Limit switchs

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29 Dec 2019 20:24 #153494 by jeffie-3
Replied by jeffie-3 on topic Limit switchs
O.K. I am getting the same errors with the _not and without it. Now all the limit switches are wired NC. I checked the voltage at the 7i77 board. It is coming off the 12 volt supply but it is at 2 volts. I am using the bottom row. The 1st slot is empty. The X is at the 2nd slot and Y is at the 3rd slot, and the +Z is at the 4th, and the -Z is at the 5th slot. I am not completely lost.

Error
joint 0 on limit switch error
joint 1 on limit switch error
joint 2 on limit switch error

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29 Dec 2019 20:27 #153496 by Leon82
Replied by Leon82 on topic Limit switchs
I believe you will need to get at least 5 volts there.

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29 Dec 2019 20:37 #153498 by jeffie-3
Replied by jeffie-3 on topic Limit switchs
It is connected to the 12 volt supply. It just shows 2 volts at the board.

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29 Dec 2019 21:00 #153503 by jeffie-3
Replied by jeffie-3 on topic Limit switchs
Is it better to use 5 volts? I am coming in on the end of the build. My friend who wired it, has a family member who is ill and is not available. Plus I just need to know how to do all of this. I have another mill I would love to turn into a CNC.

Thanks,

Jeff

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29 Dec 2019 21:07 #153504 by Leon82
Replied by Leon82 on topic Limit switchs
I don't know for that card specifically, but most of them use between 5 and 32 volts.

Double check the tightness of the screws.

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29 Dec 2019 21:10 #153505 by PCW
Replied by PCW on topic Limit switchs
5V is generally a bad idea for mechanical switches

I think it would helpful for debugging to use the "watch" function or
halmeter and look at the 7I77 input pins as you operate the
limit/home switches by hand...

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29 Dec 2019 21:16 #153507 by Leon82
Replied by Leon82 on topic Limit switchs

5V is generally a bad idea for mechanical switches


Is that because it may not sense the trigger in time?

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29 Dec 2019 21:19 #153508 by PCW
Replied by PCW on topic Limit switchs
its because mechanical contacts are less reliable at lower voltages
(and a input detecting 5V signals will have lower noise immunity than one
detecting 12 or 24V signals)
The following user(s) said Thank You: Leon82

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29 Dec 2019 21:22 #153509 by tommylight
Replied by tommylight on topic Limit switchs
Where is the other wire from the limit switches connected to ?
They should all be connected to 12V in your case, not to GND.

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29 Dec 2019 21:30 #153510 by jeffie-3
Replied by jeffie-3 on topic Limit switchs
The wires used are green and white. The white wires run to the 7i77 card bottom row. The green wire runs to a 12 position terminal block. The 12 volts are run to the 1st 3 terminals. Each sets of wires run to each of the limits switches and one set of wires run to a e-stop switch that also doesn't work.

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