Add two more temperature sensors

dc42

@jay_s_uk said in Add two more temperature sensors:

@the_dragonlord you can buy a daughterboard and use either PT100 or type K thermocouples.
Although the pins are available for the extra temperature sensors on the expansion header, they don't have the required hardware, so a duex2 or duex5 is required.
You could always have a go at adding the bits required of course.

The only extra bits required are a 2K2 or 4K7 1% or better resistor between each temperature input in use and the VREF pin. Connect the thermistor between the temperature input and VSSA.

A Former User

@dc42 sorry but I'm not so expert, could you please give me a scheme? The thermistors have 2 pins so I don't understand...

Once I plug the two thermistors what GCODE should I use to make them "work" and be able to see the temperatures in the PanelDue and in the DWC?

jay_s_uk

@the_dragonlord The schematic can be found here https://github.com/Duet3D/Duet-2-Hardware/tree/master/Duet2/Duet2v1.04
You would then map them as you would a temperature sensor on a duex.

A Former User

@jay_s_uk said in Add two more temperature sensors:

@the_dragonlord The schematic can be found here https://github.com/Duet3D/Duet-2-Hardware/tree/master/Duet2/Duet2v1.04
You would then map them as you would a temperature sensor on a duex.

Excellent thanks! Do you know how to connect the thermistors and the resistors to the board as suggested by @dc42 ? I'm not sure...should I add a themistor pin to +V (12VDC or 5VDC or 3VDC in case?) using a thermistor and the other thermistor pin to the chosen board pin? After that should I use the M308?

jay_s_uk

@the_dragonlord if you look at this part of the schematic

you can see that the 4k7 resistors are between ADVREF and the thermistor input.
This is available on the expansion port header

You then connect the thermistor between VSSA and the thermistor input as with the other connections

A Former User

@jay_s_uk said in Add two more temperature sensors:

@the_dragonlord if you look at this part of the schematic

you can see that the 4k7 resistors are between ADVREF and the thermistor input.
This is available on the expansion port header

You then connect the thermistor between VSSA and the thermistor input as with the other connections

Uh ok, so I plug the first thermistor pin to ADVREF using the resistor and to the THERMISTORx pin in the expansion connector and the other thermstor pin to the VSSA pin in the expansion connector, right?

jay_s_uk

@the_dragonlord yes

A Former User

@jay_s_uk excellent! thanks a lot!

A Former User

@jay_s_uk said in Add two more temperature sensors:

@the_dragonlord yes

I there a way to see the temperatures in my PanelDue? I know what to do in DWC but not with the display...

jay_s_uk

@the_dragonlord That is a good question.
I don't know whether its supported.
If it isn't maybe @mfs12 can add it as a feature request

A Former User

@jay_s_uk said in Add two more temperature sensors:

@the_dragonlord That is a good question.
I don't know whether its supported.
If it isn't maybe @mfs12 can add it as a feature request

it would be great! Another question: in the schematics all the resistors are "named" with a tollerance of 0,1%. Is this a mistake? Maybe they meant 1%?

jay_s_uk

@the_dragonlord 0.1% in SMD are easy to come by
https://uk.farnell.com/panasonic/era-2veb4701x/res-4k7-0-1-0-063w-0402-thin-film/dp/3482118

A Former User

@jay_s_uk said in Add two more temperature sensors:

@the_dragonlord 0.1% in SMD are easy to come by
https://uk.farnell.com/panasonic/era-2veb4701x/res-4k7-0-1-0-063w-0402-thin-film/dp/3482118

Uh, yes.....I already have a lot of 1% resistors (I'm pretty sure to have 4,7K) can I use them instead of 0,1%? The temperature read I need doesn't have to be soooooooooo accurate, I need to have just something more than a temperature indication to know if my cooling system is doing its job well or if there's an "alarm"....

jay_s_uk

@the_dragonlord to quote dc42

The only extra bits required are a 2K2 or 4K7 1% or better resistor

A Former User

@jay_s_uk said in Add two more temperature sensors:

@the_dragonlord to quote dc42

The only extra bits required are a 2K2 or 4K7 1% or better resistor

you're right, I forgot what @dc42 said....I apologize...thanks for all the precious hints!

jay_s_uk

@the_dragonlord no need to apologise. Good luck!

dc42

We use 0.1% tolerance resistors because greater precision is needed when using PT1000 sensors. But for thermistors, 1% should be good enough.

A Former User

@dc42 Thanks to both of you guys, you are a real source of knwoledge! I'm learning a lot of things and, I have to be honest, I'm having a lot of fun making mods to my printer using this amazing board! If I think of all the time I've wasted in the past using marlin-based boards.....well, Duet is another world!