I want to change the thermistor to thermocouple with SPI connector.
I just wondering how I can connect 2 of them if I want to use 2 extruders?
There is only one SPI connector.
You just need to choose another pin on the smoothieboard to connect to the CS (chip select) for the second thermocouple, and update the configuration correspondingly.
GND, V3V, MOSI (master out slave in) and SCK (spi clock) should be connected in parallel for both thermocouples.