Index Homing odd offset

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11 years 1 day ago #64553 by andypugh
Replied by andypugh on topic Index Homing odd offset

OT-CNC wrote: How does this come into play in the hal file? Should this be the same number as the FERROR?
setp pid.z.maxerror .0005


No, the pid error limits are all about controlling the way the pid works, mainly to prevent wind up.
The parameters are all described here:
www.linuxcnc.org/docs/html/man/man9/pid.9.html

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10 years 11 months ago #64758 by OT-CNC
Replied by OT-CNC on topic Index Homing odd offset
As far as this topic is concerned, homing with index does work as pointed out if the settings are right.
That part seems to work now for me.
Currently, I'm still having tuning issues. It does not seem to matter what I do, I can't see any clear progress. I'm re-attaching the ini file in case something is missing there.
Also, PCW how is progress on the custom 5i25 firmware for the SpinX? Thank you for your time.
Code:
# Generated by PNCconf at Wed Aug 19 18:14:48 2015 # If you make changes to this file, they will be # overwritten when you run PNCconf again [EMC] MACHINE = lathe_v6 DEBUG = 0 [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/ot/linuxcnc/nc_files PYVCP = pyvcp-panel.xml INCREMENTS = .1in .05in .01in .005in .001in .0005in .0001in LATHE = 1 DEFAULT_LINEAR_VELOCITY = 0.250000 MAX_LINEAR_VELOCITY = 5.000000 MIN_LINEAR_VELOCITY = 0.010000 DEFAULT_ANGULAR_VELOCITY = 0.250000 MAX_ANGULAR_VELOCITY = 1.000000 MIN_ANGULAR_VELOCITY = 0.010000 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 COMM_WAIT = 0.010 SERVO_PERIOD = 1000000 [HOSTMOT2] # **** This is for info only **** # DRIVER0=hm2_pci # BOARD0=5i25 [HAL] HALUI = halui HALFILE = lathe_v6.hal HALFILE = custom.hal POSTGUI_HALFILE = postgui_call_list.hal SHUTDOWN = shutdown.hal [HALUI] [TRAJ] AXES = 3 COORDINATES = X Z LINEAR_UNITS = inch ANGULAR_UNITS = degree CYCLE_TIME = 0.010 DEFAULT_VELOCITY = 0.10 MAX_LINEAR_VELOCITY = 5.0 [EMCIO] EMCIO = io CYCLE_TIME = 0.100 TOOL_TABLE = tool.tbl TOOL_CHANGE_WITH_SPINDLE_ON = 1 #******************** # Axis X #******************** [AXIS_0] TYPE = LINEAR HOME = 0.0 FERROR = 0.5 MIN_FERROR = 0.5 MAX_VELOCITY = 5.0 MAX_ACCELERATION = 30 # 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 = 6.0 STEPGEN_MAXACCEL = 37.50 P = 50.0 I = 0.0 D = 0.0 FF0 = 0.0 FF1 = 1.0 FF2 = 0.0 BIAS = 0.0 DEADBAND = 0.0 MAX_OUTPUT = 6.0 ENCODER_SCALE = 20000.0 # these are in nanoseconds DIRSETUP = 1000 DIRHOLD = 1000 STEPLEN = 1000 STEPSPACE = 1000 STEP_SCALE = 20000.0 MIN_LIMIT = -0.25 MAX_LIMIT = 12.0 HOME_OFFSET = 0.02500 HOME_SEARCH_VEL = 0.050000 HOME_LATCH_VEL = -0.030000 HOME_FINAL_VEL = 0.030000 HOME_USE_INDEX = YES HOME_SEQUENCE = 1 #******************** # Axis Z #******************** [AXIS_2] TYPE = LINEAR HOME = 0.0 FERROR = 0.5 MIN_FERROR = 0.5 MAX_VELOCITY = 5.0 MAX_ACCELERATION = 30 # 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 = 6.0 STEPGEN_MAXACCEL = 37.50 P = 50.0 I = 0.0 D = 0.0 FF0 = 0.0 FF1 = 1.0 FF2 = 0.0 BIAS = 0.0 DEADBAND = 0.0 MAX_OUTPUT = 6.0 ENCODER_SCALE = -20000.0 # these are in nanoseconds DIRSETUP = 1000 DIRHOLD = 1000 STEPLEN = 1000 STEPSPACE = 1000 STEP_SCALE = -20000.0 MIN_LIMIT = -10.000 MAX_LIMIT = 0.010 HOME_OFFSET =0.02500 HOME_SEARCH_VEL = 0.050000 HOME_LATCH_VEL = -0.030000 HOME_FINAL_VEL = 0.030000 HOME_USE_INDEX = YES HOME_SEQUENCE = 0 #******************** # Spindle #******************** [SPINDLE_9] P = 0 I = 0 D = 0 FF0 = 1 FF1 = 0 FF2 = 0 BIAS = 0 DEADBAND = 0 MAX_OUTPUT = 2000

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10 years 11 months ago #64759 by PCW
Replied by PCW on topic Index Homing odd offset
Note that tuning is partially done in your drive, any tuning issues there will become
apparent when you try and close the loop in LinuxCNC.

(If you run the drives open loop you might not ever notice the errors)

Tuning issues in the drive will not be fixable in LinuxCNC and must be fixed by tuning the drive

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10 years 11 months ago #64762 by OT-CNC
Replied by OT-CNC on topic Index Homing odd offset
That is a very good point. The dmm drives do come with a basic tuning program. I adjusted the pid settings there and ended up with something close to the default numbers. Too much P and the motor got noisy so I backed off. I have a very small amount of overshoot on the heavy Z, around .0005" to .001", always returns to 0 on the dial indicator. This is in stepper mode, slow feed or rapids, and I think that can be adjusted out in the drive pid loop or I can live with it.
In stepper mode, it feels responsive and I have not been able to fault out the drive itself.
In closed loop, it feels way off, more like some parameter is missing. Axis either creeps, dithers or is bouncing back and forth with frequency increasing at no external jogging command given. Axis jogs okay at 12-17 ipm or below, above that it joint following errors out. Direction change sometimes triggers error at slow speed.
If the drive remains powered up with no steps being sent, the motor stays at rest with no oscillations as expected.

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10 years 11 months ago #64763 by andypugh
Replied by andypugh on topic Index Homing odd offset
It would be interesting to see if the velocity scaling is correct.
With P = 0 do you see the encoder-velocity and the stepgen.velocity-command matching?

They should be pretty much exactly the same number without PID interfering.

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10 years 11 months ago #64764 by OT-CNC
Replied by OT-CNC on topic Index Homing odd offset
Andy,

I will try to capture that with halscope.

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