Hot End Thermistor incorrect after duet replacement

Hi All,

After moving house and getting sorted, I plugged in my Ormerod 1 and found that the steppers no longer moved. unsure why or how.. I couldn't see any burnt out components etc and eventually ended up swapping out the duet board for another 0.6.

Once all connected up I flashed the same version of firmware I was using on the SD card (DC's v1.17) until I was happy everything was working. Once flashed I tested everything was ok and all but the hot end thermistor seemed to be working as expected.. I tried to run M305 P1 and change the values as suggested (For firmware versions 1.17 and later, set the B parameter to 4725 and the C parameter to 7.06e-8) on the e3d v6 assembly instructions but this still didn't resolve the issue. The hot end was still reading 1 degree.

I then upgraded to the latest stable release (1.21) to test, I copied the ormerod sys folder over and renamed to just sys and copied over my config.g file from my old sd image across to the SD, the hot end now reads 2000 instead of 1 degree, but now when I run M305 I get a message stating that heater 1 is not configured. I tried running M305 P0, which returns "Heater 0 uses Thermistor sensor channel 0, T:10000.0 B:4719.0 C:0.00e+00 R:1000.0 L:0 H:0" I assume this is the heatbed?

Has anyone had any similar issues or any suggestions for something to try to get this working again at all please? Id love to start printing again, its been too long!

Many thanks

Dan

The R1000 parameter in M305 should be changed to R4700 for all but the earliest Duets.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks, So on the newer firmware is P0 now the hotend thermistor or is that the heatbed?

I just found this line was commented out on the config.g file, I enabled this and changed R1000 to R4700 but still no change

"M305 P1 R4700 H0 L0 ; Put your own H and/or L values here to set the first nozzle thermistor ADC correction"

P0 is still the bed thermistor and P1 is still the hot end.

You didn't describe in what way the thermistors are not working. The symptom of using R1000 in M305 commands when you should use R4700 is that the thermistor reads about 60C when at room temperature.

Recent versions of RRF require a M305 command in config.g for every thermistor.

Edited 1 time(s). Last edit at 04/02/2018 04:42PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Sorry I should have made that clearer, The hot end thermistor was reading between 1 and 6 degrees C with the R value being 1000, If i change it to 4700 then it reads 2000 degrees. The bed is reading 20 degrees which is about right for ambient room temp.

This is an extract from my config.g file

";*** If you have a Duet board with 4.7K thermistor series resistors, change R1000 to R4700 to the following M305 commands
M305 P0 R1000 B4719 7.08e-8 H0 L0 ; Put your own H and/or L values here to set the bed thermistor ADC correction
M305 P1 R4700 H0 L0 ; Put your own H and/or L values here to set the first nozzle thermistor ADC correction
;M305 P2 R4700 H0 L0 ; Put your own H and/or L values here to set the second nozzle thermistor ADC correction
;*** Adjust the XY coordinates in the following M557 commands to suit your build and the position of the IR sensor"

I am only running a single nozzle setup, using a genuine E3d V6 with the cartridge thermistor which came with the hot end.

the thermistor and hot end has been previously working fine.

OK so you are using a Duet 0.6 with 1K resistors. It's not unusual to get a temperature offset of that magnitude with those boards, that's why the resistors were changed to 4.7K in later versions. You can adjust the H parameter in the corresponding M305 command to correct it. I suggest you change H by about +/- 10 at a time until you get close.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].