Servo Wiring and Tuning detailed How To example Mesa 7i77.

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1 year 7 months ago #324913 by tommy
Replied by tommy on topic Servo Wiring and Tuning detailed How To example Mesa 7i77.
Yes, it is step/dir driver.

If it helps, here are .ini and .hal sections, related to this axis:
Code:
[AXIS_X] MIN_LIMIT          = -1 MAX_LIMIT          = 1100 MAX_VELOCITY       = 170 MAX_ACCELERATION   = 200 [JOINT_0] CARD               = 0 TAB                = 0 AXIS               = X TYPE               = LINEAR HOME               = 0.000 MAX_VELOCITY       = 170 MAX_ACCELERATION   = 200 #PID_MAX_VEL        = 10 BACKLASH           = 0.000 STEP_INVERT        = False DIR_INVERT         = False STEPGEN_MAX_VEL    = 220 STEPGEN_MAX_ACC    = 250 DIRSETUP           = 200 DIRHOLD            = 200 STEPLEN            = 800 STEPSPACE          = 800 SCALE              = -1998.6 ENCODER_SCALE      = -1998.6 MIN_LIMIT          = -1.0 MAX_LIMIT          = 1100 FERROR             = 10 MIN_FERROR         = 7 HOME_OFFSET        = -4.0 HOME_SEARCH_VEL    = -10 HOME_LATCH_VEL     = 2 HOME_USE_INDEX     = NO HOME_IGNORE_LIMITS = YES HOME_SEQUENCE      = 1 DEADBAND           = 0.001 P                  = 100 I                  = 0 D                  = 15 BIAS               = 0 FF0                = 0 FF1                = 1 FF2                = 0.01 MAX_OUTPUT         = 0
Code:
# PID Setup setp    pid.x.Pgain        [JOINT_0](P) setp    pid.x.Igain        [JOINT_0](I) setp    pid.x.Dgain        [JOINT_0](D) setp    pid.x.bias        [JOINT_0](BIAS) setp    pid.x.FF0        [JOINT_0](FF0) setp    pid.x.FF1        [JOINT_0](FF1) setp    pid.x.FF2        [JOINT_0](FF2) setp    pid.x.deadband    [JOINT_0](DEADBAND) setp    pid.x.maxoutput [JOINT_0](MAX_OUTPUT) #setp    pid.x.error-previous-target True # limit stepgen velocity corrections caused by position feedback jitter #setp    pid.x.maxerror    [JOINT_0](MAX_ERROR) # joint-0 enable chain net x-index-enable  <=>  pid.x.index-enable net x-enable       => pid.x.enable net x-output       => pid.x.output net x-pos-cmd      => pid.x.command net x-vel-fb       => pid.x.feedback-deriv net x-pos-fb       => pid.x.feedback # Joint 0 Step Gen signals/setup setp hm2_[MESA](BOARD).0.stepgen.00.dirsetup        [JOINT_0](DIRSETUP) setp hm2_[MESA](BOARD).0.stepgen.00.dirhold            [JOINT_0](DIRHOLD) setp hm2_[MESA](BOARD).0.stepgen.00.steplen            [JOINT_0](STEPLEN) setp hm2_[MESA](BOARD).0.stepgen.00.stepspace        [JOINT_0](STEPSPACE) setp hm2_[MESA](BOARD).0.stepgen.00.position-scale     [JOINT_0](SCALE) setp hm2_[MESA](BOARD).0.stepgen.00.maxvel            [JOINT_0](STEPGEN_MAX_VEL) setp hm2_[MESA](BOARD).0.stepgen.00.maxaccel        [JOINT_0](STEPGEN_MAX_ACC) setp hm2_[MESA](BOARD).0.stepgen.00.step_type 0 setp hm2_[MESA](BOARD).0.stepgen.00.control-type 1 # ---closedloop stepper signals--- net x-pos-cmd    joint.0.motor-pos-cmd net x-output                             => hm2_[MESA](BOARD).0.stepgen.00.velocity-cmd net x-enable     joint.0.amp-enable-out  => hm2_[MESA](BOARD).0.stepgen.00.enable # ---Encoder feedback signals/setup--- setp    hm2_[MESA](BOARD).0.encoder.00.counter-mode 0 setp    hm2_[MESA](BOARD).0.encoder.00.filter 1 setp    hm2_[MESA](BOARD).0.encoder.00.index-invert 0 setp    hm2_[MESA](BOARD).0.encoder.00.index-mask 0 setp    hm2_[MESA](BOARD).0.encoder.00.index-mask-invert 0 setp    hm2_[MESA](BOARD).0.encoder.00.scale  [JOINT_0]ENCODER_SCALE net x-pos-fb               <=  hm2_[MESA](BOARD).0.encoder.00.position net x-vel-fb               <=  hm2_[MESA](BOARD).0.encoder.00.velocity net x-pos-fb               =>  joint.0.motor-pos-fb net x-index-enable    joint.0.index-enable  <=>  hm2_[MESA](BOARD).0.encoder.00.index-enable net joint-0-pos-rawcounts        <=  hm2_[MESA](BOARD).0.encoder.00.rawcounts

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1 year 7 months ago #324992 by tommy
Replied by tommy on topic Servo Wiring and Tuning detailed How To example Mesa 7i77.
Rising up STEPGEN_MAX_ACC significantly, gave me much much better response, now I'm well below 0.01mm f-error during g-code run! 

 
The following user(s) said Thank You: tommylight, ktm950adv

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8 months 3 weeks ago #342688 by besriworld
Replied by besriworld on topic Servo Wiring and Tuning detailed How To example Mesa 7i77.
I am trying to configure the spindle as a C-axis, but I am having a problem and cannot find a solution.
Could someone please take a look at my configuration and the video and give me some advice?
I was not able to post this in the original lathe thread.





#########################
# AXIS C JOINT 2
#########################

setp  pid.c.Pgain     [JOINT_2](P)
setp  pid.c.Igain     [JOINT_2](I)
setp  pid.c.Dgain     [JOINT_2](D)
setp  pid.c.bias      [JOINT_2](BIAS)
setp  pid.c.FF0       [JOINT_2](FF0)
setp  pid.c.FF1       [JOINT_2](FF1)
setp  pid.c.FF2       [JOINT_2](FF2)
setp  pid.c.deadband  [JOINT_2](DEADBAND)
setp  pid.c.maxoutput [JOINT_2](MAX_OUTPUT)
setp  pid.c.error-previous-target true

net c-index-enable    =>  pid.c.index-enable
net c-enable          =>  pid.c.enable
net c-pos-cmd         =>  pid.c.command
net c-spindle-pos-fb  =>  pid.c.feedback
net c-output          <=  pid.c.output 

# ---PWM Generator signals/setup---

268 net c-output            =>  hm2_7i98.0.pwmgen.00.value
269 net c-pos-cmd           <=  joint.2.motor-pos-cmd
270 net c-enable            <=  joint.2.amp-enable-out
271 # enable _all_ sserial pwmgens
272 #net c-enable            =>  hm2_7i92.0.7i77.0.1.analogen

276 net c-spindle-pos-fb    <=  hm2_7i98.0.encoder.02.position
277 net c-spindle-vel-fb    <=  hm2_7i98.0.encoder.02.velocity
278 net c-spindle-pos-fb    =>  joint.2.motor-pos-fb
279 #net c-index-enable     joint.0.index-enable <=> hm2_7i92.0.encoder.06.index-enable
280 net c-pos-rawcounts     <=  hm2_7i98.0.encoder.02.rawcounts

282 # ---setup home / limit switch signals---

284 net c-home-sw           =>  joint.2.home-sw-in
285 net c-neg-limit         =>  joint.2.neg-lim-sw-in
286 net c-pos-limit         =>  joint.2.pos-lim-sw-in


[AXIS_C]
MAX_VELOCITY     = 360
MAX_ACCELERATION = 500
MIN_LIMIT        = -900.0
MAX_LIMIT        = 900.0

[JOINT_2]
TYPE             = ANGULAR
HOME             = 0.0
FERROR           = 1000.0
MIN_FERROR       = 500.0
MAX_VELOCITY     = 360
MAX_ACCELERATION = 500

P        = 0.0000001
I        = 0.
D        = 0.
FF0      = 0.98
FF1      = 0
FF2      = 0
BIAS     = 0
DEADBAND = 0.1
MAX_OUTPUT = 10

ENCODER_SCALE    = -40
OUTPUT_SCALE     = 10
OUTPUT_MIN_LIMIT = -10
OUTPUT_MAX_LIMIT = 10

MIN_LIMIT = -1000
MAX_LIMIT = 1000

HOME_OFFSET   = 0.0
HOME_SEQUENCE = 1

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8 months 3 weeks ago #342689 by tommylight
Replied by tommylight on topic Servo Wiring and Tuning detailed How To example Mesa 7i77.

P = 0.0000001
I = 0.
D = 0.

Why?

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8 months 3 weeks ago - 8 months 3 weeks ago #342693 by besriworld
Replied by besriworld on topic Servo Wiring and Tuning detailed How To example Mesa 7i77.
If you have time, please watch the video.
Even with a very small P value, the axis starts to oscillate.

PS. I understand that Linuxcnc is fighting with the internal PID controller of the servo driver.
Last edit: 8 months 3 weeks ago by besriworld.

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8 months 3 weeks ago #342711 by tommylight
Replied by tommylight on topic Servo Wiring and Tuning detailed How To example Mesa 7i77.
Remove the dots after the 0 for I and D.
From video, definitely something wrong, but no idea what, that is not normal oscillation as it is moving way to much back and forth.
Do some plots using halscope for command and f-error

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