Machsupport Forum

Mach Discussion => Mach4 General Discussion => Topic started by: wgpeters on May 09, 2018, 08:59:53 AM

Title: Mach4/Uc100 problem with jogging
Post by: wgpeters on May 09, 2018, 08:59:53 AM
My setup is Win10 HP Laptop, Mach4 Hobby, UC100, Vista Pendant,Sherline Lathe, Sherline Nexgen Mill

System does not jog correctly when backlash setting is non-zero in Mach.  This affects all axis.

Backlash adjustment is applied after each jog even though direction has not changed.  Sometimes, the stepper goes the wrong direction, and often the jog amount is wrong.  For instance a .01 jog may go .01, or may go something less.  This happens whether the jog was done from the pc jog button, or the pendant, so I believe the pendant is not the problem.

Smaller jog increments result in more erratic behavior, especially when the jog amount is less than the backlash setting (which in my case is set to .003".

When making successive jogs of .001, the movement is often .001, 0, .002, 0, .002, etc. 
When stepping by multiple gcodes, like g0 z .001, g0 z .002, g0 z .003 ..... the system seems to work correctly as shown by test indicator and visual observation.

UC100 is set to 25khz, but testing with 100khz had the same result.

Backlash should only be applied when changing directions.

System works correctly when driven by LinuxCNC so problem is not stepper malfunctions or the Sherline motor drivers.

Any ideas?




Title: Re: Mach4/Uc100 problem with jogging
Post by: joeaverage on May 09, 2018, 09:17:01 AM
Hi,
I wasn't aware that the UC100 supported backlash. Backlash compensation is a controller enacted feature, not really Mach at all.

Craig
Title: Re: Mach4/Uc100 problem with jogging
Post by: wgpeters on May 09, 2018, 09:31:48 AM
Yes, it is advertised to support backlash compensation.  If it doesn't, I just wasted $300
Title: Re: Mach4/Uc100 problem with jogging
Post by: ger21 on May 09, 2018, 09:41:22 AM
Send an email to CNC Drive and ask them about it. They're the only ones that will be able to answer this.
Title: Re: Mach4/Uc100 problem with jogging
Post by: joeaverage on May 09, 2018, 09:45:50 AM
Hi,
yes I agree with ger21, I can certainly find that the UC100 supports backlash compensation with Mach3 but cannot find anything
specific about Mach4.

Given that the UC100 Mach4 plugin is so new, probably less than a year, it would not surprise me that its not yet available.

Craig
Title: Re: Mach4/Uc100 problem with jogging
Post by: ger21 on May 09, 2018, 09:49:33 AM
Quote
Yes, it is advertised to support backlash compensation.

Where? I've never seen a list of supported Mach4 functions for any of CNC Drives motion controllers.
Title: Re: Mach4/Uc100 problem with jogging
Post by: wgpeters on May 09, 2018, 09:52:46 AM
https://cnc4pc.com/uc100-usb-motion-controller.html

At top of page, it says it supports Mach4
Near bottom, it says it supports backlash compensation.

It certainly implies that it should work.
Title: Re: Mach4/Uc100 problem with jogging
Post by: ger21 on May 09, 2018, 09:58:29 AM
No, it doesn't imply that it should work.
It's listed under "Supported Mach3 functions".
Title: Re: Mach4/Uc100 problem with jogging
Post by: joeaverage on May 09, 2018, 10:24:55 AM
Hi,
yes I also interpreted that as a supported Mach3 function not necessarily Mach4.

Craig
Title: Re: Mach4/Uc100 problem with jogging
Post by: wgpeters on May 09, 2018, 10:39:16 AM
Well then why does it say it now supports Mach 4.
It does not say it partially supports Mach 4 or that it supports Mach 4 with exceptions.



Title: Re: Mach4/Uc100 problem with jogging
Post by: ger21 on May 09, 2018, 10:42:16 AM
By supports Mach4, it means it has a Mach4 plugin.

Most Mach4 motion controllers only partially support Mach4. Meaning they don't support all of Mach4's features.
Title: Re: Mach4/Uc100 problem with jogging
Post by: joeaverage on May 09, 2018, 10:42:45 AM
Hi,
a quick email to CNCDrive will clear it up.

Craig
Title: Re: Mach4/Uc100 problem with jogging
Post by: wgpeters on May 09, 2018, 11:19:08 AM
I have sent an email to them.
Days ago I also posted the same information on their support forum, but so far, they haven't bothered to release my post.