AD957 thermocouple compatibility
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Hi all,
I recently bought a Duet 2 Wifi board in order to replace the original board that came with my delta printer. The extruder uses a type k thermocouple with an AD957 amplifier. Is it possible to wire it directly to the Duet 2 Wifi? If so, what are the configurations you are suggesting?
Thank you -
@maxvi8 To connect a thermocouple to the Duet you'll need the thermocouple daughterboard: https://www.duet3d.com/DuetAddons/TC_K_DaughterBoard
Duet only supports MAX31855 or MAX31856, so I don't think you can use any other thermocouple amplifier. Also, I can't find any information about AD957 amplifier. Are you sure it's not something like this? https://learn.adafruit.com/ad8495-thermocouple-amplifier
See also:
https://forum.duet3d.com/topic/3126/is-it-possible-to-connect-ad8495-with-thermocouple-to-duet-0-85
https://duet3d.dozuki.com/Wiki/Connecting_thermocouples#Section_HardwareIan
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You could possibly constrain the output of the amplifier to not exceed 3.3V and then feed it into an analog input configured to use the Linear Analog type of temperature sensor; but it would be significantly less accurate than using the thermocouple board.
Is the thermocouple encapsulated in a standard 3mm cartridge? If so then you might consider replacing it by a PT1000 sensor instead.
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Thank you for the detailed answers.
I read a lot in this forum and in the wiki and I convinced myself to replace the original thermocouple with a 3mm cartridge PT1000. I need to modify a little bit the hardware of the extruder but it's doable and I think that it'll be a nice improvement over the old thermocouple + AD597 amplifier.
Thank you all again!