Reading negative temperature and N/A temp

johny

Hello,
After wiring all (duet 2 wifi v1.04) i get the following temp reading:

what whould it be? i already changed the B value from the gcode, re-wire, it doesn't change.
Thank you

Danal

-273.1 is the "magic number" that indicates a totally open circuit on an input configured for a thermistor. So you have a broken wire, are plugged into the wrong input, or similar.

johny

@Danal Thank you for your help; even without anything plugged i get the "magic number", what should this indicate?
What about the n/a one?
Thank you

A Former User

@johny said in Reading negative temperature and N/A temp:

even without anything plugged i get the "magic number", what should this indicate?

that your thermistor isn't properly connected when you think its connected.

Danal

@johny said in Reading negative temperature and N/A temp:

@Danal Thank you for your help; even without anything plugged i get the "magic number", what should this indicate?
What about the n/a one?
Thank you

even without anything plugged i get the "magic number"

That is exactly what it means: Open circuit; nothing plugged in.

Not sure about the N/A

jay_s_uk

@johny
What type of thermistors are you connecting and where are you connecting them?

Please also post your config.g file

johny

Hello,
For the heat bed it is the standard thermistors from Chinese heat beds, for the hot end its the one: ATC Semitec 104GT-2/104NT-4-R025H42G (http://www.atcsemitec.co.uk/gt-2-glass-thermistors.html )

Gcode:

; Heaters
M307 H0 B0 S1.00
M305 P0 R4700 T100000 B4267 C0.0000000706
M143 H0 S130
M305 P1 R4700 T100000 B4267 C0.0000000706
M305 P2 R4700 T100000 B4725 C0.0000000706
M143 H1 S275

; Fans
M106 P0 S0 I0 F500 H-1
M106 P1 S1 I0 F500 H1 T45
M106 P2 S1 I0 F500 H-1

; Tools
M563 P0 D0 H1 F0 ; define tool 0
G10 P0 X0 Y0 Z0 ; set tool 0 axis offsets
G10 P0 R0 S0 ; set initial tool 0 active and standby temperatures to 0C

; Custom settings are not defined

; Miscellaneous
M911 S10 R11 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000"
T0 ; select first tool

jay_s_uk

@johny

Apart from having 3 thermistors setup with only 2 heaters, nothing jumps out at me as being odd.
Could you take a photo of where you are connecting the thermistors?

johny

Regarding to where i am connecting them its according to the wiring, also it is printed in the board E0 temp and bed heater :

bead heater

hot end heater

Edit: i tried to connect to the E1 thermistor as well to check if it works that's why it have 3 thermistors setup

jay_s_uk

@johny

Is the second image correct? that you are attaching the thermistor to the green terminals?

johny

no sorry! In that i plug the heater, the thermistor is bellow
alt text

jay_s_uk

I would set the values to the following

M305 P0 T10000 B3950 R4700               ; set thermistor + ADC parameters for heater 0
M143 H0 S120                             ; set temperature limit for heater 0 to 120C
M305 P1 T100000 B4725 C7.060000e-8 R4700 ; set thermistor + ADC parameters for heater 1
M143 H1 S280                             ; set temperature limit for heater 1 to 280C

The P0 is a generic 3950 which is what tends to be used by chinese suppliers.
The P1 is correct for a 104GT

I would remove the P2 as this is probably confusing things.

If you're still getting no values, I would revisit your crimping

johny

I did those changes and i even solder a pair of wires directly to the bed thermistor to bypass any broken cable, the magic number is still there.
Probably is something burn in the board, what could it be?
Thank you

jay_s_uk

You could try remapping the bed thermistor to P2 and connecting to the e1 temp header and see if you get a reading

johny

I did it, no luck, still same error :S
I unplugged a thermistor from another printer to check it if was the thermistor and the same result.

A Former User

(Don't think there is one)

johny

@bearer said in Reading negative temperature and N/A temp:

(Don't think there is one)

Well i measure between the vssa and gnd and i got 3 ohms.
I just checked that my heat bed had a short between the +12v and gnd but i got no readings even before plugging it.

blt3dp

What version of the firmware does M115 report? Might be useful in troubleshooting.

johny

@blt3dp said in Reading negative temperature and N/A temp:

M115

M115
FIRMWARE_NAME: RepRapFirmware for Duet 2 WiFi/Ethernet FIRMWARE_VERSION: 3.0 ELECTRONICS: Duet WiFi 1.02 or later FIRMWARE_DATE: 2020-01-03b3

blt3dp

@johny said in Reading negative temperature and N/A temp:

FIRMWARE_VERSION: 3.0

That's why you're not getting a reading, you need have to define the pin that it's using.