recovering from a on limit error?
05 Jun 2015 20:26 #59474
by rotccapt
recovering from a on limit error? was created by rotccapt
hi all i have a couple odd questions. so i have my machine set up with individual limit loops for each axis, (XYZ) each has a combined home/min limit switch and max limit switch in the loop. my machine runs fine all travels are the right direction and it jogs in the right direction except after a limit trip on the y axis. if i accidentally jog into or hit the hard limit switch it will not allow me to jog off the switch even with the override limits box is clicked. It tells me "cant jog past hard limit"
my machine is a gantry router, home is at the forward left corner. the machine homes in the right direction but i had to make the home search and latch negative to get it to home correctly otherwise it would march off away from the home switch. also i can jog all the way to the y home/limit switch and trip it without hitting the soft limit. when i hit the y home switch it triggers a "on limit error" as expected then i hit the override limits and try to jog away but it will only allow jogging in the same direction as the switch.
also after homing my z axis, which i have set to the top of the machine, my DRO reads a positive 3" instead of zero like i think it should read. if i "touch off" the z axis everything reads correctly and jogging down to the table is negative and away from the table is positive
my machine is a gantry router, home is at the forward left corner. the machine homes in the right direction but i had to make the home search and latch negative to get it to home correctly otherwise it would march off away from the home switch. also i can jog all the way to the y home/limit switch and trip it without hitting the soft limit. when i hit the y home switch it triggers a "on limit error" as expected then i hit the override limits and try to jog away but it will only allow jogging in the same direction as the switch.
also after homing my z axis, which i have set to the top of the machine, my DRO reads a positive 3" instead of zero like i think it should read. if i "touch off" the z axis everything reads correctly and jogging down to the table is negative and away from the table is positive
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05 Jun 2015 21:13 #59479
by BigJohnT
Replied by BigJohnT on topic recovering from a on limit error?
The first thing is you don't have your travels setup correctly in your ini file, if you did you could not jog into the limit.
Do you have a G54 or any other offset in effect?
linuxcnc.org/docs/html/common/User_Conce...hen_you_8217_re_lost
JT
Do you have a G54 or any other offset in effect?
linuxcnc.org/docs/html/common/User_Conce...hen_you_8217_re_lost
JT
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06 Jun 2015 01:51 - 06 Jun 2015 02:18 #59497
by rotccapt
Replied by rotccapt on topic recovering from a on limit error?
i will take a good look at my ini file and check back later
i dont believe i have any offsets being used
i dont believe i have any offsets being used
Last edit: 06 Jun 2015 02:18 by rotccapt.
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06 Jun 2015 03:11 #59499
by BigJohnT
Replied by BigJohnT on topic recovering from a on limit error?
After you home if you have no offsets you should have all 0.0000's on the DRO.
JT
JT
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06 Jun 2015 04:14 #59500
by rotccapt
Replied by rotccapt on topic recovering from a on limit error?
so i decided to run step config again and i think i found my Y axis travel issue, i had my home switch set to 0 but my max table travel was set to -0.5. i have now set that to 0. after re homing the machine my DRO reads x -0.00, y 0.0837, z 2.2237 should i run the commands you linked earlyer?
here are my hal files and ini files
here are my hal files and ini files
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06 Jun 2015 18:24 #59512
by BigJohnT
Replied by BigJohnT on topic recovering from a on limit error?
Your ini file looks normal. After homing look on the DRO tab and everything should be 0.000 if not then you have an offset set. Follow the instructions in "When your lost" to remove any offsets.
JT
JT
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07 Jun 2015 00:22 #59538
by rotccapt
Replied by rotccapt on topic recovering from a on limit error?
thank you for your help ill give it a try and see what hapens
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07 Jun 2015 03:24 - 07 Jun 2015 03:24 #59550
by rotccapt
Replied by rotccapt on topic recovering from a on limit error?
thank you for helping me get my DRO working correctly i did have a g54 offset, not quite sure how that happened but that issue is resolved.
i still have my jogging off a limit issues. and now a little homing issue.
so after clearing the g54 offset and re homing my machine i get x 0.125 y 0.125 and z 0.00, so i went back to my ini file and changed the home to read 0.00 and changed my home offset to .125 (which is how far i want the machine to back off the home switch) when i home the machine the x axis travels the right direction hits the home switch backs off and then tries to drive through the home switch for its offset, i then switched the home offset to -0.125 and home works correctly but i get a "exceeded negative soft limit" error and the home sequence stops. i had to do the same thing with the y axis except when i manually home the y axis everything works as advertised with no limit errors. after clearing the x limit error the machine works fine and after adjusting my actual table limits i no longer jog into a hard limit.
now i still have my original problem of, if i manually trigger the min limit switch on both x and y and after toggling the override limits both axis will only jog in the direction of the switch, if i trigger the max limit both axis will move in the correct direction to jog off the switch
the only other bit of information i think might be causing some of my issues is that in order to get the x axis to move in the correct direction i had to invert the step and direction pins.
thank you again for your help with getting my machine to behave correctly
i still have my jogging off a limit issues. and now a little homing issue.
so after clearing the g54 offset and re homing my machine i get x 0.125 y 0.125 and z 0.00, so i went back to my ini file and changed the home to read 0.00 and changed my home offset to .125 (which is how far i want the machine to back off the home switch) when i home the machine the x axis travels the right direction hits the home switch backs off and then tries to drive through the home switch for its offset, i then switched the home offset to -0.125 and home works correctly but i get a "exceeded negative soft limit" error and the home sequence stops. i had to do the same thing with the y axis except when i manually home the y axis everything works as advertised with no limit errors. after clearing the x limit error the machine works fine and after adjusting my actual table limits i no longer jog into a hard limit.
now i still have my original problem of, if i manually trigger the min limit switch on both x and y and after toggling the override limits both axis will only jog in the direction of the switch, if i trigger the max limit both axis will move in the correct direction to jog off the switch
the only other bit of information i think might be causing some of my issues is that in order to get the x axis to move in the correct direction i had to invert the step and direction pins.
thank you again for your help with getting my machine to behave correctly
Last edit: 07 Jun 2015 03:24 by rotccapt.
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07 Jun 2015 06:56 #59552
by rotccapt
Replied by rotccapt on topic recovering from a on limit error?
well i think i got it all working thanks for the help, it donned on me a little bit ago that by inverting the x step and direction pins the axis went the right way but the linuxcnc though the axis was at the other end of the table. so i set the pins back to normal and made my axis scaling negative. i still needed to make my home position negative as well. now the machine homes correctly and i can jog all the way in any direction and only hit soft limits. I am not too concerned about the backing off the limit issue since if i hit a hard limit something went wrong anyways and i can just turn off the machine power and manually back the axis off and re home and start over.
again thank you for the help
again thank you for the help
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07 Jun 2015 19:36 #59571
by BigJohnT
Replied by BigJohnT on topic recovering from a on limit error?
If you can only jog toward the limit switch this means you have two limit switches for the axis and you have them connected up backwards. IE. min limit connected to max limit switch. This can be changed in your HAL file.
JT
JT
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