If you need a third extruder on megatronics with thermocouple reading, or want improved temperature readings on RAMPS, you can use this board. It connects to any analog pin on the electronics and is supported by Marlin firmware.
- Compatible with RAMPS 1.4, Megatronics 1.0 and 2.0
- Easy to connect
Hooking up to Megatronics
Locate the Serial pins on the board (just below the stepper driver slots). Match the red wire with +, the black with - and the yellow with signal.
Hooking up to RAMPS
Locate the A-Out pins on the board in the aux-1 section. Match the red wire with +, the black with - and the yellow with signal.
Settings in Marlin
In configuration.h, select -1 as temperature sensor. For example:
#define TEMP_SENSOR_0 -1
In pins.h adjust the temp pin for you electronics to the analog pin (on both RAMPS and Megatronics pin 3, if connected through the examples above). For example:
#define TEMP_0_PIN 3
Be sure that you edit the TEMP_0_PIN from the motherboard you use. if you use the ramps motherboard, you have to edit TEMP_0_PIN on line 372 in the pins.h if you have another motherboard you have to know the number in the marlin software, and seek for if MOTHERBOARD == "your number of motherboard" (you will find this for the first time on line 16 and the next statement is on line 62).
For the newest Marlin 1.1.9, change configuration.h line 313 to -1. Navigate to RAMPS.h and modify line 194 #define TEMP_0_PIN to 3. Note that the current Arduino IDE (1.8.9) contains a bug that will not allow the sketch to compile, but an older version such as 1.8.5 will work.
After uploading the firmware, you should have thermocouple readings now.
DesignSpark sources: File:Extthermoucouplesrc.zip