Tuning PID parameters for hotend

I have a TEVO Tornado that I messed a bit with, so basically now I have:

• MKS GEN 1.4 board
• TMC2130 stepper drivers
• E3D v6 hotend

A few days ago the heater cartridge so I replace it with the old one that was on the hotend of the TEVO Tornado. Now ideally both should be 40 W from what I found online but after I replaced it the heating didn't work as expect so I set out to re-tune the PID parameters but no matter what value I try the temperature is always oscillating below the desired temp. Say the desired temp is 200 °C then the head temp will oscillate between 187-200 °C. I tried M303 auto tuning but with no luck for some reason the temperature can't go above 160-170 °C when auto tuning so I get a thermal runaway error.

I tried setting the D term to 0 and then to 1000 but the difference in behavior didn't change a lot which I think is weird... I thought the board might be going crazy so the timing for the PID controller is messed up but the thing is that is was working fine with the old heater cartridge. Any ideas?

• what did the PID tune return? – Trish Apr 21 '19 at 18:59
• There is also this question in the robotics group: robotics.stackexchange.com/questions/167/… – Perry Webb Apr 21 '19 at 20:31
• Disable PID in your firmware. Attempt to heat up. Can you reach reasonable temperatues, e.g. 230°C? If not, your heater cartridge or thermistor might not work correctly. You can check the resistance of the heater cartridge to calculate how much power it has (P = U^2 / R) – towe Apr 26 '19 at 11:09