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Author Topic: Mach 3 homing of master and slave axis, how to configure?  (Read 1678 times)

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Mach 3 homing of master and slave axis, how to configure?
« on: July 10, 2017, 11:11:36 PM »
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
Re: Mach 3 homing of master and slave axis, how to configure?
« Reply #1 on: July 11, 2017, 12:53:04 PM »
here is the manual
Re: Mach 3 homing of master and slave axis, how to configure?
« Reply #2 on: July 11, 2017, 12:59:20 PM »
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.
Re: Mach 3 homing of master and slave axis, how to configure?
« Reply #3 on: July 11, 2017, 01:20:44 PM »
Ok I tried and it worked, but it was not helpful that A axis does not show a position on Diagnostics.
Re: Mach 3 homing of master and slave axis, how to configure?
« Reply #4 on: July 11, 2017, 01:30:08 PM »
why do you need to know the position of the A axis?

once both y & a are homed, they will have the same position
Re: Mach 3 homing of master and slave axis, how to configure?
« Reply #5 on: July 11, 2017, 01:33:31 PM »
if A was off, you would know by watching this number during homing?
Re: Mach 3 homing of master and slave axis, how to configure?
« Reply #6 on: July 11, 2017, 01:46:13 PM »
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?
Re: Mach 3 homing of master and slave axis, how to configure?
« Reply #7 on: July 11, 2017, 01:59:45 PM »
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.

Offline ger21

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Re: Mach 3 homing of master and slave axis, how to configure?
« Reply #8 on: July 11, 2017, 03:25:43 PM »
Quote
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.
Gerry

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Re: Mach 3 homing of master and slave axis, how to configure?
« Reply #9 on: July 13, 2017, 01:08:21 AM »
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.