Limit Switches Not Working

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clothesby
Posts: 4
Joined: Fri Jan 31, 2020 2:24 pm

Limit Switches Not Working

Post by clothesby » Fri Jan 31, 2020 2:34 pm

I'm having trouble getting my limit switches to work. I have one wired up for each axis ("NO" connected to X/Y/Z and "GND" connected to "GND" on the board). I have tried setting $20, $21, and $22 to 1 with no change. Communication is otherwise working fine as I can jog each axis of the machine. One clue that might be important is that I am reading 0V when I take a multimeter to the limit switch (open or closed). Am I missing a connection somewhere? What else can I check to narrow down my issue?

Bertus Kruger
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Re: Limit Switches Not Working

Post by Bertus Kruger » Tue Feb 11, 2020 6:31 pm

$22 set to 1 will enable endstops.

Could you please post how you have wired the end stops?

This is how it should be done...
https://wiki.protoneer.co.nz/Raspberry_Pi_CNC#End_Stops

Also can you post your GRBL settings... enter in GRBL $$

clothesby
Posts: 4
Joined: Fri Jan 31, 2020 2:24 pm

Re: Limit Switches Not Working

Post by clothesby » Wed Feb 12, 2020 1:58 am

My end stop wiring looks like this: https://imgur.com/a/BPoSCCs

Current GRBL Settings:
$0 = 10 (Step pulse time, microseconds)
$1 = 25 (Step idle delay, milliseconds)
$2 = 2 (Step pulse invert, mask)
$3 = 0 (Step direction invert, mask)
$4 = 0 (Invert step enable pin, boolean)
$5 = 0 (Invert limit pins, boolean)
$6 = 0 (Invert probe pin, boolean)
$10 = 3 (Status report options, mask)
$11 = 0.010 (Junction deviation, millimeters)
$12 = 0.002 (Arc tolerance, millimeters)
$13 = 0 (Report in inches, boolean)
$20 = 0 (Soft limits enable, boolean)
$21 = 1 (Hard limits enable, boolean)
$22 = 1 (Homing cycle enable, boolean)
$23 = 0 (Homing direction invert, mask)
$24 = 25.000 (Homing locate feed rate, mm/min)
$25 = 500.000 (Homing search seek rate, mm/min)
$26 = 250 (Homing switch debounce delay, milliseconds)
$27 = 1.000 (Homing switch pull-off distance, millimeters)
$30 = 1000 (Maximum spindle speed, RPM)
$31 = 0 (Minimum spindle speed, RPM)
$32 = 0 (Laser-mode enable, boolean)
$100 = 250.000 (X-axis travel resolution, step/mm)
$101 = 250.000 (Y-axis travel resolution, step/mm)
$102 = 250.000 (Z-axis travel resolution, step/mm)
$110 = 500.000 (X-axis maximum rate, mm/min)
$111 = 500.000 (Y-axis maximum rate, mm/min)
$112 = 500.000 (Z-axis maximum rate, mm/min)
$120 = 10.000 (X-axis acceleration, mm/sec^2)
$121 = 10.000 (Y-axis acceleration, mm/sec^2)
$122 = 10.000 (Z-axis acceleration, mm/sec^2)
$130 = 200.000 (X-axis maximum travel, millimeters)
$131 = 200.000 (Y-axis maximum travel, millimeters)
$132 = 200.000 (Z-axis maximum travel, millimeters)

Is there additional setup required? If I jog an axis then trigger the end stop, should the motor stop at this point?

Thanks.

Bertus Kruger
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Re: Limit Switches Not Working

Post by Bertus Kruger » Tue Feb 18, 2020 12:03 am

Your end stops are wired incorrectly.

The common pin in your image is actually the probe pin and not gnd

use a gnd pin from the above or below green connector.

clothesby
Posts: 4
Joined: Fri Jan 31, 2020 2:24 pm

Re: Limit Switches Not Working

Post by clothesby » Tue Feb 18, 2020 12:53 am

Thank you so much, that was it! End stops work fine now.

Bertus Kruger
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Re: Limit Switches Not Working

Post by Bertus Kruger » Tue Feb 25, 2020 6:55 pm

clothesby wrote:
Tue Feb 18, 2020 12:53 am
Thank you so much, that was it! End stops work fine now.
Good stuff!!! :)

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