[Jakeller449]

So I have my DIY CNC running with a G540. I installed limit switches and immediately started getting false triggers. I wired and grounded everything to best practice standards but the 1617 Router is just spiking too much noise. I removed the Z axis switch and the problem went away entirely so I know it is isolated there.

I am running UCCNC with a UC100 so unfortunately I cannot use the debounce setting that is built into UCCNC. That leaves me with having to install a hardware filter. Right now my plan is to install a 2kOhm resistor and a 0.1uF capacity to try and filter out these noise spikes. Is my thinking correct and would I wire them in series like shown in the drawing I attached?

[wizard]

are you running shielded cables? That is the first thing I would consider and your drawing doesnt make that clear. I don't know a lot about the I/O port on this board but adding series resistance could be a bad thing so I wouldn't do that until consulting the manufacture.

The problem is that the series resistor in combination with the current limiting resistor in an optical coupler might lower to the current too much to the diode so that it will not turn on correctly. So how well a series resistor will work depends entirely upon how the inputs are designed. You might do fine with a small cap directly across the input but still i'd get on the manufactures forums to find the recommended approach.

[Al_The_Man]

Do you have all powers supply commons referenced to earth GND via a star point ground, together with the service ground?
Al.

[Jakeller449]

Do you have all powers supply commons referenced to earth GND via a star point ground, together with the service ground?
Al.

Yes. All cables are shielded as well with the shield wire open at the switch end and connected back to the star point ground in the panel.

[Al_The_Man]

As well as the power supply common shown in the post one drawing?
Al.