bed heating issue on a new bed

[sunkenbier]

I just upgraded from a semecnc v3 heated bed to the v10. I have had issues with the bed holding temperatures over 70c. I tuned the bed successfully and saved it:

Heater 0 model: gain 70.7, time constant 452.2, dead time 23.6, max PWM 1.00, calibration voltage 12.2, mode PID, inverted no, frequency default
Computed PID parameters for setpoint change: P48.3, I0.467, D799.2
Computed PID parameters for load change: P4

I tuned the bed a second time successfully and saved it.

Heater 0 model: gain 82.8, time constant 491.4, dead time 11.0, max PWM 1.00, calibration voltage 12.2, mode PID, inverted no, frequency default
Computed PID parameters for setpoint change: P96.5, I1.314, D741.9
Computed PID parameters for load change: P9

When heating the bed to 90 I receive the below issue error:
Error: Heating fault on heater 0, temperature rising much more slowly than the expected 0.0°C/sec

Sometimes this happens within 10 min of the print job, other times it is when the bed is heating up to print. It is not consistant but has not made it farther than 10 min.

Would this be a hardware issue or is there something Im missing in ensuring the duet is configured properly for the bed.

[sunkenbier]

As a note. I am running the most current duet firmware.
I have also tried increasing the dead time without success.

[Flo]

Have you tried to input the information in a M307 command in config.g?
I’ve had the same issue with one of my printers heaters until I composed the M307 from the autotune result, as it was not reading the values from config-override.g

[dc42]

Is the bed actually capable of reaching 90C when run at full power, with the print cooling fan on?

[sunkenbier]

@dc42 I know with my v3 I was able to hit 110c during prints. I normally ran it at 90 so I would imagine the v10 would be able to achieve the same results. The seemecnc site does not say what temp it should be able to hit but during the tuning it hit 90c

[sunkenbier]

@flo Ill try manipulating the config.g. I had been making the modifications to the config-overide.g when I made changes in testing

[dc42]

@sunkenbier said in bed heating issue on a new bed:

When heating the bed to 90 I receive the below issue error:
Error: Heating fault on heater 0, temperature rising much more slowly than the expected 0.0°C/sec

That message suggests that the bed temperature was below 90C but the temperature was not rising. it could be that your print cooling fan makes the difference between the bed reaching 90C and not. You could try tuning the bed heater with the effector lowered and the fan running.

[sunkenbier]

@dc42 As a test I heated the bed with no fans running and just the bed heated at 90c. It hit the 90c and held it for about 10 minutes. There were no spikes in the heat graph but then the temp just stopped heating which resulted in the below error.

8:12:16 AM
M140 S90
8:29:04 AM
Error: Heating fault on heater 0, temperature excursion exceeded 15.0°C

[dc42]

@sunkenbier said in bed heating issue on a new bed:

@dc42 As a test I heated the bed with no fans running and just the bed heated at 90c. It hit the 90c and held it for about 10 minutes. There were no spikes in the heat graph but then the temp just stopped heating which resulted in the below error.

8:12:16 AM
M140 S90
8:29:04 AM
Error: Heating fault on heater 0, temperature excursion exceeded 15.0°C

Strange, I don't see how that error can occur without the temperature deviating from 90C by at least 15C for a few seconds.

[sunkenbier]

@dc42 said in bed heating issue on a new bed:

@sunkenbier said in bed heating issue on a new bed:

@dc42 As a test I heated the bed with no fans running and just the bed heated at 90c. It hit the 90c and held it for about 10 minutes. There were no spikes in the heat graph but then the temp just stopped heating which resulted in the below error.

8:12:16 AM
M140 S90
8:29:04 AM
Error: Heating fault on heater 0, temperature excursion exceeded 15.0°C

Strange, I don't see how that error can occur without the temperature deviating from 90C by at least 15C for a few seconds.

Although the display showed the heater status as active, the temperature just dropped as if it were turned off. It was not a sudden drop. It slowly just dropped down from 90 into the 70s over a minute or two

That's why I'm having such a hard time trouble shooting this. The errors seem so strange to me.

[dc42]

@sunkenbier said in bed heating issue on a new bed:

@dc42 said in bed heating issue on a new bed:

@sunkenbier said in bed heating issue on a new bed:
Although the display showed the heater status as active, the temperature just dropped as if it were turned off. It was not a sudden drop. It slowly just dropped down from 90 into the 70s over a minute or two

Did the temperature start to drop at the same time that the error message appeared, or before it?

[sunkenbier]

@dc42 Temp dropped before the error. Message came up when it drop to 75.

[dc42]

So something caused heating to stop, perhaps a bad connection. I suggest you check the bed heater connections, in particular check that the screws in the bed heater output terminal block are still tight.

Another possibility is that the power supply overheated and reduced its output voltage. If it happens again, run M122 and check the max and min VIN voltages in the report.