Unsolved Unable to use chamber heater unfinite
-
Hello. I would like to run the chamber heater infinite, is it possible? The chamber is to big for the heater to reach max temp. I run the heater with SSR and 230v. I get a error message after a few seconds with the heater on: Error: Heater 2 fault: temperature rising much more slowly than the expected 1.8°C/sec
Why do i get this with bang-bang enabled? I though it was monitoring only with PID.; Chamber heater
M308 S2 P"e1temp" Y"thermistor" T100000 B3950 ; configure sensor 2 as thermistor on pin e1temp
M950 H2 C"e1heat" T2 ; create chamber heater output on e1heat and map it to sensor 2
M143 H2 S80 ; set temperature limit for heater 2 to 80C
M307 H2 B1 ; enable bang-bang mode for the chamber heater
M141 H2 ; map chamber to heater 2Please ask if more info is needed.
-
Did You run PID tuning ?
OK, Did noticed bang-bang mode. But I would set PID, and run autotune.
-
As BoA says you'll need to either PID auto tune the heater to give the firmware an idea of how it performs, or you'll have to derive your own PID values manually. Chamber heaters have a slow heat up time so you may need to increase the dead time.
https://duet3d.dozuki.com/Wiki/Tuning_the_heater_temperature_control
https://duet3d.dozuki.com/Wiki/Connecting_and_configuring_a_chamber_heater
-
Also, if the printer is fully enclosed, adding fan blowing through heater might help a little to dissipate heat from heater to chamber air. And heater itself will work on lower temps which would make it to live longer
-
I did not look in to this until now. I get this message when i try to run PID "Auto tune cancelled because temperature is not increasing"
Thats because the enclosure is very big. I would like to set the parameters manually, but I don't understand how it works.
This is from Dozuki:
"Setting the model parameters manuallyModel parameters can be changed and reported using the M307 command. Examples:
M307 H1 A350 C139 D5.5 B0 ; set model parameters for heater 1 and use PID mode
M307 H1 ; report model parameters for heater 1, and whether the model is being used
The H parameter specifies the heater.
The A parameter is the model gain, which is the ultimate temperature rise divided by the PWM fraction. For example, a gain of 350 means that at a constant 50% PWM, the temperature would eventually reach ambient temperature plus 350 * 0.5 degC.
The D parameter is the dead time, which is the delay between a change in PWM and an appreciable effect on the rate of temperature change.
The C parameter is the model time constant. This may be thought of as the time taken for the temperature rise to reach 63.2% of its ultimate value after the heater is switched on from cold at constant PWM, less the dead time.
You can limit the PWM by adding a suitable S parameter, for example S0.8 will limit the PWM to 80%.
To use bang-bang mode instead of PID, change B0 to B1. In bang-bang mode, the S parameter is still used to limit the PWM when the heater is turned on."
Does anyone know how to do this with a chamber heater?
-
Things that come to my mind:
- you can try use 100% (no PWM "dimming...") if it already is not sufficient now
- you can have a big heater (more Watt e.g.)
- you can try to insulate your enclosure to keep the heat in (and use a fan for cooling if it gets too hot)
...
Can you post more details about your printer hardware setup specs (and pictures) for more forum-users to better understand your setup now and what you are trying to achive?
-
First see if you can get PID auto tune to work by increasing the dead time value.
If auto tuning fails with a message that the temperature is not rising fast enough, this indicates that either you are using too low a P value in the M303 command, or the dead time in the existing model is much too low for your heater. You can increase the dead time using the M307 command. For example, sending M307 H0 D30 will increase the dead time to 30 seconds. The actual dead time will be known after a successful auto tuning.
In your case you could try increasing the dead time even more than 30 seconds. Try a few minutes even.
-
@Quattro If You want to run it constantly - just use output pin as 1/0 and controll it as an io pin, not as a heater.
How big is Your chamber, and what is the heater power? Is the heater ventilated somehow?
Adding a fan that blows air through the heater might help to dissipate the heat and equalize air temperature in chamber.
