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I’m trying to upgrade a cnc I just purchased from UC100 to the Axbbe board which I retro fitted to my previous machine.
The problem I’m having is with the 2 wire reed limit/home switches which are similar or the same as the ones in the attached PDF. What’s happening I believe is I’m seeing the hard limit/limit led’s flicker in diagnostics which is triggering the reset.

I don’t understand why they worked fine on the UC100 but the AXBBE is picking up this spike so to say and triggering the stop.

I don’t know how the UC100 works any differently to the AXBBE when it comes to the wiring of the sensors. On the UC100 I believe each sensor supply wire was on a separate pin and the return wires went to ground on the breakout board. As shown in the picture, of you click on it I've marked where the limit cables went to on the BOB attached to the UC100.

Was the USB supply through the UC100 powering the sensor and when the magnetic reed switched opened or closed this went to ground? There wasn’t any other power supply to the reed switches and In Mach3 (the reason I’m swapping boards btw) the pins here set to active low.

I am wondering if it is power/ voltage/resistance related as the switches say 0.5A 200v rating and the 24V supply to the AXBBE is 2.5A. What would the UC100 have supplied?

I have tried supplying 24v through the sensor and the return trigger wire to the positive input pin on the AXBBE with he negative pin to the 24v negative and still have the flickering trigger. I’ve also done it the other way with he 24v negative to the input of the reed switch and the return wire to the negative input pin and 24v positive to the positive pin again I still have the flicker.

I don’t want to change the sensors to 3 wire ones if possible as that would mean a complete rewire of cable through the machine.

What are my options or what have I done wrong please guys as I’m stuck on using the machine until I’ve got passed this problem which I thought would be a straight forward swap when everything worked before.

You having this problem because the AXBB-E can read high speed signals like incremental encoders, so it's isolated inputs can throughput high speed signals and so noise spikes are also going through causing problems in your system.
What you can do is you can configure the input debounce filter to filter out the input signals in the motion controller or you can filter your input signal electrically, e.g. place a 100nF ceramic capacitor between the input+ and input- of your isolated input terminals.

[quote="cncdrive"]You having this problem because the AXBB-E can read high speed signals like incremental encoders, so it's isolated inputs can throughput high speed signals and so noise spikes are also going through causing problems in your system.
What you can do is you can configure the input debounce filter to filter out the input signals in the motion controller or you can filter your input signal electrically, e.g. place a 100nF ceramic capacitor between the input+ and input- of your isolated input terminals.[/quote

Thank you for clearing that question up.

But how did the sensors actual operate/trigger with the UC100 when the what i would call the power wire was connected to ground on the bob and the trigger wire from each sensor to one of the inputs?