Thanks Hood and John!

iqbal, listen to Hood and John, they give as solid advice as you will find.

Brett

Brett does too. Even when dead tired solving the rest of our problems!

So finally
Removed the debounce from Mach3
Changed the debounce in SS from 500 us to 10 us.
Added four 0.1 uf caps to each of the inputs.

The system is able to home correctly on all 3 axis.


One small thing that would have really helped, if the limits lights on the diagnostic page were sticky. That is, once its set, it remains set until its cleared.
A small momentary noise spike will trigger the limit, but there is no visual indication on the panel that such an event has occurred . That kept me wondering as to what the problem could be.

One small thing that would have really helped, if the limits lights on the diagnostic page were sticky. That is, once its set, it remains set until its cleared.
A small momentary noise spike will trigger the limit, but there is no visual indication on the panel that such an event has occurred . That kept me wondering as to what the problem could be.

That's exactly how they work now. The led comes on when the input is active and turns off when it is deactivated. The problem is you either have bouncy switches or your picking up noise. This can have the same effect as turning the input on and off faster than you can see and/or faster than your graphics can update. Kind of hard to program for something that doesn't work as it should. If you had to add 4 caps to each input and set the debounce to 10 in the SS you need to look at the link in my first reply.

Brett

The switches have mechanical hysteresis, they are certainly not bouncy.
They have contact noise, but once they change state they stay set.

The diagnostic page is limited as a visual guide. A trace file recording the events can also help. Especially if some event like that is triggered during a long job run.



Iqbal

 One small thing that would have really helped, if the limits lights on the diagnostic page were sticky. That is, once its set, it remains set until its cleared.
A small momentary noise spike will trigger the limit, but there is no visual indication on the panel that such an event has occurred . That kept me wondering as to what the problem could be.

I don't think it is necessary to "latch" the LED's on.
The message ticker on the main screen notifies you as to what the fault condition was.
External E-Stop requested ... or ... Limit Switch triggered Mach goes into E-Stop either way then requires a RESET.
The ticker is a great diagnostic tool.
IIRC,
Russ
 

Yes, both of you are right. And this is good learning experience for me.

The limit switch was triggered continuously and immediately after enabling the limits, without the yellow lights lighting up even once.
I was trusting the yellow light more than the ticker.

In hindsight since the ticker is sticky, its much more reliable than the flicker of the yellow light.


Iqbal