HE280 temperature steady state error

[moo77777]

I have recently been having a problem where when I assign a temperature to the hot end, it holds at about 5°C below the value I have issued. For example, if I am asking for 225°C at the hot end, the controller dances around 220°C and never starts the print.

There isn't an issue with the heater being able to achieve proper temps. I can set the temp to 230°C and it climbs up to and holds 225°C no problem. For starting prints I have had to resort to bumping the temp and letting it climb followed by dropping the temp to start the print and moving it back up again for the duration. All this has to be done using the knob and LCD.

It seems to me like an issue with the PID controller that is making the temperature changes but I am not certain. But I find that odd because it was working fun for the most part and only started having issues in the last 18 hours after a bunch of use.

Has anyone had any experience dealing with this or know what might be the issue?

[U.S. Water Rockets]

I had this issue because I calibrated in the middle of the summer on a really hot day and the A/C wasn't really stabilized in the room, when the winter came the ambient was a lot cooler at times and the hot end would not get up to where it was supposed to be. I recalibrated the PID in the cooler temperature, and it was fine after that.

[mhackney]

Are you using Matter Control? Are you also on a Macintosh? I gave up using MC, it just is too unstable. If you watch the temperature display you will probably see that it is constantly flickering between your set temperature and a temperature 5°C below it. So your hot end is never reaching the set point. I had this happen constantly and it required a reboot of the RAMBo. It is possible that MC was inadvertently triggering something in the firmware. I don't print from the LCD but with Cura, Repetier and OctoPrint the temps are absolutely stable.

[moo77777]

I use Octoprint and it hasn't caused my any problems until now. As for the slicer, I gave up on MatterControl for anything other than laying the piece flat on the build plate and swapped to s3d.

I had this issue because I calibrated in the middle of the summer on a really hot day and the A/C wasn't really stabilized in the room, when the winter came the ambient was a lot cooler at times and the hot end would not get up to where it was supposed to be. I recalibrated the PID in the cooler temperature, and it was fine after that.

How did you go about re-calibrating the PID settings? Is this something you do on the printer itself or settings that get adjusted through firmware?

[mhackney]

I just left the default PID settings that were in the firmware. They are saved to EEPROM and you can auto tune PID on Repetier and save them to EEPROM. But the default settings are pretty darned good. I can't imagine much if any improvement would be gained.

[iKeyborg]

Since one of the latest updates I see hotend temperature is not stable and below set point by 5 - 10C. I found that in 0.92.2 firmware PID numbers are not optimal. For printer RM V3
Kp = 14.5, Ki = 0.73, Kd = 53.4

PID autotune new numbers:
Kp = 55.7, Ki = 11.8, Kd = 65.5

After writing it to EPROM hotend temperature transition and stability are perfect.

Why the firmware has numbers way off the optimal? My be I am missing something?