Slow Chamber Heater

wdenker

I have tried everything from 50 to 90000000 for D doesn't help.

wdenker

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A Former User

Having looked closer at the link, its quite possible I should have suggested a larger C value which is the time constant.

Phaedrux

If we can figure out a good means of tuning a chamber heater I'll update these pages

https://duet3d.dozuki.com/Wiki/Connecting_and_configuring_a_chamber_heater
https://duet3d.dozuki.com/Wiki/Tuning_the_heater_temperature_control#main

wdenker

@Phaedrux I increased d and c values without any luck. If I could get a longer time for it to heat it would work. Can't figure out what value changes the temp it expects to change every second. It seems like a combination of values. Would be awesome to be able to insert a parameter and value to select that temp. For example default o think is 1.6 degrees every second. If I could change that by a simple flag like T1.2 would make it ten times easier.

Phaedrux

What firmware version are you running?

dc42

@wdenker, have you run heater tuning on the chamber heater?

mrehorstdmd

@wdenker I have a 500W heater in a 420 l enclosure and managed to get it working - slow. It takes about 20 minutes to heat up to 50C. Here's the relevant stuff from the config.g file:

M141 H2 ; Assign chamber heater to heater 2
M307 H2 A11 C99000 D2000 B1 ; chamber heater operates in bang-bang mode
M305 P2 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for chamber
M143 H2 S60 ; Set temperature limit for chamber to 60C

wdenker

@Phaedrux 2.02

wdenker

@dc42 no it's on an ssr using bang bang. I'm going to add a fan to it to hopefully help move some heat.

A Former User

@wdenker said in Slow Chamber Heater:

bang bang

might work to set the pwm frequency low like 10hz that is/was default for the bed on RRF2, and then use PID.

NitroFreak

i use a 2000w oven heater element and put the thermistor in the airflow. The temp rise is about 2.5°C per second and heats to 90C in under 30 seconds.
I think a fan is essential for distributing the air in the chamber, otherwise no accurate measurement is possible

NitroFreak

Another possibility is to just use bang-bang for the heater. Heat it full time until it is at temp, then switch it off etc

wdenker

@NitroFreak what size breaker are you running it on? I was worried about having too much watts. Between the dual hotend of 80w the bed of 900 watt and another 500 watts for the chamber heater getting close to a max for a 15 amp breaker.

NitroFreak

@wdenker said in Slow Chamber Heater:

@NitroFreak what size breaker are you running it on? I was worried about having too much watts. Between the dual hotend of 80w the bed of 900 watt and another 500 watts for the chamber heater getting close to a max for a 15 amp breaker.

they usually don´t all run at the same time, but i also don´t run a bed heater. The chamber heats up the bed anyway so it doesn´t make sense

dc42

@wdenker said in Slow Chamber Heater:

@Phaedrux I increased d and c values without any luck. If I could get a longer time for it to heat it would work. Can't figure out what value changes the temp it expects to change every second. It seems like a combination of values. Would be awesome to be able to insert a parameter and value to select that temp. For example default o think is 1.6 degrees every second. If I could change that by a simple flag like T1.2 would make it ten times easier.

You probably need to reduce the A value as well as increasing D and C above the default values

Seriously, you should try tuning it, even if you intend to run it in bang-bang mode. You may have to use M307 H2 D60 or D120 first for the tuning to work.

miglo

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