Stepconf works but Axis dont move - Speed Error

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11 years 1 month ago #63061 by Kolbi
Stepconf works but Axis dont move - Speed Error was created by Kolbi
Hi EMC-Fans,

Maybe somebody can help me with a Problem.

I built a belt driven Machine which drives 300mm/s with 2000 acceleration on XY without Problems, but when i increase the speed of the leadscrew Z-Axis above 12mm/s, all axes dont move anymore in Axis/Main Program.

In Stepconf Z works up to 20mm/s, this is slight above 20khz, this seems to be the max frequency of my stepper driver octocouplers. Step Pulses are 10000ns, Jitter 10000, gives me max 25khz step frequency from pc.

So it should work, but it doesnt, tried several things like inverting and changing pins, manual enable, increasing voltage for octocouplers to 6V (this solved the direction error on Y axis i had sometimes), etc...

Nothing seems to work, i think its some kind of limitation in the program i dont know.
If i reduce microstepping on Z, i can drive faster, but less torque and loosing steps. :S


Here my actual working config:

Z-Axis:

Steps: 400
Micro: 8
Transmission: 1:1
Leadscrew: 3mm
Max Speed: 12mm/s
Max Acc: 1000mm/s

Time to max Speed: 0.0120s
Distance to max Speed: 0.0720mm
Max Step Frequ.: 12800Hz
Steps/mm: 1066.7

It seems that 12mm/s = 12800Hz is the limitating factor, if i go above, nothing works anymore (except Stepconf), i hope somebody can help :(

Greetings from Austria, and sorry for my bad english :cheer:

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11 years 1 month ago #63074 by cncbasher
Replied by cncbasher on topic Stepconf works but Axis dont move - Speed Error
a few questions ?

what stepper drivers are you using ?
and what voltage is your power supply and current rating ?

the chance is your trying to run the steppers faster than they are capable in your velocity ratings , along with the incorrect step timings
Step Pulses are 10000ns, Jitter 10000 ( this at first glance is incorrect )

are you using a laptop ?
increasing voltage to drivers will damage the parallel port , at some stage so beware
are you connecting the positive of your opto to 5v and the neg side to the parrallel port ?
so sinking the current rather than sourcing , is far better

steps should be set at 200 not 400 , so check this
check your axis for any mechanical binding , on the leadscrew

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11 years 1 month ago #63075 by Kolbi
Replied by Kolbi on topic Stepconf works but Axis dont move - Speed Error
Why is 10000ns Jitter incorrect? Jitter Test shows about 8000 max Jitter.

400 Steps are correct, its a 0.9° Nema23. Hardware Setup is correct, everything works with 12mm/s Z-Speed.

I use a octocoupler Board, and can drive Z up to 21khz in Stepconfig, but why not in the Main Program?

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11 years 1 month ago #63081 by PCW
Replied by PCW on topic Stepconf works but Axis dont move - Speed Error
Are you using the stepgens reset feature?
if all three axis have 10 usec step pulse widths and you use the reset feature you are very close
to running out of time at 20 KHz step rate (since the CPU stalls for the entire pulse width and this could happen
on all three axis)

What base thread period are you using?

Your acceleration is pretty fast ( 12 ms to full speed ) might try lowering that

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11 years 1 month ago #63082 by Kolbi
Replied by Kolbi on topic Stepconf works but Axis dont move - Speed Error
I dont know what the stepgen reset feature is!?

I use the German GUI, is base thread period the number above Max Step Frequency? Then its 20000ns.

Reducing Acceleration did not work :(

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11 years 1 month ago #63084 by PCW
Replied by PCW on topic Stepconf works but Axis dont move - Speed Error
20000 ns is pretty fast

You might increasing the period to 30000 ns or so and see if that helps

It could be that you are just running out of I/O cycles, especially if this is a motherboard parallel port

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11 years 1 month ago #63086 by cncbasher
Replied by cncbasher on topic Stepconf works but Axis dont move - Speed Error
their are a number of reasons we as moderators ask questions that new members may think are not part of the problem,
to eliminate common problems .

have you changed the max velocity settings in your ini file , they are set by default at a low speed , by stepconf

perhaps you could archive your config and attach

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11 years 4 weeks ago #63363 by Kolbi
Replied by Kolbi on topic Stepconf works but Axis dont move - Speed Error
Thanks for the help so far, here is my config:

# Erstellt von stepconf am Mon Sep 28 21:23:52 2015
# Änderungen an dieser Datei werden beim nächsten
# Aufruf von stepconf überschrieben.
Code:
[EMC] MACHINE = Tsegi1 NML_FILE = emc.nml DEBUG = 0 [DISPLAY] DISPLAY = axis EDITOR = gedit POSITION_OFFSET = RELATIVE POSITION_FEEDBACK = ACTUAL MAX_FEED_OVERRIDE = 1.2 INTRO_GRAPHIC = emc2.gif INTRO_TIME = 5 PROGRAM_PREFIX = /home/cnc/emc2/nc_files INCREMENTS = 5mm 1mm .5mm .1mm .05mm .01mm .005mm [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 = emc.var [EMCMOT] EMCMOT = motmod COMM_TIMEOUT = 1.0 COMM_WAIT = 0.010 BASE_PERIOD = 36057 SERVO_PERIOD = 1000000 [HAL] HALFILE = Tsegi1.hal HALFILE = custom.hal POSTGUI_HALFILE = custom_postgui.hal [TRAJ] AXES = 3 COORDINATES = X Y Z LINEAR_UNITS = mm ANGULAR_UNITS = degree CYCLE_TIME = 0.010 DEFAULT_VELOCITY = 25.00 MAX_LINEAR_VELOCITY = 250.00 [EMCIO] EMCIO = io CYCLE_TIME = 0.100 TOOL_TABLE = tool.tbl [AXIS_0] TYPE = LINEAR HOME = 0.0 MAX_VELOCITY = 250.0 MAX_ACCELERATION = 2000.0 STEPGEN_MAXACCEL = 2500.0 SCALE = 32.0 FERROR = 1 MIN_FERROR = .25 MIN_LIMIT = -0.001 MAX_LIMIT = 710.0 HOME_OFFSET = -3.000000 HOME_SEARCH_VEL = -20.000000 HOME_LATCH_VEL = 15.625000 HOME_IGNORE_LIMITS = YES HOME_SEQUENCE = 1 [AXIS_1] TYPE = LINEAR HOME = 0.0 MAX_VELOCITY = 250.0 MAX_ACCELERATION = 2000.0 STEPGEN_MAXACCEL = 2500.0 SCALE = 39.2156862745 FERROR = 1 MIN_FERROR = .25 MIN_LIMIT = -0.001 MAX_LIMIT = 750.0 HOME_OFFSET = -3.000000 HOME_SEARCH_VEL = -20.000000 HOME_LATCH_VEL = 12.750000 HOME_IGNORE_LIMITS = YES HOME_SEQUENCE = 2 [AXIS_2] TYPE = LINEAR HOME = 80.0 MAX_VELOCITY = 12.3502371246 MAX_ACCELERATION = 1000.0 STEPGEN_MAXACCEL = 1250.0 SCALE = 1066.66666667 FERROR = 1 MIN_FERROR = .25 MIN_LIMIT = 0.0 MAX_LIMIT = 80.001 HOME_OFFSET = 83.000000 HOME_SEARCH_VEL = 5.000000 HOME_LATCH_VEL = -0.468750 HOME_IGNORE_LIMITS = YES HOME_SEQUENCE = 0

The Base Period is much higher than 10000, lowering it to 10000 did not work. Maybe you have some ideas what to do?

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11 years 3 weeks ago #63607 by Kolbi
Replied by Kolbi on topic Stepconf works but Axis dont move - Speed Error
Does anybody have an idea what i could try?

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11 years 3 weeks ago #63608 by cncbasher
Replied by cncbasher on topic Stepconf works but Axis dont move - Speed Error
This is incorrect :
If i reduce microstepping on Z, i can drive faster, but less torque and loosing steps

reducing microstepping will increase torq

ok please attach your full config as an archive to this post , and please give us this information

what stepperdrives you are using
what stepper motors ,
what voltage & current rating is your power supply
are you using ballscrews or threaded rod , and are they driven directly or via a belt drive

it seems you are driving the axis at a higher velocity than it is capable of , z axis shows this as missing steps , and always in the downward direction .
this also can be attributable to not having an adequate power suppy , under demand conditions

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