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PID Auto tune Fail
Posted: Fri Mar 11, 2016 6:52 pm
by jmargush
Recently I noticed that my hotend would reach Target temperature and during the print it would cool down while printing.
I decided to run a PID Autotune test and I entered the command M303 S200 into the g-code Command Terminal (Software Version 1.5).
It would climb to 130 degrees and would stop climbing. and a few minutes later I got an error message saying PID Autotune failed! timeout.
At this point I don't have a solution because I have never run into this. If you have any suggestions they would be very much appreciated. Thanks!
Re: PID Auto tune Fail
Posted: Fri Mar 11, 2016 7:03 pm
by Jimustanguitar
What's your drive max set to? If it's considerably lower than 255 you aren't sending full power to the heating resistor.
Re: PID Auto tune Fail
Posted: Fri Mar 11, 2016 7:42 pm
by jmargush
I think that may have fixed my problem. I am running a PID right now.
Re: PID Auto tune Fail
Posted: Fri Mar 11, 2016 7:50 pm
by jmargush
Same thing happened sadly. Sorry
Re: PID Auto tune Fail
Posted: Sat Mar 12, 2016 5:32 pm
by teoman
One of the resistors may have gone bad. Check the resistance.
Re: PID Auto tune Fail
Posted: Sat Mar 12, 2016 7:34 pm
by jmargush
teoman wrote:One of the resistors may have gone bad. Check the resistance.
I checked the Ohms of the resistors with my dad and while checking it I noticed that both resistors were connected by a crimp connector and didn't know if I should cut it off to measure them separate from each other.
[img]
http://snag.gy/S70lv.jpg[/img]
My dad and I didn't want to cut them and scrap the resistors in case they were not broken. We measured the Ohms and got 9.8 ohms by measuring from the base of each resistor where the lead first begins, but I felt like it was measuring both resistors. My dad said that it could be that one is broken and that 9.8 is in the range of the 6.8 spec. listed on the website. Thanks for your time.
Re: PID Auto tune Fail
Posted: Sat Mar 12, 2016 9:00 pm
by Xenocrates
That will measure both resistors.
As the resistors are in parallel, when they are functioning, the resistance should be lower than any of the resistors in the circuit. It should in fact be the sum of the values to the power of negative one, to the negative first power (Each value to ^-1, then raise the total to ^-1).
This suggests that both are fried, as there should not be any resistors off their nominal value by nearly 50%.
You have the option of either replacing like with like, or upgrading to a heater cartridge and threaded thermistor. See the instructions for both here:
http://forum.seemecnc.com/viewtopic.php ... tap#p86970