easy question on homing direction change (RESOLVED)

[tomj]

Newbie to centroid new machine setup with all in one. All is well but I'm homing the wrong direction in x and y. Is it correct that all I need to do is swap the numbers in the home + and - columns for those axes on the motor revs/inch page? The hom file does not indicate + or - so I guess that is built into that page?

[aamir]

For changing the home direction u need to edit cncm.hom file
M92/X Move to X+ve limit switch while
M91/X Move to X-ve limit switch

M26/X zero home position.
You can change the direction by M92/X

By default x-axis home is in -ve direction (M91/X)

[tomj]

got it, m92 is move to + home, m91 move to - home
thanks
tom

[cncsnw]

Assuming everything was set up correctly before, then when you change the homing direction, you will also need to change your software travel limits on the Machine Configuration -> Jog Parameters table.

For example, if you change an X axis from homing minus (M91) to homing plus (M92), then you would change the X axis plus travel distance to zero, and the minus distance to a negative number for the total travel of the axis.

[tomj]

Thanks, I was able to pass the system test by setting the dist between travel limits < distance between home switches. The installation manual implied that soft limits should only be set for the end of travel opposite the home end, is that correct? I'd like to have soft limits at the homing end as well if it won't interfere with homing. Is that possible?

[martyscncgarage]

Thanks, I was able to pass the system test by setting the dist between travel limits < distance between home switches. The installation manual implied that soft limits should only be set for the end of travel opposite the home end, is that correct? I'd like to have soft limits at the homing end as well if it won't interfere with homing. Is that possible?

NO it doesn't work that way.
When your machine homes, it hits the MECHANICAL switch, then come off of it and hunts for the Z index marker pulse for precise repeatable homing. That position is MACHINE 0. You set the SOFT limit for the other end of the travel, it must be shy a certain amount from the opposite end mechanical travel switch. The SYSTEM test checks all of this. SO, if you passed the system test your machine should be setup properly. Leave it alone. Make a back up of the report file on a USB stick and keep it tagged and perhaps in the control cabinet or somewhere safe. The control will make a frequent back up of the report file. BUT if the drive crashes, all your work is out the window and you'll have to start from scratch again. A new drive or computer, a fresh install of the software and restoring from a report will have you back up and running in minutes.

Marty

[tomj]

I know about the report, but during jogging or running a program is there a way to have the machine decel prior to touching the limit switch at the home end of travel like (I think it supposed to) at the far end? I think I read that it will error out if a program is loaded that commands a move outside of the travel limits (or soft limits if configured). Presumably the control could be configured to know to suspend a programmed soft limit for the homing end only when actually homing, no? or maybe it already knows to decel a certain distance from that switch?

[martyscncgarage]

I know about the report, but during jogging or running a program is there a way to have the machine decel prior to touching the limit switch at the home end of travel like (I think it supposed to) at the far end? I think I read that it will error out if a program is loaded that commands a move outside of the travel limits (or soft limits if configured). Presumably the control could be configured to know to suspend a programmed soft limit for the homing end only when actually homing, no? or maybe it already knows to decel a certain distance from that switch?

If you set up the soft limits correctly, the control does this automatically as it approaches the soft limits.
This is part of the system test. To make sure YOU configured all of this correctly

[tomj]

I see, so that was the multiple triggers of the limit switches during the system test. So I can assume that the system will decelerate as it approaches BOTH the limit switches used for homing as well as the opposite end ones that I have entered soft limit numbers for even though I have zero in the soft limit column for the homing end of those axes?

[martyscncgarage]

I see, so that was the multiple triggers of the limit switches during the system test. So I can assume that the system will decelerate as it approaches BOTH the limit switches used for homing as well as the opposite end ones that I have entered soft limit numbers for even though I have zero in the soft limit column for the homing end of those axes?

Correct. 0 typical for the homing end.
If you passed systems test, you should be good to go provided axis are calibrated correctly.

Marty