Stepper Motor Speed is too slow

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1 year 3 weeks ago #336128 by richcolvin
10 in/sec is well beyond what we ever need; indeed, I'd be surprised if we need to achieve even 0.1 in/sec.  That was just an attempt to see if changing that value would drive the needed speed.

As for commenting out the PID stuff, that was due to the way I understood them to be only needed for servo motors, and not for stepper motors.  This is based on my reading of section 2.13.2. Servos in the manual ( linuxcnc.org/docs/stable/html/config/ini...ub:ini:sec:joint-num ).

Quite probably, I misunderstood the manual.

I will add the PID stuff back into the configuration and test tomorrow, and then report back.

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1 year 3 weeks ago #336165 by richcolvin
ACTIONS TAKEN:
I re-added these lines to the HAL file:

setp pid.u.Pgain                            [JOINT_4]P
setp pid.u.Igain                            [JOINT_4]I
setp pid.u.Dgain                            [JOINT_4]D
setp pid.u.bias                             [JOINT_4]BIAS
setp pid.u.FF0                              [JOINT_4]FF0
setp pid.u.FF1                              [JOINT_4]FF1
setp pid.u.FF2                              [JOINT_4]FF2
setp pid.u.deadband                         [JOINT_4]DEADBAND
setp pid.u.maxoutput                        [JOINT_4]MAX_OUTPUT

and these to the INI file

BIAS                 = 0.0
DEADBAND             = 0.00005
MAX_OUTPUT           = 10.0
OUTPUT_SCALE         = 1.000
OUTPUT_OFFSET         = 0.000
P                    = 1000.0
I                    = 0.0
D                    = 0.0
FF0                  = 1.0
FF1                  = 1.0
FF2                  = 0.0

RESULTS:
That seems to have fixed the speed problem I was having. However, a new problem has now arisen:  When I initiate the move, either by jogging (e.g., 0.1") or using the Gcode (e.g., G0 u-0.1 f1), the stepper motor
  1. moves the piece some distance (let's assume it is 0.1"),
  2. reverses back that same distance,
  3. then re-executes steps 1-2 until I stop LinuxCNC.

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1 year 3 weeks ago #336172 by PCW
Replied by PCW on topic Stepper Motor Speed is too slow
FF0 should be 0

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1 year 3 weeks ago #336207 by richcolvin
Peter, thank you for the guidance.  Once I re-enabled the PID stuff, things worked as expected.

I used the auto tuning steps and from there have been able to get to a good state.

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