Backlash Compensation not affecting axis travel.

[EMartin]

Hi Folks,
I've been searching for a few hours on this forum looking for the problem I have, but none seem to work for me.

I have ~0.004" backlash in the z-axis, but after entering value and restarting Mach3, the milling machine does not respond to the compensation. The values are 'saved', and I have tried different Backlash Speeds, Shuttle Accelerations, axis, and even different compensation numbers.

I have an indicator setup, and step the axis in 0.001" increments, when reversing it takes 4-5 'steps' to register movement.  Also the machine is a retrofit, and with previous software I could here extra 'steps' the stepper would take as it reversed, but have not heard that noise, even when trying different compensations values on different axis.

Does the compensation only work when a toolpath is running?

Thanks for your help.
Eric

[bill-the-cat]

This may be too simple, but is the "Backlash Enabled" box checked?

[EMartin]

Ha, I was supposed to say "I tried both", which I did.  Yes, it is currently 'checked on'.

Also, My current settings:

z-axis: 0.004
all other axis: 0
Backlash Speed 20%
Backlash Enabled: checked
Shuttle Accel: 0.05 sec

Thanks.
Eric

[bill-the-cat]

I'm at a loss.  I just tried it on my machine (stepping at .001/step) and, when changing direction, my stepper jumps to take up the backlash amount I have set for the axis.

The only difference is my Backlash Speed is 75% and my Shuttle Accel is .02.

I do seem to remember problems with backlash in some older versions.  I'm using R3.042.020.  Which version are you using?

[EMartin]

Thanks for your help Bill.  I tried your speed/accel settings but that didn't do it.

Version: R3.042.040 (Ha, 'demo version'...still waiting for license file, or IRS, to come to me.)

I must say I saw a post that had a solution similar to mine, and was fixed.  Unfortunately the solution was a windows reinstall.  I'm hoping that is not the way to go.

[bill-the-cat]

Well, you've got me really curious now.  I'm having a hard time seeing how the Windows install could affect something as specific as backlash compensation and not manifest itself in other ways. Can you point me to the post you are referring to?

I don't know if it would be much less trouble for you than a Windows reinstall (or whether it would make any difference), but you could try downloading the older version of Mach that I'm using 3.042.020.  It's available via FTP.

[Hood]

It could be because its the deo, its not one of the features I know of that are disabled in demo but it could well be.
Hood

[bill-the-cat]

I hadn't even thought about that.  I've got a license, so that may be it.

I know about the 500 line limit, but is there a "list" somewhere outlining just what does and doesn't work in the demo version?

It would be a nice thing to have when testing with the demo version. Then a "potential customer" would know it's a demo issue rather than thinking it's a bug in the software.

[Hood]

Dont think there is a list but if you are up for it you could easily test, just remove your licence from the Mach folder and open Mach and test.

The things I do know of are
500 line limit in Mill and 100 in Turn (may be 150)
Run From Here doesnt work
Threading in Turn doesnt work.

I am sure there are a few others but I forget what they are.
Hood

[bill-the-cat]

Well, it's not the fact that it's a demo version.  I just moved my license file and the backlash compensation still worked.