Heated chamber

Hi.

I'm looking to deal with ABS warping issues on my corexy so have started enclosing my build chamber and hopefully the heated bed will reasonably maintain the chamber temperature. I want to use the expansion header to monitor the temperature in my heated chamber. I plan to simply attach a thermistor between the AD7 and ground pins on the header (it's a duet 0.6). Is this correct or do I need anything else on the hardware side? Further, on the software side how do I assign this thermistor as the heated chamber monitor so that it shows up on the web interface and can be used to control a chamber heater if required later?

Thanks in advance.

AD7 is a good choice, because that's what the DueX4 expansion board uses to connect the E1 thermistor. Connect the thermistor between VSSA and AD7, with a capacitor in parallel with it (the Duet and DueX4 use 10uF, but lower should be OK). Also connect a 4.7K 1% resistor between AD7 and +3.3V. To assign the channel in firmware, see [reprap.org]. You can pick up VSSA from one of the existing thermistor input terminals.

Edited 1 time(s). Last edit at 03/18/2016 04:50PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks for the clear instructions David. Made a little circuit for this and it just worked. Enclosed my build chamber too and it stays a toasty 53C with a 100C heated bed. No additional heating needed. It's comforting to know that the duet can control an external Mosfet/ SSR to get an even higher temp if required.

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Enclosed my build chamber too and it stays a toasty 53C with a 100C heated bed.

what materials for the enclosure?

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Delta Printer
Duet 0.8.5 firmware 1.19

The printer is built in a plywood box so that takes care of the bottom and 3 sides. Made a hood with 2 plies of thick plastic bags. And a 'door' with 2 plies of corrugated cardboard held on with magnets for easy removal. The pics make it clear.