Pointerface temperature readings

Hey all, I'm new here and building a Huxley.
I've been having problems with the commissioning phase.
In Pointerface it's at max temperature when the reading is -273 deg C
but i have a reading for my bed (at room temp) at -32 deg C and my extruder at 20 deg C
juat wondering if anyone could help. thanks

Edited 1 time(s). Last edit at 09/29/2013 03:36PM by DuncanW.

Each kind of thermistor has a thermistor table, but i expect that if you bought it as a set, the firmware already contains the matching table. Note that these thermistors are used to control the heating, so it may make the temperature way too hot if you turn it on with a wrong setting.(it has molten carriages, PEEK of a j-head has a max temperature etc.) I think -32C hot end and 20C bed is a too big discrepancy..

Thermistors work by measuring their resistance, so a short/disconnect affects it. (Disconnects usually trigger MINTEMP and shuts off the machine)

Dont know what you mean with 'maximum temperature', i dont think pronterface has such setting, the printer does, at least for the hot end though, looking it up, M143 sets it. If that is -273, it should fail to start, afaik.

Also, got a link what you're reading for commisioning? This? dont see anything about temperature there.

hello, and thanks for replying.
I shorted the terminals when i saw this and it gave me a max temperature reading @-273 and shut down the Printer
i've been following this:
[www.reprappro.com]
and i did indeed get a kit from reprap pro.
I've looked at various parts of the circuit and there doesn't seem to be an open or short.
when I remove the connections from the terminal (ie make a short) it gives the same reading for the bed.
Thanks for all the help