Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: justCNCit on July 10, 2017, 11:11:36 PM
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Hello, some more detail: I have disabled "home slave with master" in General Config. A home switch has been installed for the Y and A axis. But when hitting the REF button in diagnostics for Y, only the Y axis moves home, and the position for the A axis does not change even if I attempt to change that position manually. A and Y move together under ordinary operation fine. But A axis will not home at same time as Y. Thanks
Shawn
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here is the manual
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Thanks. I had used the diagnostics screen to REF Y but will try next to REF ALL. The A axis is not showing a position or movement on the Diagnostics screen regardless, so that isn't helpful, since if the two axis aren't assured to move together, you can wreck your gantry very fast. Will disconnect the steppers mechanically to test and report back.
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Ok I tried and it worked, but it was not helpful that A axis does not show a position on Diagnostics.
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why do you need to know the position of the A axis?
once both y & a are homed, they will have the same position
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if A was off, you would know by watching this number during homing?
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so here is how it works, both axis' move towards home.
Let's assume the a axis is further from home than the y axis.
the y axis with touch the y-homing switch and stop, while the a axis keeps moving towards the a-homing switch. Once the a-axis touches the a-homing switch, both axis are homed/even...now together they back off the homing switch
make sense?
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Yes. I just thought it might be informative to know if the A had been off for some reason. And I understand that Mach zeroes the axis once the home switch turns on and then off, so then the A switch must be positioned to turn on and off before fixed into place after the gantry has been stopped on the Y.
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if A was off, you would know by watching this number during homing?
Mach3 wouldn't know if it was off. Both numbers would be the same before homing, and after.
The only way to know if it's off, is if one side hits the switch before the other.
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So at this point hardware and software are sort of working.
A axis is not homing correctly. Y axis which is the master, homes very well. A axis comes back and will land anywhere within +/-0.020" and this defies my explanation. Diagnostic screens show home switch triggered just like the Y axis but the motors are not moving properly. I am thinking about writing software to handle the parallel port manually, based on the input pin and step output to the motor to position the motor square to its master.
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Just FYI, got tired of dealing with Mach 3 and installed an Arduino between the parallel port and the 540, with a homing program connected to the switches and it works perfectly now. I can post the program if people want to see, lessons learned here were that Mach does control direction outputs and override the Arduino even if there is no movement, so you would either have to disable those outputs from Mach in software or disconnect the cable while using the Arduino homing program. A $10 solution.