pid auto tune for heated bed not responding

[david]

I am at the step of working out the calibrations .I already did the printer head pid auto tune ,which worked out fine. when I tell repeiter to do the command it just sits and does nothing says one command waiting but in the bar below shows pid autotune start. the heated bed works, tried the bed pid before heated up but no communication with the repieter .

[geneb]

The bed takes longer to heat, so the auto-tune process will take longer. Start it and let it finish.

g.

[david]

the lcd said idle during heating then killed after done. no information on the pids were there and yet after it stopped heating the program still said 1 command waiting

[geneb]

The LCD won't give you any info about the auto-tune process.

It's possible that the bed took too long to heat and it aborted. What command are you sending to heat the bed? Does it ever reach that target temp?

g.

[david]

I am using "M303 P1 S60" command .once, it reached target temp but then it dropped like normal, but the repeiter software did not register any kp, ki, or kd's.

[Jimustanguitar]

I've had trouble with the idle timer on the bed PID too. I went searching for the timeout in the firmware and was able to change it, but i can't remember what I searched for to find it now... I'll post it if I remember.

[david]

bump

[smiley]

bump. my hot end autotune is timing out too. temp gets to the setpoint and then decays, never starts heating up again. is autotune broken?

[lordbinky]

Hmm... hotend autotune timing out is typically a sign something significant is wrong. For me, it was a heater cartridge being 40 watts @ 24 Volts, which made it too slow for 12 Volts input. Check your heating resistors/ heater cartridge and your thermistor. The tip of the thermistor is the most sensitive part (the glass should be thinnest there) and should make direct contact with the hotend inside of the thermistor hole. If the RTV silicone barrier happened to make it between the tip and the hot end it will throw your measurements off because it is a barrier as good as the silicone oven mitts, it's also why it's okay to have RTV on the SIDES of the thermistor but "bad things happen"™ when it interferes with the tip of the thermistor. It very much is a insert-and-don't-adjust process for the thermistor. There are other ways such as using kapton tape to secure the thermistor into the hotend such as some hotend manufacturers suggest. The important part is the tip of the thermistor is making direct on metal contact and that the thermistor does NOT pull away from the hotend when printing (more 'bad-things-happen'™ )