I recently picked up a techni-isel gantry router. Not sure the exact model, roughly a 10"x13"x4" envelope. It's running the original TI steppers, and the original TI drives with a homemade parallel port breakout inside hooked up to a machine running Linux CNC. I've run a couple small tests on it without issue, but I recently tried a larger engraving job. Partway through the job the machine changed the x-axis zero on me! It did this twice, not quite in the same spot in the program, but roughly by the same amount (30mm). See pics below. The machine didn't know the zero had changed, the realtime display on the LinuxCNC screen shows it cutting where it's supposed to, but the x-axis zero moved. I thought the first time it might have been something I did. I had run about half the program as a test before loading the real part, and I wondered if somehow it had retained my other zero. But the second time all I did was zero the machine, load the program, and go, and it happened again. Any ideas on what's causing this? The machine also has some trouble occasionally when homing the axes with noise causing a false positive on the home switches. If a home switch went off during the program could it cause this?

What the machine thinks it's doing:


What it's actually doing (twice):




Similar Threads: