Hello,
I am working with a rather large 3d printer. I'm running several thermocouple band heaters that I run back to the duet3d board. The run length is approx. 52 feet (16 meters). What I am experiencing now is that once I enable the motors on machine, the thermocouple reading go to 2000 (wire short). I tried the following to try and figure out where my problem is.
I run a separate wire, away from all components, from the duet3d to the thermocouple. If the band heaters are not installed (floating in the air), the thermocouple reading is correct and steady. Once the band heaters are touching the machine (as installed), the reading goes haywire. This only happens with the motors energized.
Is the issue my motors leaking noise into the system. is there a way for me to isolate them?
They are powered by a different power supply then the duet3d, and everything is grounded to the machine ground.
My understanding is that if my thermocouples weren't isolated properly, I would see a short on the MAX chip at all times, yet I only see it with the motors energized.
My other idea was noise picked up on the long length of the wire, but the installed wire and the free hanging wire away from the gantry show the same effect.
My other idea was to use a Expansion Board 3HC and connect all the thermocouple daughterboards there, and then run CAN back to the machine, but that was because my first ideas was noise in the long thermocouple leads.
Thank you for any help