Solved Debug MAX31865 over CAN
My 3D printer is equiped with a Duet 3 MB 6HC and one Duet 3 EB 3HC.
On the extruder, I use 3 PT100 sensors and a fourth one for the heated build plate. All PT100 sensors are connected to the Duet 3 boards through a MAX31865.
On this printer, I can read all the temperatures of the PT100 sensors.
When I heat the extruder and extrude, I can still read all the temperatures normally.
But, once I start a print, I have two sensors on the extruder showing me 2000°C and the third one 0°C. Shortly after, I lose the connection on the Mother Board and the print is stopped.
The last time I got that error message : Error: M308: Response timeout: CAN addr 1, req type 6011, RID=901
The previous time I had this one : Failed to upload dwc2settings.json
Operation failed (Reason: Your Duet rejected the HTTP request: Unknown message type or not authenticated)
Once the sensors are showing me these anormal values I wasn't able to reset them, even with a M562, unless reseting the whole printer.
Here is what I get when trying a M308 S4 : Sensor 4 type PT100 (MAX31865) using pin 1.spi.cs2, last error: success, 2/4 wires, reject 50Hz, reference resistor 400 ohms
The issue only concerns the sensors that are connected to the Duet 3 EB 3HC. The build plate sensor doesn't have any problem.
I am kind of stuck here so any help would be appreciated.
[Edit] : It seems that there is a CAN connection failure right when the temperature sensors start showing the incorrect values.
Once the CAN connection is working again the temperatures are either incorrect either non existent ( no sensor is found.
What firmware versions are you running on the main and expansion boards?
Thank you for taking time to answer.
The firmware versions of the mother board and the expansion board are respectively :
FIRMWARE_NAME: RepRapFirmware for Duet 3 MB6HC FIRMWARE_VERSION: 3.1.0 ELECTRONICS: Duet 3 MB6HC v0.6 or 1.0 FIRMWARE_DATE: 2020-05-15b1
Board EXP3HC firmware 3.0RC1 2019-12-16b1
Veti last edited by
from the changelog
M111 supports CAN module debug
Time for a firmware update to at least 3.1.1
yb last edited by yb
I tried to update the firmware to 3.1.1 for the expansion board and still had the problem but without having the sensors temperatures showing 2000°C.
With the firmware 3.2-beta3.2 on both the expansion and the mother boards it seems that the issue is gone.
Thanks a lot for the answers!
I'm glad it seems to be solved. Please upgrade to 3.2beta 4, which fixes issues in 3.2beta 3.2.