Author Topic: Appreciate some help with confusion over limit switch set up  (Read 1785 times)

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Offline Joz

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Appreciate some help with confusion over limit switch set up
« on: February 16, 2015, 04:35:10 PM »
Hi,

I've recently changed my CNC computer and installed a motion controller UC300-5LPT as well. I'm using a homemade gantry router type machine.
I have imported my .xml profile from my old computer but the CNC is not behaving as it did before.
When I try to do a "Ref all Home", the Z axis travels up to it's top limit switch, and then the Y axis starts, when it gets to it's limit switch, it over rides it and keeps going, like it doesn't notice that it has been triggered.
I can back off it with the jog button, and it travels rapidly away from the switch. Before it would travel slowly when it was at this point, and I would have to reset it again when the switch was un triggered.
I was sure this is a simple problem to do with active low/high settings so I have adjusted everything I can through trial and error but I can't seem to work it out.
I had to go through the settings when I fitted the motion controller and change them to port 2 instead of port 1, but apart from that I don't think I have changed anything from my original machine set up.
I only have a very basic grasp of what all the ports, inputs and output configurations in Mach3 are about as you can probably tell. 
I'm a bit stumped, can anyone help?  :)
Thanks
Joz

Offline Hood

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Re: Appreciate some help with confusion over limit switch set up
« Reply #1 on: February 18, 2015, 06:56:40 AM »
First thing to check is that the switches actually work as intended by watching the Home switch LEDs on the diagnostics page and press each one in turn, confirming they light as expected.

If they do then it may be something in the plugin config that needs set up correctly.

Hood

Offline Joz

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Re: Appreciate some help with confusion over limit switch set up
« Reply #2 on: February 19, 2015, 08:42:28 AM »
Hi Hood,
Yes the switches do work and the home switch LED's do light up on the diagnostics page when pressed.
I assume then that everything is ok with the Mach3 set up and it is more likely to be something in the plugin config that needs attention, i'll look into it in more detail
thanks

Offline Joz

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Re: Appreciate some help with confusion over limit switch set up
« Reply #3 on: February 19, 2015, 09:37:08 AM »
Ok worked it out, the X and Y homing/limit switches were on the wrong pins, so when doing an Ref all Home, the axis wouldn't stop moving when it hit the switch because the wrong switch was assigned to that axis.

However, I still have a problem that, when a limit switch was tripped, I used to be able to jog back off the switch slowly, and when the switch came off again it would do an Estop until I reset it, then it would go back to normal jogging speed. Now, with the limit switch tripped, once I've reset it I can jog at full speed either way, which isn't very good when you're at the end of the gantry travel.
I have adjusted the limit switch override buttons on the settings>special function tab but I can't really work out what they're supposed to do and whether i'm looking in the right place. 
Can anyone explain how to get the machine to behave in the way I have described when it has ridden onto it's limit switches?

Offline Overloaded

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Re: Appreciate some help with confusion over limit switch set up
« Reply #4 on: February 19, 2015, 10:52:16 AM »
Switch bounce will give you the second RESET. Otherwise it seems to be working normally.

From the manual:


 :)

Offline Joz

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Re: Appreciate some help with confusion over limit switch set up
« Reply #5 on: February 27, 2015, 06:44:00 AM »
Thanks for the info. Yes I forget about the manual sometimes  :)