Unstable temperature (Probable auto-tuning problem)

[khondoke]

Hello, I am having problem with my M201 printer. The temperature is not stable. For instance, I set the nozzle temperature at 240C. Then it goes to 256C and go down to 228C, then again goes very high & low. It continues to do that. I kept it open for a longer time to see if it reaches finally at the set point and become relatively stable. But no hope. It continues to fluctuate. I think, it might be an PID auto-tuning problem. Would you please help me to fix the problem and advice me how can I get fairly stable temperature? Do I require the firmware to upload again? If so, please share the firmware with me. I got the system with factory uploaded firmware. Thank you very much.

[William]

Hello, I am having problem with my M201 printer. The temperature is not stable. For instance, I set the nozzle temperature at 240C. Then it goes to 256C and go down to 228C, then again goes very high & low. It continues to do that. I kept it open for a longer time to see if it reaches finally at the set point and become relatively stable. But no hope. It continues to fluctuate. I think, it might be an PID auto-tuning problem. Would you please help me to fix the problem and advice me how can I get fairly stable temperature? Do I require the firmware to upload again? If so, please share the firmware with me. I got the system with factory uploaded firmware. Thank you very much.

I guess you are right, it might be an PID auto-tuning problem.You can upload the latest version 1.0.5 to have a try:
http://www.geeetech.com/forum/viewtopic ... 20&t=17597

[khondoke]

Hi, I have uploaded a new firmware following the step-by-step instruction you posted. Unfortunately, no hope. Still the same problem. I also checked the PID parameters. They are exactly same as previous values. I added the image here. Would you please instruct me any further to fix the problem? Thank you very much.

[William]

Hi, I have uploaded a new firmware following the step-by-step instruction you posted. Unfortunately, no hope. Still the same problem. I also checked the PID parameters. They are exactly same as previous values. I added the image here. Would you please instruct me any further to fix the problem? Thank you very much.

Hi,
You said "I kept it open for a longer time",how long did you wait for?The PID parameters in my printer are the same as yours,and my temp fluctuates about 7-8 degrees,i guess it's normal?BTW,my firmware version is 1.0.4

[khondoke]

Hello, I think if PID values are kept constant then its not auto-tuning. I am trying to use a different extruder system with M201 printer. So, the PID values for this new extruder structure would be different than those of the original extruder came with M201 printer. Would you anyone please help me how can I perform auto-tuning using the M201 firmware so that I can get the optimum PID values corresponding to the new extruder system? I mean, how to do auto-tuning using M201 printer/firmware. Thank you very much.

I again tried with original extruder of M201, and it gives me quite stable temperature with only 1 ~ 2 degrees fluctuation.

[William]

Hello, I think if PID values are kept constant then its not auto-tuning. I am trying to use a different extruder system with M201 printer. So, the PID values for this new extruder structure would be different than those of the original extruder came with M201 printer. Would you anyone please help me how can I perform auto-tuning using the M201 firmware so that I can get the optimum PID values corresponding to the new extruder system? I mean, how to do auto-tuning using M201 printer/firmware. Thank you very much.

I again tried with original extruder of M201, and it gives me quite stable temperature with only 1 ~ 2 degrees fluctuation.

So it is,the extruder come with M201 works fine...As you change a new extruder,the specification of the heater and the thermistor it comes with are not the same with the old one. For GTM32, cause the mainpower is 24V, so the resistance of heating cartridge should be about 12.1ohms and 100 kohms for the thermistor.You can measure yours.
Besides,the GTM32's firmware is not open source,so you only can get some helps from the G-codes,hope the following link will help you:
http://reprap.org/wiki/RepRap