Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: tomcord on January 18, 2015, 12:34:14 PM

Title: advice on trouble shooting an error required
Post by: tomcord on January 18, 2015, 12:34:14 PM

Hi, some help required please. I helped a mate set up a small cnc router in his workshop 2 years ago for trimming carbon and glass fibre kayak paddles. It has worked perfectly for the last 2 years. Now we have a fault and I am no longer that familiar with Mach 3 as I haven't been playing with it for a while. So the PC, Gcode, machine etc. has not changed in the last 2 years. The machine has one stepper motor for z axis with reed switch and magnets for the limit switches. One for x axis with a chunky microswitch at either end for limits. Two stepper motors for Y axis (one slaving the other) with chunky micro switches. A Kress router for the spindle.
So, the machine runs about half way along the kayak blade blank, then switches of. No limit switches appear to have been activated in the diagnostics screen, but the error message lower left says limit switch triggered. We are at least 100mm from any limit switch.

Is there any kind of log file I can access and share to find out what is happening? Is there any kind of feedback from the stepper motors that indicate overheating or over load? It always around the point on the blade where the thickness increases from 1.5 to 2.25mm, so there would be a bit more load on the spindle and stepper motors, it doesn't always stop in the same place, but it is always around that area. If one of the stepper motors or spindle was overloaded at this point, would it feedback anyhow to the controller?.

If you start the machine again from the same point it stops again almost immediately. But it doesn't cut out all the time, sometimes it will trim up to 10 blanks just fine, then suddenly cut out.

We are thinking maybe a short on the Z axis limit wiring that just kicks in around that point, maybe some chafing in the wires, but not long enough to see the lights on the diagnostics screen light up, could this happen or would they stay permanently lit?

Any advice appreciated.

Thanks

tom

Title: Re: advice on trouble shooting an error required
Post by: ger21 on January 18, 2015, 01:30:59 PM

Could be a short, or electrical noise. Could be very hard to track down.
If it's noise, a simple fix is to increase the Debounce in general config. Try 2000-3000.