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I've several PID tune ups on the hot end, It normally worked really well. Now it's temperature curve is so erratic, maintains a constant 240 C but can change, erratically, as low as 190 the as high at 260 then back to 240. It does this on a constant basis. To the point where it got so cool it caused a clog.

Here is a pic of my Temp Curve. Can someone please tell me what might be the cause?

Obviously, your PID values are way off. I'm not sure what your process is for tuning them up, so I can't really help much. Is it possible you accidentally swapped a couple of the values?

dsnettleton wrote:Obviously, your PID values are way off. I'm not sure what your process is for tuning them up, so I can't really help much. Is it possible you accidentally swapped a couple of the values?

Could be, but I performed 2 PID tunes after I noticed the problem. I do notice that the PID values in the EEPROM are different from the values I add to the Repetier Firmware through Arduino. Plus I also noticed that in the Repetier host Configure EEPROM it only has PID values for extruder 1.. Am I supposed to change the values of Ext 1 in EEPROM through repetier host?

you need to change the values in eeprom, yes.

whats happening is that eeprom overides firmware settings unless you have eeprom disabled.

cambo3d wrote:you need to change the values in eeprom, yes.

whats happening is that eeprom overides firmware settings unless you have eeprom disabled.

I have it enabled. But the EEPROM settings in Repetier Host for EXT says " EXT1". Shouldn't it be EXT0? Here is a screen shot...

Also, Notice in the "Filament Printed [mm]" field, should that be 1.75, which is what I currently print?

elqisqeyano wrote:

cambo3d wrote:you need to change the values in eeprom, yes.

whats happening is that eeprom overides firmware settings unless you have eeprom disabled.

I have it enabled. But the EEPROM settings in Repetier Host for EXT says " EXT1". Shouldn't it be EXT0? Here is a screen shot...

Also, Notice in the "Filament Printed" field, should that be 1.75, which is what I currently print?

Should I change EXT1 to EXT0?

well if you have eeprom enable then whatever firmware changes you make wont reflect what your eeprom settings are, like i said they override the firmware settings.

cambo3d wrote:well if you have eeprom enable then whatever firmware changes you make wont reflect what your eeprom settings are, like i said they override the firmware settings.

It runs just fine with it set at EXT1 instead of EXT 0, so I won't mess with it.

what i said had nothing to do with your ext 1 or ext 0.

cambo3d wrote:what i said had nothing to do with your ext 1 or ext 0.

Let me rephrase that. I know they override firmware, but the fact that it says Extr 1 in repetier host EEPROM and EXTR 0 in Repetier Firmware it seems to be fine so I will just see what happens. I just finished printing Xnaron's "Effector" piece and it came out really good. Perfectly flat and consistent. So I figured it's OK written that way. Thanks for your help.

no problem, let us know how your mag mod turns out.

Is the temperature erratic like that when the the head is stationary, or only during a print?

Polygonhell wrote:Is the temperature erratic like that when the the head is stationary, or only during a print?

It was only when printing a job, it seems to have settled now. I did a few PID tunes and now seems to hold a good flat line on the temp curve.

Thanks.

cambo3d wrote:no problem, let us know how your mag mod turns out.

I will definitely post a thread with pics. I am just waiting for my magnets to arrive. I have all the parts all made and received the chrome steel balls. Anxiously awaiting.

elqisqeyano wrote:

Polygonhell wrote:Is the temperature erratic like that when the the head is stationary, or only during a print?

It was only when printing a job, it seems to have settled now. I did a few PID tunes and now seems to hold a good flat line on the temp curve.

Thanks.

Then I'd guess you have a loose connection in the path to the thermistor.

Polygonhell wrote:

elqisqeyano wrote:

Polygonhell wrote:Is the temperature erratic like that when the the head is stationary, or only during a print?

It was only when printing a job, it seems to have settled now. I did a few PID tunes and now seems to hold a good flat line on the temp curve.

Thanks.

Then I'd guess you have a loose connection in the path to the thermistor.

Like a loose wire connection?

elqisqeyano wrote:
Like a loose wire connection?

loose wire, possibly a bad solder joint, or a bad crimp, maybe thermistor loose in the hole.
The issue is probably on the head end of the wiring, there is no way the temperature is changing that fast.
The fact you don't see it when stationary to me implies that the motion is triggering the issue, so most likely something loose or getting close to breaking, and since the head is the moving bit it's most likely near there.

Polygonhell wrote:

elqisqeyano wrote:
Like a loose wire connection?

loose wire, possibly a bad solder joint, or a bad crimp, maybe thermistor loose in the hole.
The issue is probably on the head end of the wiring, there is no way the temperature is changing that fast.
The fact you don't see it when stationary to me implies that the motion is triggering the issue, so most likely something loose or getting close to breaking, and since the head is the moving bit it's most likely near there.

Tnahks, Will dissect thermistor starting at the Hot End and investigate this further. I appreciate your help.

Namaste.