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Offline ks2

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soft limit issue
« on: December 05, 2012, 11:55:06 PM »
Hello
New here and I seem to have gotten everything under control with the exception of the soft limits. some details...
Ref all, is to the back right corner, I know i can reverse this in the settings to home at the right front, but makes no matter to me unless it is part of the prob.
x- homes in the positive
y- homes in the Negative
Z- homes (up) in the Positive
This is as read from the DRO.

Motor home/soft limits
X-SoftMax21.3/SoftMin0/SZone2"/AutoZero-Yes
Y-SoftMax22.4/SoftMin0/SZone2"/AutoZero-Yes
Z-SoftMax0/SoftMin-4/SZone1"/AutoZero-Yes

Machine operates normally with the "Ref all" operating all 6 switches (2 on each axis wired in series to one input)
and reading zero as one would expect.
Problem here is that when ever i press the "soft limits" button on the screen I get the "machine out of limits for soft limit activation"
I have read many threads and watched the mach 3 vid on the subject but I am not getting anywhere and have tried many variations based on diff threads.
The reason that I gave info on the homing direction is that when I was auto setting the switches for the limits I was not sure of the ++ and -- direction in relation to the machine (don't know if it makes any diff as all the switches are in series).
any thoughts would be appreciated

PS
under "ports/pins" i have X++ through Z Home enabled.
Thanks
Ken

Offline Hood

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Re: soft limit issue
« Reply #1 on: December 06, 2012, 03:07:05 AM »
What you really should do is have it so Mach sees the Home position as the cutter over the lower left of the table. From  your description it sounds like you are upper left. However your description is a bit confusing as you say back right but then say Y homes negative, that doesnt seem to tie in.
Ok so to start again, the X0Y0 convention is that your axis are fully negative whenat machine Zero, what that means is the cutter is sitting over the lower left of your work area (if looking from above) That however doesnt mean you have to physically home to that position, if it makes things easier for loading for example it can make more sense to home to Upper Left or even Upper Right. What you do in a situation like that is enter the distance that the axis is away from conventional Zero into the Home Off box.
So say your X is fully positive when homed, set the Home Off to the axis travel amount (21.3 in your case) and thus when you home the machine coords will be seen by Mach as that value and Mach will know the true machine zero is is 21.3 in the opposite direction.
If you do that then your soft limits will work fine.

You could of course just set a negative value for X Max in the soft limits but to me that is going against normal convention and could be confusing.

Hood

Offline ks2

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Re: soft limit issue
« Reply #2 on: December 06, 2012, 07:20:52 AM »
Hood
I apologize and of course you are correct, I meant to say the as looking from above, the machine homes to the upper left.  Having said that and from your comments, at least I know the axis's are running in the proper direction as I was concerned that when I auto set the limit switches in the setup that I may have effected travel direction due to my inability to determine pos or neg direction.
If I am understanding you correctly, it would not make any difference where on the machine I homed it, I just have to input the total travel distance from the HOME position to the end of my machines travel.
Lastly I am not sure where the input is located for the "HOME OFF" in the software, that may be the culprit for me.
Thanks
Ken

Offline Hood

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Re: soft limit issue
« Reply #3 on: December 06, 2012, 07:44:47 AM »
Ok just to confirm, as your tool moves right the X axis DRO increases (goes positive) and as your tool goes away from you the Y axis Increases?
If that is correct and you do home fully positive on both X and Y then you want to set the Home Off value of each to the amount of axis travel you have on the repective axis. The Home Off is on the Softlimits page.
Hood

Offline BR549

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Re: soft limit issue
« Reply #4 on: December 06, 2012, 12:40:13 PM »
IF your Machine home is top left then your work zone would be X+ and Y-  . You HAVE to set the soft zones to match that.

Just a thought, (;-)TP