I've been playing with the ultimaker for a little while now, and and my last remaining issue seems to be with temperature. I think i have found what has been throwing me off. I searched, and found some stuff about temperature fluctuations but nothing solid with what i have been seeing.
My problem seems to be interference from when the stepper motors are on and the thermocouple readings (big black wire). I have seen this behavior when the print starts and enables the steppers for homing after heat up cycle.
Initial symptoms:
When i first turn on the ultimaker, it reports 24 C which is expected for room temp.
When i auto home the system the temperature instantly jumps to 10C and slowly climbs to 15-16c and stabilizes. And finally if i disable the stepper motors, the system will jump back to 24C instantly.
After i finally made the connection with the stepper motors, i now have the thermocouple wires, running outside of the ultimaker, instead of running through the insides, which i'm assuming they are supposed to be. I still get a 2C drop, A lot better than 10-15C. But i also have a huge wire randomly hung up on the outside. (With the steppers on i can move the wires closer and further from the y axis stepper and watch it fluctuate 2-5C more.
I check the temperatures through both the ulticontroller and pronterface console. And have verified all the wiring on the thermocouple board on the extrusion head is tight.
I'm worried i may have something wrong, or a grounding issue with the thermocouple wires. Also i'm assuming the thermocouple wiring is supposed to be routed along one of the back sides with a stepper motor? (it is rather long). Has anyone seen this behavior or have any suggestions?