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slave axis aleatory movement
« on: August 14, 2015, 05:47:48 AM »
Hi Guys a newbie question!?

Mach3 in windows XP, X+A axis together in (config->slave axis).
When using arrow keys they are responsive but, one of the axis run OK, the other goes aleatory in both directions.
And in MPG mode when adjusting "slow jog rate" less than 50% the motor in case just shake..


Anyone could help me in this situation, please?

regards,
Marcelo

Offline Davek0974

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Re: slave axis aleatory movement
« Reply #1 on: August 14, 2015, 10:27:15 AM »
Are the motors/drives identical and setup with the identical values in motor tuning??
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.
Re: slave axis aleatory movement
« Reply #2 on: August 15, 2015, 10:49:27 PM »
Hi Dave,

Thanks for your answer,
yes, both motors are identical, and configuration looks the same..(attached are the x+a axis configuration)


I used this manual to configure it http://www.omc-stepperonline.com/download/pdf/4_Axis_TB6600_CNC_Driver_Board_Users_Manual.pdf
and to get values I used this http://prusaprinters.org/calculator/ 1.8 step angle, 1/2 uStepping, belt 2mm gt2 and 20 pulley tooth count (gives me the value 10)
9000 mm/min -> 150mm/s for max speed and 3000 mm/sec^2 as acceleration could be a little fast I really dont know (1/3G)??
I am using nema 23 motors 2.6A configures in the controller. the machine is a shapeoko alike.

Any help/suggestion is appretiated
Re: slave axis aleatory movement
« Reply #3 on: August 16, 2015, 12:34:09 AM »
Hi. You can try to use a different output on your TB-controller. f.x. use the Z-axis output for testing.
Fx. Switching A - Z axis. Testing if all the TB outputs are working correct.

Further I would go for 1/16 microstepping giving 80steps/unit , and a low acceleration to begin with, perhaps 0,05g
Also try to set the DIR timing to 5us, as you did with the Step.

Else triple check wiring again, and settings again.

Offline Davek0974

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Re: slave axis aleatory movement
« Reply #4 on: August 16, 2015, 03:01:38 AM »
For acceleration i would start with 1/10 of the max velocity so if your max velocity is 150 then set acceleration to 15 then work up.
 Never used the TB6600 board only the separate Leadshine style drives which seem much more robust.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.
Re: slave axis aleatory movement
« Reply #5 on: August 16, 2015, 11:12:50 AM »
Hi Guys,

Thanks again.

I will try tomorrow, and post the results here.

I will configure the board to 1/16 uStepping, using 80 in "steps per"(prusa calculator) field, keep velocity to 150 mm/s, acc to 0.05G and test DIR PULSE timming to 0 thru 5.

and also with previous configuration keeping velocity and changing acc to 0.015G (10% velocity)

Searching for https://www.google.com/search?q=mach3+motor+tuning&tbm=isch&tbo=u&source=univ&sa=X We are able to see a wide range of values in acc...

I am right now reading more about the Step/Dir pulse, and almost all reading goes to the delay associated to the optocouplers when switching.

Those settings could also be associated with wire length differences when, for example in slave mode?

1-2 meters difference between X/A could produce the previous effect?

regards,
« Last Edit: August 16, 2015, 11:16:43 AM by mvcorrea »

Offline Davek0974

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Re: slave axis aleatory movement
« Reply #6 on: August 16, 2015, 11:46:45 AM »
No point in setting pulse duration to zero, minimum is about 2us, average is 5us.

You say speed is 150mm/s thats 9000mm/min so i would start with acceleration of 900mm/s/s

You will find many different settings for speed and acceleration, that is because these values are specific to every machine, no averages or normal settings here.

Forget wire length, unless you have kilometres of it, its negligible.

Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.
Re: slave axis aleatory movement
« Reply #7 on: August 18, 2015, 10:37:47 PM »
Davek0974, fabhund, thanks for your help.

The problem: X+A axis in slave mode X works OK A works in aleatory directions.

The conclusion. I have a failing stepper motor.
First I swapped X and A and the problem stays in that motor(could only be the cable or stepper).
Reused Z axis in A and everything started working properly.
I let the controller(ebay TB6600 4 axis) to be in 1/16 uStepping and used this configurations in motor tuning (for reference).

Steps per: 80
velocity: 9000mm/min -> 150mm/s
acceleration: tweaked to let around 0.015G
let step: 5 and dir: 0 as it was previously.


« Last Edit: August 18, 2015, 10:41:25 PM by mvcorrea »