Need Help!- CNC Router Parts breakout board Limit switches

[Plan_B]

Hello,
Does anyone have any experience setting up limit switches using CNC Router Parts breakout boards? This is probably some silly oversight on my part but when I measure the sensor input (to the board) wrt that channel's GND I get 0V. Am i supposed to see 5V there?

My understanding is that one way to wire the switch is NC, which I thought should be equivalent to closing the circuit between Sens1 and Sens1 GND. Opening it would be equivalent of activating the switch.

With no potential difference between the pins I don't see how that would work. I measured the voltage across the "12VDC sensor power supply" (provided on the board for every sensor input port) and the GNDs and I get 5V. Assuming the 12V may be a typo in the manual I went on to try connecting the 5V to the sens1 pin and both pulling up and pulling down the pins.

Any way that I try I can't seem to get the signal to be recognized in mach3.

Any ideas would be greatly appreciated!

[Euro3D]

Did you resolve the issue.

The Sense inputs on the CRP breakout board for the limit switches need to see 12v on the active wire or 0 v (high or low) which is dip witch settable, don't short the 12v just put +12V on the active wire, ie the switch only switches one wire the other wire is the ground reference for the Sense input, hope this make sense.

Cheers

John

[brtech]

Don't have any direct experience with that BoB, but usually, if that's what you see, you connect a positive voltage, Euro3D says +12, through a resistor, in this case something like 330 ohms (not at all sensitive), and then connect your limit switches NC and common contacts in series, with the last one connected to ground (of the 12 V power supply). Normally the ground of the +12 and the ground of the motor supply, and the green wire ground from the power cable is connected to the frame at one point.

This resistor (a "pull up" resistor) makes the input active high = any open switch makes the input +12. If all the switches are normally closed, the input is grounded (0V). Doing it this way means a broken wire shows up as a limit.

[freecncplans]

You do not need a pull up resistor to make the switches to work with this breakout board. I don't have one on my switches and it works fine.

You have the option on the board for high or low. You need to use two wires, one is common and the other two are not to be used together.

I *think* I used red and green, set the switches to low and then set Mach3 to active high. As long as you use the green wire to either the red or black (not both or red to black), you shouldn't hurt anything. I measured 12 volts on my board.

I went to the diagnostics screen in Mach and changed settings until I saw the lights do what I wanted.

I tried to use the magnetic switches with this board but I couldn't get the switches to activate as they need a steady volt supply. Being in a hurry I gave up and went with mechanical switches.

Sean