Mesa 7i96 - getting limit switch status in python

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cody
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11 Jul 2020 22:59 #174338 by cody

Mesa 7i96 - getting limit switch status in python was created by cody

I've fumbled around the LinuxCNC python interface guide for a while trying to find how I can read the status of the limit switches. For example, I want a 1 if a limit switch is pressed and a 0 if it is not pressed.

I ran the s.din command and was able to read the other inputs to my machine (prox switches and other sensors) just not limit switches. I press the limit switch and see the LED light up on the Mesa board, and the limit switches work to home the robot, I just can't figure out how to read whether they are pressed or not.

Does anybody know if this is possible to do?

Thanks in advance!

Cody

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phillc54
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12 Jul 2020 03:41 #174351 by phillc54

Replied by phillc54 on topic Mesa 7i96 - getting limit switch status in python

You could try reading the hal pins like joint.0.pos-lim-sw-in joint.0.neg-lim-sw-in etc.

The following user(s) said Thank You: cody

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cody
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12 Jul 2020 14:10 #174387 by cody

Replied by cody on topic Mesa 7i96 - getting limit switch status in python

Thanks for pointing me in the right direction! I got it figured out. I've added the python code below to make this work if anybody else is interested

import hal
import time

while 1:
    h = hal.component("passthrough")
    limitX = hal.get_value("joint.0.home-sw-in")
    print(limitX)

    time.sleep(0.1)

    h.exit()

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cmorley
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12 Jul 2020 18:37 #174413 by cmorley

Replied by cmorley on topic Mesa 7i96 - getting limit switch status in python

linuxcnc.org/docs/2.8/html/gui/GStat.html

specifically
hard-limits-tripped

(returns bool, Python List) - Sent when any hard limit is tripped. bool indicates if any limit is tripped, the list shows all available joint’s current limit values.

The following user(s) said Thank You: phillc54, nkp

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