Trouble with heating up using a toolboard

Piet

Dear users,

I'm trying to start printing ASA for which i ran PID tuning at 280C. After some time i got the error that it didn't reach the desired temperature. It only reached about 270ish. This confused me as i have an identical printer, with a different control board (not duet), with the same extruder that can easily reach 300C (and faster too).

To make sure the temperature reading was correct I measured using a thermocouple inside the heater block. The other printer's temperature reading was basically spot on while the duet with a pt1000 was about 15C higher than the actual temperature (maybe i did something wrong here because that seems like alot).

I'm using a duet3 + sbc connected to a toolboard. The PT1000 is connected to temp0, the voltage i measured going to the toolboard is 24V and the voltage to the heater when it's on is ~21.8V. The heater is supposed to be 80W which is correct as i measured 7 Ohms over the heater.

Is this a power issue? The power wiring to the toolboard is 2x0.5mm, i assumed this was thick enough for the 3.3A (should be good to about 5A i thought).

At the moment I'm seeing if there is a difference if i use bangbang instead of PID but that doesn't seem to be the case.

The config of the heater and temperature sensor:

M308 S1 P"20.temp0" Y"pt1000" A"Extruder"				 ; configure sensor 1 as thermistor on pin 20.temp0
M950 H1 C"20.out0" T1                                    ; create nozzle heater output on 20.out0 and map it to sensor 1
;M307 H1 B0 R1.821 C159.8:143.3 D6.60 S1.00 V21.8		 ; disable bang-bang mode for heater  and set PWM limit
M307 H1 B1

Any help would be appreciated!

Piet.

Edit: Just measured the current going to the toolboard and it's only 1.8A. So it makes sense it doesn't heat up very fast as that is only 40W (21.8*1.8). Not sure where the problem lies.

Gixxerfast

@piet
Hi, You don't have one of these in your config?

M143 H1 S280

Btw. Do a m122 B20 for some diagnostics. They usually want that
Btw2, you are taking 24V directly from the PSU I assume
Btw3, I print mainly ASA and I rarely go above 260C, but that's another question

Piet

@gixxerfast I set the max temperature to 300C, forgot to include that.

M143 H1 S300                                             ; set temperature limit for heater 1 to 300C

Btw. Do a m122 B20 for some diagnostics. They usually want that

m122 B20
Diagnostics for board 20:
Duet TOOL1LC rev 1.1 or later firmware version 3.4.0beta5 (2021-10-12 13:59:06)
Bootloader ID: SAMC21 bootloader version 2.3 (2021-01-26b1)
Never used RAM 2484, free system stack 2789 words
Tasks: Move(notifyWait,0.0%,153) HEAT(notifyWait,0.3%,115) CanAsync(notifyWait,0.0%,64) CanRecv(notifyWait,0.0%,77) CanClock(notifyWait,0.0%,64) ACCEL(notifyWait,0.0%,61) TMC(delaying,3.0%,57) MAIN(running,91.8%,350) IDLE(ready,0.0%,27) AIN(delaying,4.9%,142), total 100.0%
Last reset 00:33:35 ago, cause: power up
Last software reset data not available
Driver 0: pos 0, 348.0 steps/mm, standstill, SG min/max 0/0, read errors 0, write errors 0, ifcnt 11, reads 24700, writes 11, timeouts 0, DMA errors 0, steps req 0 done 0
Moves scheduled 0, completed 0, in progress 0, hiccups 0, step errors 0, maxPrep 0, maxOverdue 0, maxInc 0, mcErrs 0, gcmErrs 0
Peak sync jitter 0/5, peak Rx sync delay 215, resyncs 0/0, no step interrupt scheduled
VIN voltage: min 21.6, current 21.6, max 24.4
MCU temperature: min 32.5C, current 49.8C, max 51.8C
Last sensors broadcast 0x00000006 found 2 36 ticks ago, loop time 0
CAN messages queued 41092, send timeouts 0, received 18096, lost 0, free buffers 37, min 37, error reg 0
dup 0, oos 0/0/0/0, bm 0, wbm 0, rxMotionDelay 0
Accelerometer detected: yes, status: 00
I2C bus errors 0, naks 3, other errors 0
=== Filament sensors ===
Interrupt 5726621 to 0us, poll 2 to 773us
Driver 0: no data received

Btw2, you are taking 24V directly from the PSU I assume
Yes

Btw3, I print mainly ASA and I rarely go above 260C, but that's another question
True i was just about to run some temperature testing when I noticed it doesn't reach temperatures it should.

Gixxerfast

@piet You Vin is very low I think.

VIN voltage: min 21.6, current 21.6, max 24.4

I'm going to heat up mine and see. Un momento ...

... This is mine under full heating: VIN voltage: min 23.8, current 23.8, max 23.8

EDIT and now: VIN voltage: min 24.0, current 24.0, max 24.0

Very stable

I also run AWG20 to the toolboard, but maybe you should check the wiring to make sure all is connected as it should. and that you really have thick enough wire 0.5mm2 (double check )

T3P3Tony

@piet said in Trouble with heating up using a toolboard:

Just measured the current going to the toolboard and it's only 1.8A.

was this during a heatup from cold as opposed to when the temperature is close to the set point?

how much current does the heater draw if you connect it (briefly) directly to the power supply. Leave the temp sensor connected to the duet so you can monitor the temperature and cut the power before it gets too high.

Piet

@gixxerfast

You Vin is very low I think.

I noticed this and actually already turned the supply up, that's why there is such a big difference in voltage.

I also run AWG20 to the toolboard, but maybe you should check the wiring to make sure all is connected as it should. and that you really have thick enough wire 0.5mm2 (double check )*

Yup double checked it.

I actually measured the current wrong, it shows 3A now. The voltage across the heater is 22.8V so I'm approximately 10W short. (22.8 * 3 = 68.4W)

Piet

@t3p3tony I'm guessing this was an error on my part, see my reply to gixxerfast.

how much current does the heater draw if you connect it (briefly) directly to the power supply. Leave the temp sensor connected to the duet so you can monitor the temperature and cut the power before it gets too high.

I'm going to try this now.

Piet

@t3p3tony

how much current does the heater draw if you connect it (briefly) directly to the power supply. Leave the temp sensor connected to the duet so you can monitor the temperature and cut the power before it gets too high.

I attached the heater to a seperate 24V supply. It draws 3.33A and it gets up to, albeit pretty slow, to 300C. However measuring using the thermocouple it only gets to about 285C.

T3P3Tony

@piet what sort of heating element/heater block is it? 80W should get higher than 300 for sure in a "normal" v6/volcano/slice style heater block unless there is a lot of heat escaping/being removed.

Piet

@t3p3tony It's an 80W heater with a custom heater block about the size of a supervolcano and full aluminium. It's not insulated so it probably is losing quite a bit of heat, I'm going to look into that in the future.
However regarding this issue. It seems the toolboard is limiting the amount of current for some reason if I'm thinking correctly. Do you agree or should I look elsewhere?

T3P3Tony

@piet to rule out a physical problem with the toolboard please do the following test:

Set the heater fault timeout to longer than it took the hotend to heat to 300 when plugged directly into the power supply, also allow a larger window. M570 H1 Pnnnn T30 where nnnn is time in seconds.
Set the max temperature allowed to 310 to allow you to test all the way to 300: M143 H1 S310

Command the heater to 300 and measure the current drawn. At least until the temperature gets close to the setpoint it should be similar to that when plugged in directly.

Note these settings are not intended to be for normal use, just for this test.

There are losses in the system of course, along the wires to the toolboards. the mosfets on the toolboard and the wires to the heater but the system should be able to work with a 80W heater at 24V.