yet another Joint.0.Following error (but I promised I searched a lot first)

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29 Aug 2020 22:21 - 29 Aug 2020 22:23 #179976 by jhandel
Howdy all,
I am working out my first axis on this machine, its a retrofit AC Servo based machine with encoders. I am using an 7i76e + 7i89 and a 5 Axis Bob. I have the X axis wired up and pulses are moving it (yah) the encoder is returning data (yah). However between .3 and .6mm of movement I get Joint 0 Following Error.

Here are some machine/servo facts.
1) 5000 steps/rotation
2) 5mm sweep ball screw
3) 2000 encoder pulses/ unit (or 10000 encoder pulses/rotation)
a) encoders are using RS-422, tried TTL and nothing was recording
4) testing as confirmed hm2.0.7i76e.0.encoder.00.count is bang on the correct number of encoder pulses for the distance moved before it fails out...
5) I have some scope data (see below) & I did a latency histogram (40 minutes with two glxgears running and a long youtube video streaming)
6) yes I have wifi on here
7) I am using dedicated ethernet and have the 7i76e using 10.10.10.10 ip
8) I have tried several different FERROR and MIN_FERROR values
a) min_ferror that isn't 0 causes the ferror to crawl upwards when nothing is moving
b) negative min_ferror actually causes the axis to move VERY slowly
c) any FERROR over about 500 causes the error to happen almost instantly and I can have to press the "power" multiple times before it will stay on long enough to try to jog the axis
d) FERROR of around 10 "turns on" very stably but the machine movement is significantly smaller than

Here is the HAL (Most of these settings are "out of the box" from PNCCONFIG and seem pretty conservative compared to the settings the controller I am replacing had)
# Generated by PNCconf at Thu Aug 27 19:47:31 2020
# Using LinuxCNC version:  UNAVAILABLE
# If you make changes to this file, they will be
# overwritten when you run PNCconf again

loadrt [KINS]KINEMATICS
loadrt [EMCMOT]EMCMOT servo_period_nsec=[EMCMOT]SERVO_PERIOD num_joints=[KINS]JOINTS
loadrt hostmot2
loadrt hm2_eth board_ip="10.10.10.10" config="num_encoders=10 num_pwmgens=0 num_stepgens=6 sserial_port_0=0000xx" 
setp    hm2_7i76e.0.watchdog.timeout_ns 5000000
loadrt pid names=pid.x,pid.y,pid.z,pid.s
loadrt abs names=abs.spindle
loadrt lowpass names=lowpass.spindle
loadrt scale names=scale.spindle

addf hm2_7i76e.0.read          servo-thread
addf motion-command-handler   servo-thread
addf motion-controller        servo-thread
addf pid.x.do-pid-calcs       servo-thread
addf pid.y.do-pid-calcs       servo-thread
addf pid.z.do-pid-calcs       servo-thread
addf pid.s.do-pid-calcs       servo-thread
addf scale.spindle            servo-thread
addf abs.spindle              servo-thread
addf lowpass.spindle          servo-thread
addf hm2_7i76e.0.write         servo-thread



#*******************
#  AXIS X JOINT 0
#*******************

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
setp   pid.x.maxerror .0005

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

# Step Gen signals/setup

setp   hm2_7i76e.0.stepgen.00.dirsetup        [JOINT_0]DIRSETUP
setp   hm2_7i76e.0.stepgen.00.dirhold         [JOINT_0]DIRHOLD
setp   hm2_7i76e.0.stepgen.00.steplen         [JOINT_0]STEPLEN
setp   hm2_7i76e.0.stepgen.00.stepspace       [JOINT_0]STEPSPACE
setp   hm2_7i76e.0.stepgen.00.position-scale  [JOINT_0]STEP_SCALE
setp   hm2_7i76e.0.stepgen.00.step_type        0
setp   hm2_7i76e.0.stepgen.00.control-type     1
setp   hm2_7i76e.0.stepgen.00.maxaccel         [JOINT_0]STEPGEN_MAXACCEL
setp   hm2_7i76e.0.stepgen.00.maxvel           [JOINT_0]STEPGEN_MAXVEL

# ---closedloop stepper signals---

net x-pos-cmd    <= joint.0.motor-pos-cmd
net x-vel-cmd    <= joint.0.vel-cmd
net x-output     <= hm2_7i76e.0.stepgen.00.velocity-cmd
net x-enable     <= joint.0.amp-enable-out
net x-enable     => hm2_7i76e.0.stepgen.00.enable

# ---Encoder feedback signals/setup---

setp    hm2_7i76e.0.encoder.00.counter-mode 0
setp    hm2_7i76e.0.encoder.00.filter 1
setp    hm2_7i76e.0.encoder.00.index-invert 0
setp    hm2_7i76e.0.encoder.00.index-mask 0
setp    hm2_7i76e.0.encoder.00.index-mask-invert 0
setp    hm2_7i76e.0.encoder.00.scale  [JOINT_0]ENCODER_SCALE

net x-pos-fb               <=  hm2_7i76e.0.encoder.00.position
net x-vel-fb               <=  hm2_7i76e.0.encoder.00.velocity
net x-pos-fb               =>  joint.0.motor-pos-fb
net x-index-enable    joint.0.index-enable  <=>  hm2_7i76e.0.encoder.00.index-enable
net x-pos-rawcounts        <=  hm2_7i76e.0.encoder.00.rawcounts

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

net home-x     =>  joint.0.home-sw-in
net x-neg-limit     =>  joint.0.neg-lim-sw-in
net x-pos-limit     =>  joint.0.pos-lim-sw-in

#*******************
#  AXIS Y JOINT 1
#*******************

setp   pid.y.Pgain     [JOINT_1]P
setp   pid.y.Igain     [JOINT_1]I
setp   pid.y.Dgain     [JOINT_1]D
setp   pid.y.bias      [JOINT_1]BIAS
setp   pid.y.FF0       [JOINT_1]FF0
setp   pid.y.FF1       [JOINT_1]FF1
setp   pid.y.FF2       [JOINT_1]FF2
setp   pid.y.deadband  [JOINT_1]DEADBAND
setp   pid.y.maxoutput [JOINT_1]MAX_OUTPUT
setp   pid.y.error-previous-target true
setp   pid.y.maxerror .0005

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

# Step Gen signals/setup

setp   hm2_7i76e.0.stepgen.01.dirsetup        [JOINT_1]DIRSETUP
setp   hm2_7i76e.0.stepgen.01.dirhold         [JOINT_1]DIRHOLD
setp   hm2_7i76e.0.stepgen.01.steplen         [JOINT_1]STEPLEN
setp   hm2_7i76e.0.stepgen.01.stepspace       [JOINT_1]STEPSPACE
setp   hm2_7i76e.0.stepgen.01.position-scale  [JOINT_1]STEP_SCALE
setp   hm2_7i76e.0.stepgen.01.step_type        0
setp   hm2_7i76e.0.stepgen.01.control-type     1
setp   hm2_7i76e.0.stepgen.01.maxaccel         [JOINT_1]STEPGEN_MAXACCEL
setp   hm2_7i76e.0.stepgen.01.maxvel           [JOINT_1]STEPGEN_MAXVEL

# ---closedloop stepper signals---

net y-pos-cmd    <= joint.1.motor-pos-cmd
net y-vel-cmd    <= joint.1.vel-cmd
net y-output     <= hm2_7i76e.0.stepgen.01.velocity-cmd

net y-enable     <= joint.1.amp-enable-out
net y-enable     => hm2_7i76e.0.stepgen.01.enable

# ---Encoder feedback signals/setup---

setp    hm2_7i76e.0.encoder.01.counter-mode 0
setp    hm2_7i76e.0.encoder.01.filter 1
setp    hm2_7i76e.0.encoder.01.index-invert 0
setp    hm2_7i76e.0.encoder.01.index-mask 0
setp    hm2_7i76e.0.encoder.01.index-mask-invert 0
setp    hm2_7i76e.0.encoder.01.scale  [JOINT_1]ENCODER_SCALE

net y-pos-fb               <=  hm2_7i76e.0.encoder.01.position
net y-vel-fb               <=  hm2_7i76e.0.encoder.01.velocity
net y-pos-fb               =>  joint.1.motor-pos-fb
net y-index-enable    joint.1.index-enable  <=>  hm2_7i76e.0.encoder.01.index-enable
net y-pos-rawcounts        <=  hm2_7i76e.0.encoder.01.rawcounts

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

net y-home-sw     =>  joint.1.home-sw-in
net y-neg-limit     =>  joint.1.neg-lim-sw-in
net y-pos-limit     =>  joint.1.pos-lim-sw-in

#*******************
#  AXIS Z JOINT 2
#*******************

setp   pid.z.Pgain     [JOINT_2]P
setp   pid.z.Igain     [JOINT_2]I
setp   pid.z.Dgain     [JOINT_2]D
setp   pid.z.bias      [JOINT_2]BIAS
setp   pid.z.FF0       [JOINT_2]FF0
setp   pid.z.FF1       [JOINT_2]FF1
setp   pid.z.FF2       [JOINT_2]FF2
setp   pid.z.deadband  [JOINT_2]DEADBAND
setp   pid.z.maxoutput [JOINT_2]MAX_OUTPUT
setp   pid.z.error-previous-target true
setp   pid.z.maxerror .0005

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

# Step Gen signals/setup

setp   hm2_7i76e.0.stepgen.02.dirsetup        [JOINT_2]DIRSETUP
setp   hm2_7i76e.0.stepgen.02.dirhold         [JOINT_2]DIRHOLD
setp   hm2_7i76e.0.stepgen.02.steplen         [JOINT_2]STEPLEN
setp   hm2_7i76e.0.stepgen.02.stepspace       [JOINT_2]STEPSPACE
setp   hm2_7i76e.0.stepgen.02.position-scale  [JOINT_2]STEP_SCALE
setp   hm2_7i76e.0.stepgen.02.step_type        0
setp   hm2_7i76e.0.stepgen.02.control-type     1
setp   hm2_7i76e.0.stepgen.02.maxaccel         [JOINT_2]STEPGEN_MAXACCEL
setp   hm2_7i76e.0.stepgen.02.maxvel           [JOINT_2]STEPGEN_MAXVEL

# ---closedloop stepper signals---

net z-pos-cmd    <= joint.2.motor-pos-cmd
net z-vel-cmd    <= joint.2.vel-cmd
net z-output     <= hm2_7i76e.0.stepgen.02.velocity-cmd
net z-enable     <= joint.2.amp-enable-out
net z-enable     => hm2_7i76e.0.stepgen.02.enable

# ---Encoder feedback signals/setup---

setp    hm2_7i76e.0.encoder.02.counter-mode 0
setp    hm2_7i76e.0.encoder.02.filter 1
setp    hm2_7i76e.0.encoder.02.index-invert 0
setp    hm2_7i76e.0.encoder.02.index-mask 0
setp    hm2_7i76e.0.encoder.02.index-mask-invert 0
setp    hm2_7i76e.0.encoder.02.scale  [JOINT_2]ENCODER_SCALE

net z-pos-fb               <=  hm2_7i76e.0.encoder.02.position
net z-vel-fb               <=  hm2_7i76e.0.encoder.02.velocity
net z-pos-fb               =>  joint.2.motor-pos-fb
net z-index-enable    joint.2.index-enable  <=>  hm2_7i76e.0.encoder.02.index-enable
net z-pos-rawcounts        <=  hm2_7i76e.0.encoder.02.rawcounts

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

net z-home-sw     =>  joint.2.home-sw-in
net z-neg-limit     =>  joint.2.neg-lim-sw-in
net z-pos-limit     =>  joint.2.pos-lim-sw-in

#*******************
#  SPINDLE
#*******************

setp   pid.s.Pgain     [SPINDLE_0]P
setp   pid.s.Igain     [SPINDLE_0]I
setp   pid.s.Dgain     [SPINDLE_0]D
setp   pid.s.bias      [SPINDLE_0]BIAS
setp   pid.s.FF0       [SPINDLE_0]FF0
setp   pid.s.FF1       [SPINDLE_0]FF1
setp   pid.s.FF2       [SPINDLE_0]FF2
setp   pid.s.deadband  [SPINDLE_0]DEADBAND
setp   pid.s.maxoutput [SPINDLE_0]MAX_OUTPUT
setp   pid.s.error-previous-target true
setp   pid.s.maxerror .0005

net spindle-index-enable  <=> pid.s.index-enable
net spindle-enable        =>  pid.s.enable
net spindle-vel-cmd-rpm     => pid.s.command
net spindle-vel-fb-rpm      => pid.s.feedback
net spindle-output        <=  pid.s.output

# Step Gen signals/setup

setp   hm2_7i76e.0.stepgen.05.dirsetup        [SPINDLE_0]DIRSETUP
setp   hm2_7i76e.0.stepgen.05.dirhold         [SPINDLE_0]DIRHOLD
setp   hm2_7i76e.0.stepgen.05.steplen         [SPINDLE_0]STEPLEN
setp   hm2_7i76e.0.stepgen.05.stepspace       [SPINDLE_0]STEPSPACE
setp   hm2_7i76e.0.stepgen.05.position-scale  [SPINDLE_0]STEP_SCALE
setp   hm2_7i76e.0.stepgen.05.step_type        0
setp   hm2_7i76e.0.stepgen.05.control-type     1
setp   hm2_7i76e.0.stepgen.05.maxaccel         [SPINDLE_0]MAX_ACCELERATION
setp   hm2_7i76e.0.stepgen.05.maxvel           [SPINDLE_0]MAX_VELOCITY

net spindle-enable          =>  hm2_7i76e.0.stepgen.05.enable
net spindle-vel-cmd-rps     =>  hm2_7i76e.0.stepgen.05.velocity-cmd
# ---Encoder feedback signals/setup---

setp    hm2_7i76e.0.encoder.09.counter-mode 0
setp    hm2_7i76e.0.encoder.09.filter 1
setp    hm2_7i76e.0.encoder.09.index-invert 0
setp    hm2_7i76e.0.encoder.09.index-mask 0
setp    hm2_7i76e.0.encoder.09.index-mask-invert 0
setp    hm2_7i76e.0.encoder.09.scale  [SPINDLE_0]ENCODER_SCALE

net spindle-revs             <=   hm2_7i76e.0.encoder.09.position
net spindle-vel-fb-rps       <=   hm2_7i76e.0.encoder.09.velocity
net spindle-index-enable     <=>  hm2_7i76e.0.encoder.09.index-enable

# ---setup spindle control signals---

net spindle-vel-cmd-rps        <=  spindle.0.speed-out-rps
net spindle-vel-cmd-rps-abs    <=  spindle.0.speed-out-rps-abs
net spindle-vel-cmd-rpm        <=  spindle.0.speed-out
net spindle-vel-cmd-rpm-abs    <=  spindle.0.speed-out-abs
net spindle-enable             <=  spindle.0.on
net spindle-cw                 <=  spindle.0.forward
net spindle-ccw                <=  spindle.0.reverse
net spindle-brake              <=  spindle.0.brake
net spindle-revs               =>  spindle.0.revs
net spindle-at-speed           =>  spindle.0.at-speed
net spindle-vel-fb-rps         =>  spindle.0.speed-in
net spindle-index-enable      <=>  spindle.0.index-enable

# ---Setup spindle at speed signals---

sets spindle-at-speed true

#  Use ACTUAL spindle velocity from spindle encoder
#  spindle-velocity bounces around so we filter it with lowpass
#  spindle-velocity is signed so we use absolute component to remove sign
#  ACTUAL velocity is in RPS not RPM so we scale it.

setp     scale.spindle.gain 60
setp     lowpass.spindle.gain 1.000000
net spindle-vel-fb-rps        =>     scale.spindle.in
net spindle-fb-rpm               scale.spindle.out       =>   abs.spindle.in
net spindle-fb-rpm-abs           abs.spindle.out         =>   lowpass.spindle.in
net spindle-fb-rpm-abs-filtered  lowpass.spindle.out  

#******************************
# connect miscellaneous signals
#******************************

#  ---HALUI signals---

net axis-select-x  halui.axis.x.select
net jog-x-pos      halui.axis.x.plus
net jog-x-neg      halui.axis.x.minus
net jog-x-analog   halui.axis.x.analog
net x-is-homed     halui.joint.0.is-homed
net axis-select-y  halui.axis.y.select
net jog-y-pos      halui.axis.y.plus
net jog-y-neg      halui.axis.y.minus
net jog-y-analog   halui.axis.y.analog
net y-is-homed     halui.joint.1.is-homed
net axis-select-z  halui.axis.z.select
net jog-z-pos      halui.axis.z.plus
net jog-z-neg      halui.axis.z.minus
net jog-z-analog   halui.axis.z.analog
net z-is-homed     halui.joint.2.is-homed
net jog-selected-pos      halui.axis.selected.plus
net jog-selected-neg      halui.axis.selected.minus
net spindle-manual-cw     halui.spindle.0.forward
net spindle-manual-ccw    halui.spindle.0.reverse
net spindle-manual-stop   halui.spindle.0.stop
net machine-is-on         halui.machine.is-on
net jog-speed             halui.axis.jog-speed
net MDI-mode              halui.mode.is-mdi

#  ---coolant signals---

net coolant-mist      <=  iocontrol.0.coolant-mist
net coolant-flood     <=  iocontrol.0.coolant-flood

#  ---probe signal---

net probe-in     =>  motion.probe-input

#  ---motion control signals---

net in-position               <=  motion.in-position
net machine-is-enabled        <=  motion.motion-enabled

#  ---digital in / out signals---

net dout-00     <=  motion.digital-out-00
net dout-02     <=  motion.digital-out-02
#  ---estop signals---

net estop-out     <=  iocontrol.0.user-enable-out
net estop-out     =>  iocontrol.0.emc-enable-in

#  ---manual tool change signals---

loadusr -W hal_manualtoolchange
net tool-change-request     iocontrol.0.tool-change       =>  hal_manualtoolchange.change
net tool-change-confirmed   iocontrol.0.tool-changed      <=  hal_manualtoolchange.changed
net tool-number             iocontrol.0.tool-prep-number  =>  hal_manualtoolchange.number
net tool-prepare-loopback   iocontrol.0.tool-prepare      =>  iocontrol.0.tool-prepared

Here is the INI
# Generated by PNCconf at Sat Aug 29 14:43:44 2020
# Using LinuxCNC version:  UNAVAILABLE
# If you make changes to this file, they will be
# overwritten when you run PNCconf again

[EMC]
MACHINE = Skyfire
DEBUG = 0
VERSION = 1.1

[DISPLAY]
DISPLAY = axis
POSITION_OFFSET = RELATIVE
POSITION_FEEDBACK = ACTUAL
MAX_FEED_OVERRIDE = 2.000000
MAX_SPINDLE_OVERRIDE = 1.000000
MIN_SPINDLE_OVERRIDE = 0.500000
INTRO_GRAPHIC = linuxcnc.gif
INTRO_TIME = 5
PROGRAM_PREFIX = /home/cnc/linuxcnc/nc_files
PYVCP = pyvcp-panel.xml
INCREMENTS = 5mm 1mm .5mm .1mm .05mm .01mm .001mm
POSITION_FEEDBACK = ACTUAL
DEFAULT_LINEAR_VELOCITY = 6.000000
MAX_LINEAR_VELOCITY = 25.000000
MIN_LINEAR_VELOCITY = 0.500000
DEFAULT_ANGULAR_VELOCITY = 12.000000
MAX_ANGULAR_VELOCITY = 180.000000
MIN_ANGULAR_VELOCITY = 1.666667
EDITOR = gedit
GEOMETRY = xyz

[FILTER]
PROGRAM_EXTENSION = .png,.gif,.jpg Greyscale Depth Image
PROGRAM_EXTENSION = .py Python Script
png = image-to-gcode
gif = image-to-gcode
jpg = image-to-gcode
py = python

[TASK]
TASK = milltask
CYCLE_TIME = 0.010

[RS274NGC]
PARAMETER_FILE = linuxcnc.var

[EMCMOT]
EMCMOT = motmod
COMM_TIMEOUT = 1.0
SERVO_PERIOD = 1000000

[HMOT]
# **** This is for info only ****
CARD0=hm2_7i76.0

[HAL]
HALUI = halui
HALFILE = Skyfire.hal
HALFILE = custom.hal
POSTGUI_HALFILE = postgui_call_list.hal
SHUTDOWN = shutdown.hal

[HALUI]

[KINS]
JOINTS = 3
KINEMATICS = trivkins coordinates=XYZ

[TRAJ]
COORDINATES =  XYZ
LINEAR_UNITS = mm
ANGULAR_UNITS = degree
DEFAULT_LINEAR_VELOCITY = 2.50
MAX_LINEAR_VELOCITY = 25.00

[EMCIO]
EMCIO = io
CYCLE_TIME = 0.100
TOOL_TABLE = tool.tbl

#******************************************
[AXIS_X]
MAX_VELOCITY = 25.0
MAX_ACCELERATION = 750.0
MIN_LIMIT = -0.01
MAX_LIMIT = 200.0

[JOINT_0]
TYPE = LINEAR
HOME = 0.0
FERROR = 100.0
MIN_FERROR = 0.0
MAX_VELOCITY = 25.0
MAX_ACCELERATION = 750.0
# The values below should be 25% larger than MAX_VELOCITY and MAX_ACCELERATION
# If using BACKLASH compensation STEPGEN_MAXACCEL should be 100% larger.
STEPGEN_MAXVEL = 31.25
STEPGEN_MAXACCEL = 937.50
P = 1000.0
I = 0.0
D = 0.0
FF0 = 0.0
FF1 = 1.0
FF2 = 0.0
BIAS = 0.0
DEADBAND = 0.0
MAX_OUTPUT = 0.0
ENCODER_SCALE = 2000.0
# these are in nanoseconds
DIRSETUP   = 10000
DIRHOLD    = 10000
STEPLEN    = 5000
STEPSPACE  = 5000
STEP_SCALE = 1000.0
MIN_LIMIT = -0.01
MAX_LIMIT = 200.0
HOME_OFFSET = 0.000000
HOME_SEARCH_VEL = -1.000000
HOME_LATCH_VEL = -0.500000
HOME_FINAL_VEL = 0.000000
HOME_USE_INDEX = NO
#******************************************

#******************************************
[AXIS_Y]
MAX_VELOCITY = 25.0
MAX_ACCELERATION = 750.0
MIN_LIMIT = -0.01
MAX_LIMIT = 200.0

[JOINT_1]
TYPE = LINEAR
HOME = 0.0
FERROR = 10.0
MIN_FERROR = 1.0
MAX_VELOCITY = 25.0
MAX_ACCELERATION = 750.0
# The values below should be 25% larger than MAX_VELOCITY and MAX_ACCELERATION
# If using BACKLASH compensation STEPGEN_MAXACCEL should be 100% larger.
STEPGEN_MAXVEL = 31.25
STEPGEN_MAXACCEL = 937.50
P = 1000.0
I = 0.0
D = 0.0
FF0 = 0.0
FF1 = 1.0
FF2 = 0.0
BIAS = 0.0
DEADBAND = 0.0
MAX_OUTPUT = 0.0
ENCODER_SCALE = 4000.0
# these are in nanoseconds
DIRSETUP   = 10000
DIRHOLD    = 10000
STEPLEN    = 5000
STEPSPACE  = 5000
STEP_SCALE = 200.0
MIN_LIMIT = -0.01
MAX_LIMIT = 200.0
HOME_OFFSET = 0.0
#******************************************

#******************************************
[AXIS_Z]
MAX_VELOCITY = 25.0
MAX_ACCELERATION = 750.0
MIN_LIMIT = -100.0
MAX_LIMIT = 0.01

[JOINT_2]
TYPE = LINEAR
HOME = 0.0
FERROR = 10.0
MIN_FERROR = 1.0
MAX_VELOCITY = 25.0
MAX_ACCELERATION = 750.0
# The values below should be 25% larger than MAX_VELOCITY and MAX_ACCELERATION
# If using BACKLASH compensation STEPGEN_MAXACCEL should be 100% larger.
STEPGEN_MAXVEL = 31.25
STEPGEN_MAXACCEL = 937.50
P = 1000.0
I = 0.0
D = 0.0
FF0 = 0.0
FF1 = 1.0
FF2 = 0.0
BIAS = 0.0
DEADBAND = 0.0
MAX_OUTPUT = 0.0
ENCODER_SCALE = 4000.0
# these are in nanoseconds
DIRSETUP   = 10000
DIRHOLD    = 10000
STEPLEN    = 5000
STEPSPACE  = 5000
STEP_SCALE = 200.0
MIN_LIMIT = -100.0
MAX_LIMIT = 0.01
HOME_OFFSET = 0.0
#******************************************

[SPINDLE_0]
MAX_VELOCITY = 150.0
MAX_ACCELERATION = 300.0
# The values below should be 25% larger than MAX_VELOCITY and MAX_ACCELERATION
# If using BACKLASH compensation STEPGEN_MAXACCEL should be 100% larger.
STEPGEN_MAXVEL = 187.50
STEPGEN_MAXACCEL = 375.00
P = 0.0
I = 0.0
D = 0.0
FF0 = 1.0
FF1 = 0.0
FF2 = 0.0
BIAS = 0.0
DEADBAND = 0.0
MAX_OUTPUT = 2000.0
ENCODER_SCALE = 4096.0
# these are in nanoseconds
DIRSETUP   = 10000
DIRHOLD    = 10000
STEPLEN    = 5000
STEPSPACE  = 5000
STEP_SCALE = 1024.0

Attached are pictures of the histogram and scope

as always thanks in advance for any suggestions on what to tinker with
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Last edit: 29 Aug 2020 22:23 by jhandel.

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29 Aug 2020 22:36 #179981 by tommylight

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29 Aug 2020 23:54 #179984 by PCW
Set all the P terms to about 5 to start

Delete all the "setp pid.N.maxerror .0005" statements

Expect runaways as it looks like you have the feedback reversed
If you get runaways, reverse the sign of STEP_SCALE

Then try tommylight's tuning suggestions

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30 Aug 2020 01:16 - 30 Aug 2020 01:18 #179990 by jhandel
PCW, yes I had it backwards... (well I had it to spec, but that meant the servo went backwards.. Easy flip in the Hal... Thanks for the max error & starting at P = 5..

I also copied over my max rapid and max acceloration from the old controller (10000mm/m & 600mm/s^2)

Those didn't help sadly... I also got a new error because I guess it maxes out the pulse count/speed is maxed out hm2_7i76e.0:stepgen.00.maxvel is to slow for the current step timing & position scale..... clipping to max possible.

And still getting joint failures..

I also got two new quarks
1 ) I can move with rarely a joint failure, going - joint failures all the damn time..
2) sometimes at the end of a move it will spend 10 seconds or so moving just the tiniest bit back and forth or crawling in one direction (the crawling is usually when it errors, the hunting is usually when I stop the jog on my own)
Last edit: 30 Aug 2020 01:18 by jhandel.

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30 Aug 2020 01:24 - 30 Aug 2020 01:25 #179991 by PCW
Joint following errors are pretty much expected until you get the tuning right
They may also be caused by drive setup (filtering or acceleration limits in the drive itself)

To eliminate the velocity limit you will have to lower the step time and step space
parameters

Crawling in one direction suggests you have a problem with the encoder feedback
Last edit: 30 Aug 2020 01:25 by PCW.

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31 Aug 2020 11:43 #180151 by jhandel
I wouldn't say crawling in one direction... More like hunting or settling.. Sometimes it stops on a dime, sometimes it sits there and vibrates back and forth a few microns (yes microns) sometimes it crawls a few 10ths of a mm in one direction before settling..

The hunting behavior back and forth can happen anytime I stop a jog, the crawl to a settle happens only with a joint error..

Neither are consistent behaviors

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31 Aug 2020 11:56 #180153 by PCW
Where is the encoder feedback coming from?

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31 Aug 2020 13:29 #180159 by jhandel
Encoder -> Servo Drive/Controller -> 7i89 -> 7i76e.P2 -> LinuxCNC (ethernet connection)

Same servo drive/servo ran the axis fine with no hunting behavior. So I think the behaviors are coming from LinuxCNC..

To be clear, the Servo Controller uses Step/Direction pulses.. But its an AC servo so really its all just "math" that the controller manages it actually uses the encoder steps/rotation and a "gear ratio" setting to define your desired steps/rotation.

I left it at 5000/rotation because that was what it was set-at with the old controller and with 5mm ball-screws it means its easy math 1 pulse/micron

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31 Aug 2020 13:37 #180160 by PCW
I asked about the the feedback source because linear scale systems often
have issues with hunting because of backlash

You might try open loop, since that is likely what you were doing before.
This just means changing the feedback from the encoders to the stepgen
position feedback pin (you would also set the P term back to 1000 in this case)

With LinuxCNC setup for open loop you can now use the encoder feedback
to see how well the drives actually follow the step/dir commands

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01 Sep 2020 01:13 - 01 Sep 2020 01:15 #180247 by jhandel
Converting to open does make a lot of since, I tried that and yah things move fine (which makes since because there is no feedback to adjust for..) I am guessing that getting close loop to work is a little crazy given there is a controller doing its own "PID" like control on the servo.. which means the two would end up "fighting" each other..

Now that the servo was moving pretty well, it gave me time to mess with the encoder weirdness you suggested. Sure enough halscope did display your suspected issue with encoder and going backwards (comparing commanded location to encoder location...

its clear that the encoder is not counting backwards correctly when I go in the -- direction..

Any ideas why an encoder would count perfect and consistently one direction but not the other?

All the same pulses should be going off in both directions right?
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Last edit: 01 Sep 2020 01:15 by jhandel.

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