Dual Thermistor setup

Killernoy

Same Setup as mentioned here: https://forum.duet3d.com/topic/13237/pid-tuning-edge-temperature-ac-bed-heater?_=1576521159573
600 * 600 * 6 mm Aluminium Plate with 500 * 500 mm 1500W AC Heater and two temperature sensors: one within the silicon heatpad and one at the edge of the Aluminium Plate.

Now my question is:
Can I create a custom heating procedure that would raise the temperature read from the sensor within the heater to 10 degrees, above the set temperature than wait till the second sensor reaches the set temperature and after that cool down to the set temperature?

It should be dynamic like so:
Phase 1: T1 heats up to X+10 degrees
Phase 2: wait till T2=X
Phase 3: Cool down till T1=X
(X=temperature set by "M140 S (X) ")

The Goal is to get a more even temperature over the entire Bed.

dc42

I haven't tried it, but I think you could do it with RRF3. Configure the heater and sensor 1 as normal. Configure a dummy heater using sensor 2. Something like this:

M308 S0 <sensor 0 parameters>
M308 S1 <sensor 1 parameters>
M950 H0 C"bedheat" T0 ; the real bed heater
M950 H1 C"e6heat" T1 ; the dummy bed heater
M140 H0:1
M140 S80:0
M116
M140 S80:70
M116
M140 S70:70
M116

This won't work if T2 reaches X before T1 reaches X+10.

jens55

Wouldn't this be easy as pie with the new decision logic that is coming ?

dc42

@jens55 said in Dual Thermistor setup:

Wouldn't this be easy as pie with the new decision logic that is coming ?

Probably.

Killernoy

Thanks for the fast reply.
Since there is a distance of about 50mm between the heater and the edge sensor this should work.

Is there an automatic conversion tool from V2.03 to RRF3?

dc42

@Killernoy said in Dual Thermistor setup:

Thanks for the fast reply.
Since there is a distance of about 50mm between the heater and the edge sensor this should work.

Is there an automatic conversion tool from V2.03 to RRF3?

No, it's manual. https://duet3d.dozuki.com/Wiki/RepRapFirmware_3_overview#Section_Summary_of_what_you_need_to_do_to_convert_your_configuration_and_other_files

Killernoy

@dc42 I only need to edit the "x".g Files and not the .json or the Backup of the config.g right

dc42

@Killernoy said in Dual Thermistor setup:

@dc42 I only need to edit the "x".g Files and not the .json or the Backup of the config.g right

Correct, the json file is only used by the online config tool.

Killernoy

@dc42 thanks again
I will have to wait for new dupont connectors to arrive, in order to extend the sensor wire, after that i will let you know if your code worked or not.

Killernoy

@dc42 said in Dual Thermistor setup:

I haven't tried it, but I think you could do it with RRF3. Configure the heater and sensor 1 as normal. Configure a dummy heater using sensor 2. Something like this:

M308 S0 <sensor 0 parameters>
M308 S1 <sensor 1 parameters>
M950 H0 C"bedheat" T0 ; the real bed heater
M950 H1 C"e6heat" T1 ; the dummy bed heater
M140 H0:1
M140 S80:0
M116
M140 S80:70
M116
M140 S70:70
M116

This won't work if T2 reaches X before T1 reaches X+10.

Since I had that accident were my Hotend melted(https://forum.duet3d.com/topic/13380/why-did-my-printer-melt), I want to get this right:

Does e6heat = !duex.e6heat
or e6heat = !duex.e5heat
or neither of the above?

Killernoy

@dc42 I have added this to my config.g but the temperature of the dummy heater is not showing up neither in the web control nor thru M105
M308 S5 P"duex.e4temp" Y"thermistor" T100000 B4138 ; configure sensor 5 as thermistor on pin duex.e4temp
M950 H5 C"e6heat" T5 ; create Dummy heater and map it to sensor 4

Killernoy

I have also Tested this
M308 S5
Sensor 5 type Thermistor using pin (e4temp,duex.e4temp,exp.thermistor5,exp.37), reading 40.5, last error: sensor not ready, T:100000.0 B:4138.0 C:0.00e+0 R:4700.0 L:0 H:0