Limit switches on 7i76 help

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20 Nov 2016 02:18 #83016 by Michael
I have been working on this all day with no luck. I am hooking up what will hopefully be limit and home switches on all axis of my mill. One switch to do both jobs with a soft limit on the opposite side.

I have SN04-P2 PNP NC proximity switches. 4mm detection 3 wires 8-30v, 0v and signal to a Mesa 7i76 hooked up as follows:
8-30v to 24v power
0v to ground
Signal to inputs 17-19 on tb5 (x,y,z respectively)

Switch lights up. No metal in front of it the signal leg puts out 24v. Metal in front of it and it goes to 0v. Turn on Linux CNC and I get "Joint 0 on limit switch error" also get errors for joint 1,2 but you get the idea. If I put metal in front of the sensor the LED goes off and I can move the axis. Seems to work the exact opposite that it should.

I have tried re wiring to every possible combo. Every limit and home setting pncconf (max limit, min limit, both limit) changed travel distances and home locations. And now I am here....lost.

Thank you in advance the help.
Mike

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20 Nov 2016 02:30 - 20 Nov 2016 02:32 #83017 by PCW
Replied by PCW on topic Limit switches on 7i76 help
This is expected, with the 7I76 and Normally closed PNP sensors, the 7I76 input pins will
read "true" when off the limits, LinuxCNC expects the limit switch signals to be false
when off of the limits so you must invert the sense of the limit signals

The easiest way to do this is to use the

card.0.7i76.0.0.input-XX-not

pins instead of the

card.0.7i76.0.0.input-XX

pins as the input signals for your limits switches in the hal file

(card is your particular FPGA card and XX is the input number)
Last edit: 20 Nov 2016 02:32 by PCW.

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20 Nov 2016 02:59 #83018 by Michael
Replied by Michael on topic Limit switches on 7i76 help
I did one last search after this post and found a mailing list post to click the invert box in pncconf. That did it. Thank you for the fast reply. Love the Mesa cards.

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