Frage Limit switch triggered

Hello,

It`s been a couple days since i finished the assembly of my stepcraft 420 v2 and I`m trying to procceed with the first steps manual provided with the uccnc software.
I`m having a problem with the reference switches (both y and x/z) as they appear as triggered in the software even when not pressed. To check for wiring problems i connected the switches in the e-stop port (which was working correctly) and they functioned correctly. The stepcraft profile that came with uccnc was configured with limits on pin 12 port 1, so i guess it`s correct. I can only think of a defective control board, and im going to check the voltage on the switch connectors as soon as i find my multimeter.
Is there any other possibility i may have overlooked?

Hi sgripp,

Use the "Diagnostics" screen to see the state of the inputs as seen by UCCNC - you should be able to determine if the s/w is responding to switch operations at the input to the control board (port1,12 is correct).

If the whole UCCNC package is functioning correctly, then when port1,12 is at logic 1 (input open circuit) the "Diagnostics" page I12 indicator will show green, as will X,Y,Z Home and X,Y,Z + Limit.

Peter

That`s the problem, it is not responding. The input 12 keeps green wether i press the switches or not

Then it sounds very much like a hardware fault on the control board to me - unfortunately.

If you are confident, can you check continuity between the screw connector and the I12 pcb track, it will be soldered on the under side of course with a PTH through to the track on the top of the board- there might be a dry joint or a break in the track leading to a pullup resistor and the interface chip . A strong magnifying glass will help a lot.

I've attacked a picture for reference - the track concerned is the leftmost of the three arrowed. The tracks will be covered with solder resist, so be aware of that when you do a continuity check - perhaps the PTH nearest the group of resistors might be the best place to try. The tracks are labelled close to the screw connector.

Good luck!!

It could also be, that one of the switches are cabled the wrong way.
I would check this first.

The switches have already been proven to operate correctly by patching them into the ESD circuit - so it does point to a board fault rather than a switch fault.

The indicator at green indicates an open circuit, black indicates a short to ground, which is the untripped condition.

I din`t have time the last couple weeks to continue testing with the machine. This weekend however, i kept testing trying to find the cause of the problem. I re-checked the continuity of all cables and to my surprise the x/z limit cable was giving an intermitent continuity, I tried moving the cable and found a position that it kept cuurent flowing, and then i could reset the machine through UCCNC.
It wasn`t a control board fault after all, just some bad luck ^^. It took some time to replace the cable but its working perfectly now. I checked the original one and it seems that it was broken at the right angle curve when going down the gantry

Glad you solved it and that your control board is healthy.

Intermittents are a b*****d to cure!!