STEPLEN STEPSPACE time for Bergerda AC servo driver

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1 year 7 months ago #324009 by tommy
I'm trying to reach 10000mm/min max velocity on three axis, but lowering STEPLEN and STEPSAPECE below 1000 nanoseconds, following error shows up immediately.
Based on driver specs Maximum frequency of input is 1MHZ (Differential motion).

I believe mesa 7i95T isn't limiting factor here!?

My current values:
DIRSETUP          = 200
DIRHOLD            = 200
STEPLEN            = 1000
STEPSPACE       = 1000
SCALE                = 2000

 
 

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1 year 7 months ago - 1 year 7 months ago #324012 by PCW
Are you using 7I95T encoder feedback?

Can you post your hal/ini files?

Reducing the steplength and stepspace parameters
will not directly cause a following error, though reducing them
will allow higher speeds that may expose other limits.

The 7I95T is capable of generating up to 10 MHz step rates

 
Last edit: 1 year 7 months ago by PCW.

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1 year 7 months ago #324014 by tommy
Yes I'm using encoder feedback for all axis.

ini & hal files attached

If you will check files, there are JOINT 0,1 and 6 on which I would like to increase velocity.

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1 year 7 months ago - 1 year 7 months ago #324016 by PCW
I would make these changes in the hal file and try again:

Comment out all these (XYZ etc) lines.
That is, change this:

net x-vel-fb hm2_[MESA](BOARD).0.encoder.00.velocity => pid.x.feedback-deriv

to this:

#net x-vel-fb hm2_[MESA](BOARD).0.encoder.00.velocity => pid.x.feedback-deriv

(and so on for y,z etc)

Then add these lines:

setp hm2_[MESA](BOARD).0.dpll.01.timer-us -200
setp hm2_[MESA](BOARD).0.encoder.timer-number 1
setp hm2_[MESA](BOARD).0.stepgen.timer-number 1
setp hm2_[MESA](BOARD).0.encoder.sample-frequency 20000000

 
Last edit: 1 year 7 months ago by PCW.

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1 year 7 months ago - 1 year 7 months ago #324047 by tommy
setp hm2_[MESA](BOARD).0.encoder.sample-frequency 20000000 gives me error on startup (pin not exist).

So I tried with:
setp hm2_[MESA](BOARD).0.encoder.muxed-sample-frequency 20000000

but result is same, when lowering STEPLEN and STEPSPACE from 1000 to 800, immediate following error.

A have also attached my hal_load file to check
Last edit: 1 year 7 months ago by tommy.

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1 year 7 months ago #324054 by PCW
You may have to increase the following error limits a bit and plot the
commanded and feedback positions and joint following error with halscope
to determine why you are getting a following error:

Possibilities:

Drive does not work with shorter step signals

Encoder feedback does not work at higher speeds

Instability/tuning issues


 

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