Thank you for the reply. Laptop running on battery didn't fix that. The thermocouples are grounded K-type thermocouples to measure the temperatures in a burner. Some of them touch the metal surface. Some are not. I will try to connect the common ground of the circuit to the burner's metal surface to...

We currently use TC-08 for temperature and voltage measuring. Channel 1-6 are for thermocouples inputs while channel 7-8 are for voltage measuring (0-5V). We got two TC-08 Single-Channel Terminal Boards to convert the voltage. (switch set to OFF). The problem is that when we try to measure the volta...