Recompiling firmware for Rambo to change Z limit switch io

Sorry the title isnt very good but wasnt really sure how to explain it.

I bought, built and have been running a Rambo dual end stop kit from Ryan. All seems to be performing and I was getting used to the machine. Then, due to some messy wiring I accidently shorted the z min limit metal plate to 12V. I think this blew the io pin up. I think its a shame because I know its my fault but I think they could have made it more robust relatively easily.

Anyway, I thought I might just be able to recompile the firmware to swap the Z min and max switches as I wasnt using the max limit. I compiled the firmwre for dual endstops ( I am not sure if I needed 32 steps or not but did not compile for that ) and somehow the machine seems to be working. It doesnt feel quite as smooth though. Not sure if there is some acceleration parameters? It just seems a bit quick when I use repetier host to manually move it. Possibly just me though.

The problem comes though that when I home the z axis now, it seems to go down and detect the plate but it does not go back up for the slow fine position detect. I think this is because that part of the firmwware might be using the max limit switch ( which is the min pin i blew up ) and that is always closed now. So it instantly doesnt go up. I am thinking this is happening but not totally sure.

Is there another pin I could safaly map the z max limit to and also do I need 32 step compile and are there any other paramters worth compiling in?

Any helps would be great.



Sorry I had somehow missed your post.

Have you sorted this out? Using Z max should be okay, if not there are a few other open pins on the board.

Before when I used to home Z it would move down until it touches the plate and then rise up a bit and then slowly drive down to get a very accurate home position. Now it just stops on first detection of the z plate.

I did have a look through the schematic but did not find a pin I could relocate z max to. A few suggestions would be great.




I have an open pin shown on my ultimachine page.

Hi, I did look on the page but it isnt clear to me what pin I could assign. I saw the M1,M2,M3 header bit? But then it said PIN23 is shared with Y MAX and that go me confused.

Do you have a bit more info on what pins are I can use?


In that header there should be 3-4 unused pins, have a look at the Rambo wiki for a list and numbers.