Hot end won't heat above 220C

[ddpruitt]

I've been beating my head on this for two weeks and I now humbly request help.

Rostock Max v2, Rambo board, stock hot end. I had it working fine with the stock firmware.

What I did: Added there FSR's to get the bed leveling and updated the firmware to v 0.92.3.

What is happening: I set the hot end temp to 225C and the temp will get to 220C and stay there.

Question: What settings in configuration.h do I need to be looking for to control the hot end temp?

After updating the firmware to v 0.92.3 I initially had the issue with the PSU tripping when heating up the bed and hot end. I found the topic http://forum.seemecnc.com/viewtopic.php ... r+Firmware and followed the instructions there, which stopped the PSU from shutting off. Did the PID Tuning several times but for what ever reason the hotend will not go above 220C when set to 225C.

I've compared the configuration.h to the stock configuration from Github and the configuration.h posted by AndyB. I think I have reconciled the differences but this is where I am stuck. This is the first time I've played with updating the firmware and I'm not sure if I'm doing it right.

[BenTheRighteous]

Is it that your hotend maxes out at 220 or it always just hovers 5 below temp?

In other words, if you set it to 235, does it hover at 230?

[ddpruitt]

So I've been leery of trying to set it above 225C, but I did set it to 220C to see if it would get to that temp but it did not. I don't recall the exact temp it went to but I think it was 216 or 218C, definitely not 220C though.

Edit: So setting the temp manually is one thing but when I want to print it never reaches the target set point temperature so the print never starts.

[BenTheRighteous]

My guess is that the D of your hotend PID control is too high. I saw the same thing after my autotunes - the temperature would always just hover below the setpoint. I wind up reducing my D by about 30% and my I by about 10%, then the hotend gets to temp just fine. I recommend trying that.

[mvansomeren]

Agree with Ben. I suddenly developed the problem you described and redid my hotend PID settings and the problem was solved.

[JFettig]

I have found that 30% and 10% helps but going 90% lower on both of those or more made my temperature control much better.

[ddpruitt]

Before making any changes I tried setting the temp to 230C, it got to about 223/224C and stopped.

If I set it to 200C it hits 200C. I tried 210C and it almost got above 200C.

I tried lowering the Kd from 127.98 by 30% to 89.58 and the Ki from 2.98 to 2.69 (10%) but I had the same issue.

If I tried lowering the Kd by 40% to 76.79 I get a "Heater decoupled" message.

I tried changing the HEATER_PWM_SPEED from 2 to 1 but I still got the "Heater decoupled".


This is what I'm using:

Code: Select all

#define RETRACT_DURING_HEATUP true
#define PID_CONTROL_RANGE 20
#define SKIP_M109_IF_WITHIN 2
#define SCALE_PID_TO_MAX 0
#define TEMP_HYSTERESIS 0
#define EXTRUDE_MAXLENGTH 100
#define NUM_TEMPS_USERTHERMISTOR0 28
#define USER_THERMISTORTABLE0  {\
  {1*4,864*8},{21*4,300*8},{25*4,290*8},{29*4,280*8},{33*4,270*8},{39*4,260*8},{46*4,250*8},{54*4,240*8},{64*4,230*8},{75*4,220*8},\
  {90*4,210*8},{107*4,200*8},{128*4,190*8},{154*4,180*8},{184*4,170*8},{221*4,160*8},{265*4,150*8},{316*4,140*8},{375*4,130*8},\
  {441*4,120*8},{513*4,110*8},{588*4,100*8},{734*4,80*8},{856*4,60*8},{938*4,40*8},{986*4,20*8},{1008*4,0*8},{1018*4,-20*8}     }
#define NUM_TEMPS_USERTHERMISTOR1 0
#define USER_THERMISTORTABLE1 {}
#define NUM_TEMPS_USERTHERMISTOR2 0
#define USER_THERMISTORTABLE2 {}
#define USE_GENERIC_THERMISTORTABLE_1
#define GENERIC_THERM1_T0 25
#define GENERIC_THERM1_R0 100000
#define GENERIC_THERM1_BETA 4450
#define GENERIC_THERM1_MIN_TEMP -20
#define GENERIC_THERM1_MAX_TEMP 300
#define GENERIC_THERM1_R1 0
#define GENERIC_THERM1_R2 4700
#define USE_GENERIC_THERMISTORTABLE_2
#define GENERIC_THERM2_T0 25
#define GENERIC_THERM2_R0 100000
#define GENERIC_THERM2_BETA 4367
#define GENERIC_THERM2_MIN_TEMP -20
#define GENERIC_THERM2_MAX_TEMP 300
#define GENERIC_THERM2_R1 0
#define GENERIC_THERM2_R2 4700
#define GENERIC_THERM_VREF 5
#define GENERIC_THERM_NUM_ENTRIES 33
#define HEATER_PWM_SPEED 1

Any thoughts?

[BenTheRighteous]

I have never gotten that message and don't know what it means. That's really strange. I would think if your PID values were really wacky, the worst thing that would happen would be some temperature oscillation.

[Polygonhell]

I have never gotten that message and don't know what it means. That's really strange. I would think if your PID values were really wacky, the worst thing that would happen would be some temperature oscillation.

If your I and D values are massively out of wack, you'll never reach temperature, this is a fairly common issue, and autotune can actually leave you in that state. You can tell if it's the actual issue if say you set the temperature to 180 and it hits 175, then set it to 220 and it hits say 210 then the issue is the PID settings rather than the a problem with the heater, since the hotend exceeded the original apparent temperature limit when the requested temperature was increased.

[BenTheRighteous]

Ok you're right, I phrased that poorly. What I meant was that I'm surprised that the firmware would stop trying to drive the heater if the PID values were way off. Is that a safety feature perhaps?

[ddpruitt]

I found a discussion of "Heater Decoupled" at http://forum.felixprinters.com/viewtopic.php?f=7&t=1093.

From the other forum:

My understanding from the Firmware Extruder.ccp file is that during 'Printer::isPowerOn' it will seek the minimum temperature rise (see attached), which in our case is set in the Configuration.h file parameter:

#define DECOUPLING_TEST_MIN_TEMP_RISE 1

My understanding is that if the reading between the last recorded reading and the new reading is less than 1 degree it reads this as a fault.

Adding EEPROM settings in case I totally missed something:

Code: Select all

<-start
<-Info:Autoleveling enabled
<-Transformation matrix: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000
<-zDistortionCorrection:1
<-Free RAM:882
<-Autoretract:0
<-X:0.00 Y:0.00 Z:0.000 E:0.0000
<-FlowMultiply:100
->M115
<-FIRMWARE_NAME:Repetier_0.92.3 FIRMWARE_URL:https://github.com/repetier/Repetier-Firmware/ PROTOCOL_VERSION:1.0 MACHINE_TYPE:Delta EXTRUDER_COUNT:1 REPETIER_PROTOCOL:3
<-Printed filament:1043.90m Printing time:6 days 17 hours 10 min
->M205
<-EPR:2 75 250000 Baudrate
<-EPR:3 129 1043.902 Filament printed [m]
<-EPR:2 125 580203 Printer active [s]
<-EPR:2 79 1800000 Max. inactive time [ms,0=off]
<-EPR:2 83 0 Stop stepper after inactivity [ms,0=off]
<-EPR:3 11 80.0000 Steps per mm
<-EPR:3 23 300.000 Max. feedrate [mm/s]
<-EPR:3 35 120.000 Homing feedrate [mm/s]
<-EPR:3 39 35.000 Max. jerk [mm/s]
<-EPR:3 133 0.000 X min pos [mm]
<-EPR:3 137 0.000 Y min pos [mm]
<-EPR:3 141 0.000 Z min pos [mm]
<-EPR:3 145 250.000 X max length [mm]
<-EPR:3 149 250.000 Y max length [mm]
<-EPR:3 153 379.575 Z max length [mm]
<-EPR:3 59 1850.000 Acceleration [mm/s^2]
<-EPR:3 71 3000.000 Travel acceleration [mm/s^2]
<-EPR:3 881 269.000 Diagonal rod length [mm]
<-EPR:3 885 129.725 Horizontal rod radius at 0,0 [mm]
<-EPR:3 925 150.000 Max printable radius [mm]
<-EPR:1 891 80 Segments/s for travel
<-EPR:1 889 225 Segments/s for printing
<-EPR:1 893 0 Tower X endstop offset [steps]
<-EPR:1 895 0 Tower Y endstop offset [steps]
<-EPR:1 897 1 Tower Z endstop offset [steps]
<-EPR:3 901 210.000 Alpha A(210):
<-EPR:3 905 330.000 Alpha B(330):
<-EPR:3 909 90.000 Alpha C(90):
<-EPR:3 913 0.000 Delta Radius A(0):
<-EPR:3 917 0.000 Delta Radius B(0):
<-EPR:3 921 0.000 Delta Radius C(0):
<-EPR:3 933 0.000 Corr. diagonal A [mm]
<-EPR:3 937 0.000 Corr. diagonal B [mm]
<-EPR:3 941 0.000 Corr. diagonal C [mm]
<-EPR:3 808 0.400 Z-probe height [mm]
<-EPR:3 929 10.000 Max. z-probe - bed dist. [mm]
<-EPR:3 812 2.000 Z-probe speed [mm/s]
<-EPR:3 840 150.000 Z-probe x-y-speed [mm/s]
<-EPR:3 800 0.000 Z-probe offset x [mm]
<-EPR:3 804 0.000 Z-probe offset y [mm]
<-EPR:3 816 0.000 Z-probe X1
<-EPR:3 820 100.000 Z-probe Y1
<-EPR:3 824 86.600 Z-probe X2
<-EPR:3 828 -50.000 Z-probe Y2
<-EPR:3 832 -86.600 Z-probe X3
<-EPR:3 836 -50.000 Z-probe Y3
<-EPR:0 880 1 Autolevel active (1/0)
<-EPR:3 976 0.000 tanXY Axis Compensation
<-EPR:3 980 0.000 tanYZ Axis Compensation
<-EPR:3 984 0.000 tanXZ Axis Compensation
<-EPR:0 106 1 Bed Heat Manager [0-3]
<-EPR:0 107 255 Bed PID drive max
<-EPR:0 124 80 Bed PID drive min
<-EPR:3 108 52.970 Bed PID P-gain
<-EPR:3 112 1.010 Bed PID I-gain
<-EPR:3 116 692.250 Bed PID D-gain
<-EPR:0 120 255 Bed PID max value [0-255]
<-EPR:3 200 92.400 Extr.1 steps per mm
<-EPR:3 204 100.000 Extr.1 max. feedrate [mm/s]
<-EPR:3 208 45.000 Extr.1 start feedrate [mm/s]
<-EPR:3 212 6500.000 Extr.1 acceleration [mm/s^2]
<-EPR:0 216 3 Extr.1 heat manager [0-3]
<-EPR:0 217 255 Extr.1 PID drive max
<-EPR:0 245 40 Extr.1 PID drive min
<-EPR:3 218 39.0000 Extr.1 PID P-gain/dead-time
<-EPR:3 222 2.9800 Extr.1 PID I-gain
<-EPR:3 226 127.9800 Extr.1 PID D-gain
<-EPR:0 230 255 Extr.1 PID max value [0-255]
<-EPR:2 231 0 Extr.1 X-offset [steps]
<-EPR:2 235 0 Extr.1 Y-offset [steps]
<-EPR:2 290 0 Extr.1 Z-offset [steps]
<-EPR:1 239 3 Extr.1 temp. stabilize time [s]
<-EPR:1 250 150 Extr.1 temp. for retraction when heating [C]
<-EPR:1 252 0 Extr.1 distance to retract when heating [mm]
<-EPR:0 254 255 Extr.1 extruder cooler speed [0-255]

[BenTheRighteous]

I can't imagine that reducing your D value was really what resulted in your Heater Decoupled message. The job of the D parameter is to stop things from heating too quickly, so reducing it should have the opposite effect.

In fact, this morning I was playing with my own hotend and I zeroed out my D value so I'm effectively running just on PI control. The temperature oscillates for maybe 10 seconds after it reaches temperature but after that it holds beautifully.

Maybe you could try the same, just for giggles.

[ddpruitt]

I resolved the issue by reverting back to the stock firmware (0.91).

What I found was I am having an issue with the heater manager EXT0_HEAT_MANAGER in 0.92.3, I had it set to 3 which is the Dead Time controller. When I tried setting it to 0 (bang bang) or 1 (PID Control) the temperatures became erratic and the Heater Decoupled would happen.

I did calculate the dead time following the procedure at http://www.repetier.com/dead-time-control/. As an aside I created a C# script and and Excel file to help with the calculation if anyone is interested.

Heater Decoupled info: http://forum.repetier.com/discussion/13 ... ll-heaters.

I will continue beating on the 0.92.3 firmware until I get it working. For now though I'm going to keep using the stock firmware.

[benjaminhill]

I too am having this issue when printing PETG. I have a Rostock Max v2, E3D All-metal v6 HotEnd. I'm shooting for a rather cool PETG 235C for my print, but it hovers at 220. Surprisingly enough, it didn't kill my print! (which makes me a teeny bit suspicious that maybe it is up to temp but is reading low?)

I recalibrated my PID autotune with "M303 S200" - but then reconsidered and re-ran the autotune with "M303 S220" - because yay hotter.
I also saw that "PID max value" was set to 200. I upped it to 255. No idea what that changes, but yay no limits?
BUT - No change, still hovers 220 to 222.

I'm next going to try the "drop the kD" by 30% and kI by 10%, as soon as my current print finishes or dies.

[DerStig]

try sending a M143 S350. that should set you max possible extruder temp to 350c follow it with a M500 to save it. then see if your extruder will go above 220c

[benjaminhill]

My guess is that the D of your hotend PID control is too high. I saw the same thing after my autotunes - the temperature would always just hover below the setpoint. I wind up reducing my D by about 30% and my I by about 10%, then the hotend gets to temp just fine. I recommend trying that.

Fixed it for me, thank you!