View Full Version : Limit switch issues?!?

28-09-2012, 03:29 PM
Can anyone help before I take a sledgehammer to my machine? Im having some issues setting my limits up.

To start, im using a zp5a bob. 2 limits wired in series NC on each axis using a total of 6 switches and 3 inputs. Good so far? Now, when i go to setup in mach, I set my switches up to the correct pins. Ill start with x as an example first but all axis act the same. No switches on x are pressed, mach says 'limit switch triggered', so press the switch in, it goes away......right so switch working good, change active low setting to reverse right?....wrong. Says limit triggered no matter if switch open or closed?!? Checked switches with meter, all continuity test fine. So I change switches to NO config, no joy. Switch does nothing at all. So the only time i can get the switch to do anything is when its on a NC config, and active low OFF, then the switch operation is the wrong way round!

28-09-2012, 03:41 PM
Hi Jon sent a PM.

28-09-2012, 08:55 PM
Hi Jon I have the same breakout board with the same problems the board is inverting the signal sent to the parallel port, I have just received another one I ordered to see if this would fix the problem, but I think if you are finding the same problems then it is not going to cure the problem.
I also had to put the step timing in the motor tuning menu to 5uS to get the stepper motors work, I'm using 542 stepper driver's.

I will post if the replacement board cures the problem when I fit it tomorrow.


28-09-2012, 10:20 PM
My issues are related to noise, the bob is fine. I have managed to sort it in a fashion(thanks for help jazz, top bloke) but there are a couple of rewiring options i need to try to fully rectify it. Confident ill sort it tho. Ill post my final solution when ive sorted it.

28-09-2012, 11:01 PM
Thank you, I hope you get it sorted out ok,and will be interested in your final solution.

28-09-2012, 11:28 PM
I know what you're saying, and I didn't bother with them on my last machine either. But, I can't honestly say that I never drove it into the side a few times either ;) I also wanted to use them as home switches too but I'm going to do it all a different way now. Would be nice to be on the ball 100% of the time, but only takes 1 time driving it where it shouldn't and I may end up having to rebuild it for the sake of a few switches.

28-09-2012, 11:51 PM
Yeah they are a bit flimsy for homes, that's why I've acquired 3 of the best limit switches money can buy from somewhere for homes.

29-09-2012, 12:23 AM
Swim borrowed them from work for testing. That is all.:barbershop_quartet_

29-09-2012, 07:12 PM
I'm unsure where I read it but for those not machining metal can use hall effect devices with great repeatability.

06-02-2014, 04:46 PM
Hi Jon, Would you mind sending me the rewiring options you considered - I also have the ZP5A breakout board and I'm finding the same problem (I think) after wiring all my limit switches up as NC and then wiring them directly into the breakout board. I've also been wondering if the user guide is wrong since I've managed to set up my homing by wiring the metal plates into the terminals marked GND rather than the one marked with the pin number e.g. (for instance) P14. It could be my misunderstanding but the Chinglish instructions are a right royal pain for helping me to understand!

06-02-2014, 06:37 PM
Sorry this was a duplicated post (and I cant see how to delete it!)