Cyclops hot end won't hold temperature, even with PID tuning

[626Pilot]

I've tried crazy high P-values (500+), but with the part cooling fans on, the hot end just won't hold temperature. It can never reach 220C, is lucky to hold 210C, and usually slides down to 205C, and at that point the controller throws a heating fault. These fans aren't all that powerful - they're weaker than the ones SeeMeCNC sells. I never had this problem with Smoothie. What gives?

m573 p1 (show extruder PWM) shows that heater 1's average PWM is 1.0. Does this mean that this board is incapable of supplying enough current to run part cooling with a Cyclops, even with these weak fans?

[IMBoring25]

It doesn't seem like that should be an issue if nothing else has changed. Did you perform an ADC calibration as described at http://forums.reprap.org/read.php?340,326029 ? I wonder if it's indicating low...

[bot]

Are your temps accurate? I had to crank my beta value for the e3d thermistor to 4650 to get comparable temps to my Rambo with the thermistor table for the same thermistor.

[Eaglezsoar]

Is there anyway that you could wrap the heat block with the self fusing silicone tape to insulate it?

[JFettig]

What are your I and D values?

Try P=40, I=.1, D=.1

If it overshoots big, reduce P, if it takes a while to get past the last 80%, make P bigger.

[626Pilot]

It doesn't seem like that should be an issue if nothing else has changed. Did you perform an ADC calibration as described at http://forums.reprap.org/read.php?340,326029 ? I wonder if it's indicating low...

Ah, this is cool. I took 100K and 220 ohm resistors, plugged them into F-to-F jumper wires, and hooked them up to the board. Came up with these numbers:

M305 P0 B3974 H-49 L-50
M305 P1 B3974 H-40 L3

However, the hot end is reading 31.1 while the bed reads 24.9. I don't believe it. What beta values are you guys using? That has to be what's wrong. No way there's that kind of gap in temperature. The hot end should read cooler, if anything. It has a fan cooling it all the time.

[IMBoring25]

The one that comes with the v6 is supposed to be 4267.

[626Pilot]

I switched to using 4267 for the E3D thermistor, and 4450 for the Onyx thermistor. That second number doesn't seem to be published anywhere, but I assume it's the first heater as I dig through Configuration.h in SeeMeCNC's Repetier fork.

Wound up with these values:

Code: Select all

M305 P0 T100000 B4450 R4700 H-59 L173	; Put your own H and/or L values here to set the bed thermistor ADC correction
M305 P1 T100000 B4267 R4700 H-56 L105	; Put your own H and/or L values here to set the 1st nozzle thermistor ADC correction

The system seems to read a little different depending on whether there's a thermistor (or test resistor) plugged into either port, so the final values seem to wander by a degree or so. Good enough! The hot end and bed are reading within 1.5C of each other now.

[critical_limit]

@626Pilot:

Have you solved your temp holding problem with running layer fans?

Would you post your config.g line where PIDs are for the hotend?

Have the same with my layer fans and can´t get it holding temp.

thanx

[626Pilot]

; PID
; ----------------------------------------
; Bed
M301 H0 P130 I1 D125 T0.4 S1 W300 B30
; Heater 1
M301 H1 P60 I1 D125 T1.0 S1 W300 B30

I can't test the fans right now because a print is running. The Duet panel and web interfaces have no fan control, and if I fire up Repetier Host it'll screw up the print for sure.

[bot]

The web interface has a fan control if you enable it in the settings part. Also, the paneldue has a fan control on the "print" page. It uses the same value as the firmware (unless you have the beta paneldue build) so 0 is off, 1 is on, 0.5 is 50% OR 0-255

[JFettig]

Your D value is so high it freaks out every time temperature goes up a little bit.