@rjenkinsgb Have you try the semi automatic calibration ?
https://duet3d.dozuki.com/Wiki/Calibrating_thermistor_and_PT1000_readings

@rjenkinsgb Have you try the semi automatic calibration ?
https://duet3d.dozuki.com/Wiki/Calibrating_thermistor_and_PT1000_readings

@serge

@serge I made the modification to the B4725, and the bed temperature seems to be much more real now.

I think i will try whith this value now.

@dc42 No, i don't.
Did you think i have to modify the B3950 to B4725 ?
I don't know what thermistor is for B3950.

@marshal Here is the documentation from RatRig

@dc42 Hi, no, don't get more accurate.

@dc42 Hi, the temp input for the bed is directly on the Duet 6.
; Heaters
M308 S0 P"temp0" Y"thermistor" T100000 B3950 A"Bed" ; configure sensor 0 as thermistor on pin temp0
M950 H0 C"out1" T0

@serge After reboot, same temp values.
It seems the hotend temp value is correct, but not the bed temp than i have to calibrate.

@serge
20/12/2021, 14:29:43 M308 S1 H999
Measured H correction for port "20.temp0" is -6

Hi, same issue with me
20/12/2021, 14:25:59 M122 B20
Diagnostics for board 20:
Duet TOOL1LC rev 1.1 or later firmware version 3.4.0beta7+1 (2021-12-18 13:47:42)
Bootloader ID: SAMC21 bootloader version 2.3 (2021-01-26b1)
All averaging filters OK
Never used RAM 2576, free system stack 2788 words
Tasks: Move(notifyWait,0.0%,153) HEAT(notifyWait,0.2%,115) CanAsync(notifyWait,0.0%,65) CanRecv(notifyWait,0.0%,76) CanClock(notifyWait,0.0%,65) ACCEL(notifyWait,0.0%,61) TMC(delaying,3.0%,57) MAIN(running,91.9%,351) IDLE(ready,0.0%,26) AIN(delaying,4.9%,142), total 100.0%
Last reset 00:05:17 ago, cause: software
Last software reset data not available
Driver 0: pos 0, 830.0 steps/mm,standstill, SG min 0, read errors 0, write errors 1, ifcnt 35, reads 27864, writes 12, timeouts 0, DMA errors 0, CC errors 0, steps req 0 done 0
Moves scheduled 0, completed 0, in progress 0, hiccups 0, step errors 0, maxPrep 0, maxOverdue 0, maxInc 0, mcErrs 0, gcmErrs 0
Peak sync jitter 1/5, peak Rx sync delay 214, resyncs 0/0, no step interrupt scheduled
VIN voltage: min 24.6, current 24.7, max 24.7
MCU temperature: min 30.6C, current 30.7C, max 30.8C
Last sensors broadcast 0x00000002 found 1 184 ticks ago, 0 ordering errs, loop time 0
CAN messages queued 6288, send timeouts 0, received 2853, lost 0, free buffers 37, min 37, error reg 0
dup 0, oos 0/0/0/0, bm 0, wbm 0, rxMotionDelay 0
Accelerometer: LIS3DH, status: 00
I2C bus errors 0, naks 3, other errors 0