I have a circuit board i designed that has input for two clamp type thermoucouples. Each circuit is connected to an instrumentation amp (INA126). They both work fine individually, but when two are used and both clamps are connected to the same pipe thay read incorrectly. The problem stems from the fact that the clamp type thermocouples have a metal conductor for thermal conductivity directly connected the thermocouple junction. Both low sides of the cold junction(connection at the board) are connected to each other. Has anyone run into this and have a solution?

 

insulate the clamps.