8-channel Thermocouple Input Module. The I-87018W is an 8-channel analog input module that provides current input and voltage input, as well as thermocouple input. The I-87018RW is an upgraded version of I-87018W with an extremely highquality protection mechanism where the overvoltage protection can be as high as 240 Vrms. The input type can be set to either current or voltage, as well as thermocouple. The only difference between the two modules ..