Hi i am building my own dual extrusion 3D printer. I have RAMPS with defined Motherboard_14_EEB and connected two thermal sensor 1 at T0 and another one at T1. The printer doesnt contain any heatbed.
Scenario:
Temp sensor both classified as 1 in Marlin.
T0 shows 25degC room temperature and is able to heat up.
T1 shows 0degC.

Swapped T0 to T1,
new T0 now shows 0degC and T1 also 0degC.

Please help.

Edited 1 time(s). Last edit at 08/09/2016 10:54PM by RevoCayne.

I would guess two issues

Firstly the one of your thermistors + cables looks like its open circuit, remove the cable from your board and check the resistance threw the cable and the thermistor, should be around 100K at 25C

Secondly it looks like you don't have a second thermistor defined in your firmware, so it just not looking at it.

Edited 1 time(s). Last edit at 08/08/2016 06:31AM by Dust.

My configuration file is as follow.

#define EXTRUDERS 2

#define HOTEND_OFFSET_X {0.0, 20.00} // (in mm) for each extruder, offset of the hotend on the X axis
#define HOTEND_OFFSET_Y {0.0, 5.00} // (in mm) for each extruder, offset of the hotend on the Y axis

#define TEMP_SENSOR_0 1
#define TEMP_SENSOR_1 1
#define TEMP_SENSOR_2 0
#define TEMP_SENSOR_3 0
#define TEMP_SENSOR_BED 0

what am i missing?

i will check the resistance tomorrow

Hi, i have done another troubleshooting which proved that my 2nd thermal sensor is not working because one wire inside the heatshrink tube had loose.
But now i have plugged with another working thermal sensor, the T1 is still not picking up signals. i swapped again T1 and T0 to see if the ramps could get the new thermal sensor and it shows 25 degC.
I also changed the RAMPS to make sure it was not the problem of RAMPS. So now left is the configuration of firmware. Can anyone help me by checking what im missing in my configuration file?
Your help is much appreciated. Thanks a lot.

Do you have "HEATER_1_PIN" set to the correct pin in pins.h file

My pins.h config with no second extruder
#define HEATER_0_PIN 21 // Extruder
#define HEATER_1_PIN -1 // no second extruder - change to correct pin for second extruder
#define HEATER_2_PIN -1
#define HEATER_BED_PIN 20 // Bed

Hi,

I have pins_RAMPS.h shown below at the TEMP pins.

#define PS_ON_PIN 12
#define TEMP_0_PIN 13 // ANALOG NUMBERING
#define TEMP_1_PIN 15 // ANALOG NUMBERING
#define TEMP_BED_PIN 14 // ANALOG NUMBERING

#if ENABLED(Z_PROBE_SLED)
#define SLED_PIN -1
#endif

// Augmentation for auto-assigning RAMPS plugs
#if DISABLED(IS_RAMPS_EE && DISABLED(IS_RAMPS_EEF) && DISABLED(IS_RAMPS_EF && DISABLED(IS_RAMPS_EFF) && DISABLED(IS_RAMPS_SF) && !PIN_EXISTS(MOSFET_D)
#if HOTENDS > 1
#if TEMP_SENSOR_BED
#define IS_RAMPS_EEB
#else
#define IS_RAMPS_EEF
#endif
#elif TEMP_SENSOR_BED
#define IS_RAMPS_EFB
#else
#define IS_RAMPS_EFF
#endif
#endif

does that means i have to shift my T1 to the T2 pins on the RAMPS?

According to [reprap.org]

#define TEMP_0_PIN 13 // ANALOG NUMBERING
#define TEMP_1_PIN 14 // ANALOG NUMBERING

However this depends on order the plugs are connected.
Does the heatbed show the correct value.
Does heating the heatbed raise the reported tenperature. If it does the pins are correct.
If heating extruder 2 raises reported bed temperature then pins are wrong.
You can heat bed or extruder with a hair dryer to test if it changes.
You could also swap pins for bed and ext2 on the board to test.

I will try to swap the pins or change the codes when i get my hands on it.
However, the T1 im currently connecting to is showing 0 degC instead of room temperature.
That means its not sensing any temperature at all doesnt matter its sensor for heatbed or for extruder.
So what could be the problem then if the pin is for heatbed but still showing 0 degC.

I have double checked my code and realized that my heatbed thermal sensor was not defined. Thats why even the pins are swapped it is not picking up any signals. Now i have swapped the pins and it worked. Thanks George and Dust for helping.! Much appreciated