FP-TC 120 : Measurement of Thermocouple at different potential

[Manu56]

Is it possible to make measurement with a FP TC 120 of thermocouple which are not to a same potential? I need to measure temperature of different electrical component, with Thermocouple, welded to components. But potential betwwen components can be around 20 V...

[Aaron_G]

The [c]FP-TC-120 module is not suited to measuring thermocouples that are at different potentials. The [c]FP-TC-120 can only handle a volt or two of potential difference between channels.

Some possible solutions are to use an external switch so that only thermocouples at the same potential are connected to the module at the same time (although this does introduce extra error due to the thermal EMF of the relay) or you can use the dual channel thermocouple modules. The dual channel modules are isolated module to module, so you have a finer granularity on the commons (e.g. one common for each two channels as opposed to one common for each eight channels).

Regards,
Aaron