Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: TFT on April 19, 2016, 04:58:46 PM

Title: Backlash correction not working?
Post by: TFT on April 19, 2016, 04:58:46 PM

If I move my x-axis forward three inches then back, it will be short by 0.02"

I entered 0.02 in the backlash setting for x-axis but is seems to make no difference at all what value I put there.

I saved by exiting the program and restarting.

Also, what does "enable backlash" check box mean on that setting page?

Thanks

Title: Re: Backlash correction not working?
Post by: Hood on April 19, 2016, 05:05:12 PM

Enable Backlash means Enable the Backlash Compensation. If you do not have that chosen then Backlash Comp will not be enabled and it will make no difference whether you have 0.02 or 2000 in the boxes above.

Hood

Title: Re: Backlash correction not working?
Post by: TFT on April 21, 2016, 12:37:51 PM

OK.  still doesn't seem to do anything. I'm going to keep playing with it.

Title: Re: Backlash correction not working?
Post by: robertspark on April 21, 2016, 01:16:44 PM

Are you using a motion controller or the parallel port.

If so which motion controller?

Title: Re: Backlash correction not working?
Post by: TFT on April 21, 2016, 01:46:46 PM

im using the parallel port

Title: Re: Backlash correction not working?
Post by: robertspark on April 21, 2016, 02:02:51 PM

It should work, your screen should look like the below sreenshot

Problems normally occur with motion controllers as the backlash compensation needs to be done within the plugin of the motion controller as its not a mach operation (hence it is done within the parallel port plugin directly).

Suggest trying version .062 and not .066 as it may solve your problem (worth a try....)
ftp://anonymous@machsupport.com/Mach3/

You'll need to add the colon ( : )after the "ftp" part for the link to work


Rob

Title: Re: Backlash correction not working?
Post by: RICH on April 22, 2016, 05:52:32 AM

As noted BC must be enabled  and also look at the following:

http://www.machsupport.com/forum/index.php/topic,29149.msg204717.html#msg204717

RICH

Title: Re: Backlash correction not working?
Post by: PW8697 on April 22, 2016, 10:36:30 AM

TFT,

Keep working at it and let us know how it goes.  I have a Taig mill and a while back I was working on trying to get rid of .003" in the Y.  I played with every setting, tried the 50/50/50 rule and never could get the backlash compensation to work, the motors always seemed to be loosing steps.  Max speed is only 25in/min.  Ultimately I just replaced the Y screw and nut.  So far it has been working fine.  BUT, I still want to get the backlash compensation to work for it will help as these nuts and screws wear.  It may also be my motion controller, I might have to try another.  I may go that route anyway because this one has a shift button issue where it will think the shift button is still depressed when it is not.  I am using a USB, Leafboy77 board.

I like the USB setup, and don't really want to mess with a parallel, unless they are plug and play as this one pretty nearly is.  Ethernet is also a possibility. 

Title: Re: Backlash correction not working?
Post by: TFT on April 22, 2016, 11:17:02 AM

Quote from: RICH on April 22, 2016, 05:52:32 AM

As noted BC must be enabled  and also look at the following:

http://www.machsupport.com/forum/index.php/topic,29149.msg204717.html#msg204717

RICH

Regarding that post, what is The Shuttle Wheel Accel?  Is that a specific setting or are you just referring to the acceleration of the motor you're trying to eliminate the backlash from?

Title: Re: Backlash correction not working?
Post by: robertspark on April 22, 2016, 01:56:48 PM

General Configuration Tab, top right hand side.

Title: Re: Backlash correction not working?
Post by: robertspark on April 22, 2016, 01:58:52 PM

Bottom of page two here:
http://www.machsupport.com/wp-content/uploads/2013/02/Mach3_CVSettings_v2.pdf