The Duet WiFi and Duet Ethernet support up to two daughterboards stacked (with a further two stacked on the Duex2 or 5):
Version 1.1 thermocouple boards: MAX31856-based daughter boards each supporting two thermocouples of type B, E,J K, N, R, S or T.
Older versions: MAX31855-based daughter boards, each supporting two K-type thermocouples
A total of two temperature sensor daughter boards (PT100 or Thermocouple) are supported on the DuetWifi, with a further 2 on the Duex2 or Duex5 bringing the total number of digital temperature inputs to 8.
For setting up the Duet us use PT100 sensors see: Connecting thermocouples