Duet 6XD Thermocouple Daughterboard Issue

Hardware_SortingRobotics

I have been trying to get a brand new thermocouple daughterboard to work on my also brand-new Duet 3 6XD. Unfortunately, I have not been able to get the board to read temperatures, or output any readings at all.

We have tried many different configurations in firmware. This is the current config we have set up. We have verified that the MAX3185 chip is the one that is installed on this thermistor daughter board.

M308 S4 P"spi.cs0" Y"thermocouple-max31855" F60 ; configure sensor as thermocpuple
M950 H5 C"out6" T5                            ; create nozzle heater output and map it to sensor
M307 H5 B0 S1.00                              ; disable bang-bang mode for heater  and set PWM limit
M143 H5 S275                                  ; set temperature limit for heater
M563 P5 S"Thermocouple (No Heater)" H5 F0     ; define tool
G10 P5 R0 S0                                  ; set initial tool active and standby temperatures to 0C

When this config file is used, this is the result on the web interface:

This is the most common outcome as we reconfigure the firmware. There are some circumstances where the temperature shows up as "2000C" instead, usually when using another spi port.

Please let me know if there is any advice you could give to us.

gloomyandy

@Hardware_SortingRobotics said in Duet 6XD Thermocouple Daughterboard Issue:

M950 H5 C"out6" T5

Shouldn't that be T4 to use the sensor you have just created using M308?

Hardware_SortingRobotics

@gloomyandy Yes this is true. I copied and pasted this code into the post sloppily and must have mixed these up. The problem persists even when the heater/sensor numbers match.

Hardware_SortingRobotics

@Hardware_SortingRobotics With some further testing, setting the input pin to spi.cs1 causes the temperature readout to go to 2000C instead. This is a type k thermocouple btw.

Phaedrux

Can you post your full config.g and the results of sending M122 and M98 P"config.g" ?

gloomyandy

@Hardware_SortingRobotics Can you also post the output from running M308 S4 (or S5 depending upon what value you are using).

Hardware_SortingRobotics

@Hardware_SortingRobotics @CHRISHAMM We just discovered a serious discrepancy in the thermocouple daughterboard documentation.

When addressing the thermocouple daughterboard, spi.cs0 does not address the first sensor on the daughterboard. The documentation states that the pins are spi.cs0-spi.cs3. We have found that the actual addresses are spi.cs1-spi.cs4 instead. Spi.cs0 is not recognized by the system as a valid pin name.

Hardware_SortingRobotics

@Hardware_SortingRobotics I'm seeing now that the 6XD documentation does actually have the correct pins listed. This information is, however, incorrect on the "connecting thermocouples" page.

jay_s_uk

@Hardware_SortingRobotics one for @droftarts

droftarts

@jay_s_uk @Hardware_SortingRobotics Yes, this catches me out, too! Pin 3 of the temp_db header is the first numbered spi.cs pin, and on all Duets it is spi.cs1 except the 6HC and 3HC, where it is spi.cs0.

Most of the documentation treats the 6XD as being similar to the 6HC, but in this respect they are different. I'll check and update the documentation for the temperature daughterboards. I've recently gone through this for the accelerometer documentation; I forgot to check the temperature daughterboards section. Apologies for the documentation inaccuracy!

Ian