several topics but don find answer for my problem.
If axis is setting to stepgen feedback and move them 1mm axis stop on 1mm if I setting to encoder feedback and move 1mm axis going 1.02mm and back 0.02mm
Any help?