I cannot figure out why neither of my temperature sensors read anything other than zero. One is a thermocouple with the MAX31855 interface, the other is a 10k thermistor connected to P0.24.
Tests so far:
Thermistor pins are sitting at 2.5V, about right for a 10k thermistor at room temp (20C)
SPI interface to the MAX31855 seems to be doing all the right things - clock and chip select are running, and data is coming back on the MISO pin (SPI 0)
So it looks like the hardware is behaving properly.
Firmware has been updated to this “upstreamedge-b6153da, Build date: Jun 21 2017 21:02:36” as reported in the console.
Configuration file based on the delta config file example linked to the the smoothie docs.
using the console…
‘get temp bed’ returns ‘bed temp: nan/0.000000 @0’
‘get temp hotend’ returns ‘hotend temp: inf/0.000000 @0’
Does anyone have any idea what might be going on? I’ve hit a brick wall.
My config file:
{board software wont let me post it}
Imported from wikidot
Ok, fix the thermistor by specifying an R-T curve. Still stuck with nonsense on the thermocouple.
Can’t get the bed heater to turn on either, but thats another problem.
Should have also mentioned this is V1.0 hardware. Its taken me a long time to get around to actually using this board.
Make sure you use the very latest version of the edge firmware and config from the wiki. Ideally use M105 to get the temps when debugging. Thermocopules should work, can you try checking the wiring, and maybe try another thermocouple board ?
Seems to be magically working this morning. Re-flashed the same firmware ( only 2 months old), using the same config file as yesterday. Only change was a few extra spaces in this config line : ‘temperature_control.hotend.sensor max31855’ which I added to make it line up with the other text.
Weird. I hope it keeps on working - it bothers me not knowing why it wasn’t working previously.
And now i know. Non-insulated thermocouple + max31855 + intermittent heater block grounding via the chassis. Max31855 gets upset by this.
Switching to the AD8495 analogue thermocouple amp, which can handle grounded tip thermocouples.