Limit Switch Wiring Problems - Again!

TomS said:
Checked voltage across pin 10 and ground terminal and it was zero. Shouldn't it be 5VDC?
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It should be 0 V with the switches connected and closed. Check again with a switch activated, then it should read 5 V

Is the pin set properly in Mach3, I think it should be Active High,, but try Active Low also
 
JimDawson said:
It should be 0 V with the switches connected and closed. Check again with a switch activated, then it should read 5 V

Is the pin set properly in Mach3, I think it should be Active High,, but try Active Low also
Click to expand...

I'll check it in the morning. Each of the switches are set active low which is the setting they were at when I had the switches wired to separate inputs. I'll set them active high and see what happens. Thanks again for your help.

Tom S.
 
to be sure, you would need to know if the BOB you are using has built in pull-up resistors. If so then the way you have wired it should work and as Jim says, with no switches activated it should read ZERO volts at Pin 10 and with any one of the three activated it should read +Vdc at pin 10. However if the BOB does not have internal pull-up resistors then you will need to move the wire that goes from the Z-Limit switch from the -Vdc terminal to the +Vdc terminal. Then measure again and you should get +Vdc with no switches are activated and Zero volts when any one or more limit switches are activated. Once you verify that it works with an volt meter then you you can set Mach3 to Active Hi or Active Lo depending on which of the two configurations that you are determ that you have. My guess from your symptoms is that you need to use the second configuration where you have the last switch in the chain (Z-Limit) connected to +Vdc and not -Vdc like you show in the schematic.
 
Boswell said:
to be sure, you would need to know if the BOB you are using has built in pull-up resistors. If so then the way you have wired it should work and as Jim says, with no switches activated it should read ZERO volts at Pin 10 and with any one of the three activated it should read +Vdc at pin 10. However if the BOB does not have internal pull-up resistors then you will need to move the wire that goes from the Z-Limit switch from the -Vdc terminal to the +Vdc terminal. Then measure again and you should get +Vdc with no switches are activated and Zero volts when any one or more limit switches are activated. Once you verify that it works with an volt meter then you you can set Mach3 to Active Hi or Active Lo depending on which of the two configurations that you are determ that you have. My guess from your symptoms is that you need to use the second configuration where you have the last switch in the chain (Z-Limit) connected to +Vdc and not -Vdc like you show in the schematic.
Click to expand...

I thought about your response and realized I might not have been clear in my explanation when I posted the wiring diagram. My BoB is powered through a USB hub which means I don't have +Vdc or -Vdc terminals. I'll post my wiring diagram in the next couple of hours.

Again, thaks for your help.

Tom S.
 
I am making all my comments off of the schematic that you shared above where you clearly show a -Vdc and a -Vdc. I just read your text to say that you did not implement a power supply like the diagram shows. So you will have to find a +Vdc somewhere. What is the Brand and model of your BOB?
 
Here is my wiring diagram and my BoB manual. My limit/home switches worked when they were wired to separate inputs. That's why I'm confused as to why they don't work when wired in series.

Tom S.
 

Attachments

  • Limit Switch Wiring Diagram 9-28-2016.pdf
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  • BreakOut_V5.pdf
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ok, let take a look at this. I think we can get this figured out but it will be this evening before I can look into it.
 
I see the problem, you are shorting the switches with the jumpers.

try it like this

upload_2016-9-29_9-16-59.png
 
It has been a while since I went through this but I recall if you gang all the Home switches together you have to Home each axis individually and not use the Ref All Home button.
 
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