Heater faults with 1.15c

Having further issues with PID tuning ...

I tried multiple times to do a hot-end tuning with no success.

I have a 40W heater (original that came with the E3D V6) and a 19V power supply. The heater block is isolated with ceramic pad and kapton tape. With 100% PID I reach 240° in about 30 seconds or even less.

Now, I tried tuning with M303 H1 P0.15 S240 and sometimes I reach 240° and it cancels, and sometimes it says "Auto tune of heater 1 failed due to bad curve fit (G=1529.0, tc=208.9, td=3.2)"
If I go lower than P0.15 it always gives the "Bad curve fit" error. If I go above P0.15 it always cancels due to reaching limit temp.

Tried with both 1.15c and 1.15d.

Any thoughts ?

Thanks.

Edit: My temp curve is looking really smooth with no spikes. Don't think I have any issues on that.

Edited 1 time(s). Last edit at 09/28/2016 04:20AM by unromeo21.

Your heater is over-powered. The E3D heaters are rated at 12V or 24V depending on what you order. If you are using a 40W 12V one on 19V, it will generate 100W, which is far too much. The "bad curve" fit message is produced if the gain is more than 1500 - which implies that your hot end would heat to around 1500C if left on at full power.

For safety reasons, I strongly recommend that you get a lower-powered heater. A 24V 40W heater would generate 25W @ 19V, and a 12V 25W heater would generate 62W. You might want to consider using a 24V PSU instead of a 19V one, it will make heaters, fans etc. easier to obtain.

For now you could try plugging those values obtained from tuning into M307, but instead of 1529 for the A value, use 1499.9.

Edited 1 time(s). Last edit at 09/28/2016 12:47PM by dc42.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

First couple of days the printer has been fine. But tonight the first print failed when the heated bed reported an open circuit fault (even though the dwc/graph showed the temperature etc fine) and the second print reported "Error: heating fault on heater 0, temperature excursion exceeded 10.0C" Both errors occurred within the first 5 minutes after the print started.

---

DC42 Kossel 330mm x 2meters
My Thingiverse Creations

Quote
dc42
Your heater is over-powered. The E3D heaters are rated at 12V or 24V depending on what you order. If you are using a 40W 12V one on 19V, it will generate 100W, which is far too much. The "bad curve" fit message is produced if the gain is more than 1500 - which implies that your hot end would heat to around 1500C if left on at full power.

For safety reasons, I strongly recommend that you get a lower-powered heater. A 24V 40W heater would generate 25W @ 19V, and a 12V 25W heater would generate 62W. You might want to consider using a 24V PSU instead of a 19V one, it will make heaters, fans etc. easier to obtain.

For now you could try plugging those values obtained from tuning into M307, but instead of 1529 for the A value, use 1499.9.

Yes, it's a 12V 40W heater. On the 1.14 firmware I reduced the PWM to 0.6 so I had no issues with the 19V power supply. Never really thought of what could happen if somehow the MOSFET would stuck in the ON state. I have for now added the values in the config with a maxpwm of 0.4 and it seems to work really stable withing 0.2°C.
I have noticed that the "new" PID routine in the 1.15 together with the tuning feature is managing the temperatures a lot better than the "old" PID in the previous version.
Now, I like this 19V laptop power supply (at about 6.5 Amps). Small, compact, noiseless.. I wouldn't want to change it. Maybe I will add a second voltage rail for 12V using a voltage converter to feed the hot-end and the fans.

As a funny side note: I just added bed compensation yesterday, and after finishing everything and successfully done a 5 point leveling, out of the sudden, I hear strange creaking noises when was jogging the x y axis. I just couldn't understand from where the hell my stiff printer started to flex and produce these "door creaking noises" like an old barn door. It was not coming from the belts and idles, not from linear motion, not from frame.. than I finally found it.. it was coming from the Z stepper that compensated for the 0.05mm bed skew. I couldn't even see the lead-screw rotating in the first place, I was only hearing the few microstepps it was moving.

By the way, is there an option to use two different bed.g files ? I sometimes use smaller glass sheets on top of the aluminium bed and would like to have a separate leveling routing for that size of glass. The only thing I can come up right now would be to create a macro with everything needed inside. Is this the right way ?

Edited 1 time(s). Last edit at 09/29/2016 06:04AM by unromeo21.

Quote
unromeo21
By the way, is there an option to use two different bed.g files ? I sometimes use smaller glass sheets on top of the aluminium bed and would like to have a separate leveling routing for that size of glass. The only thing I can come up right now would be to create a macro with everything needed inside. Is this the right way ?

Yes. The only special thing about bed.g is that it is run in response to G32. So you can create additional versions of it and invoke them as macros instead of via G32.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Please can we have the option to disable the safety checks. After several days of printing I get random errors on the bed heater or the hot end which go un noticed for a while as the printer keeps printing in the air but wrecking a meter of a filament each time as the extruder can't push it through a cold hot end.

---

DC42 Kossel 330mm x 2meters
My Thingiverse Creations

Quote
DADIY
Please can we have the option to disable the safety checks. After several days of printing I get random errors on the bed heater or the hot end which go un noticed for a while as the printer keeps printing in the air but wrecking a meter of a filament each time as the extruder can't push it through a cold hot end.

I'd like this option too, or at least have the print pause.