Hello everyone,
I have a strange problem with my Arduino project using the MAX6675 module to read type K thermocouples. The Arduino is connected to a notebook. When the notebook runs on battery, without using the 230V power adapter, I can read data from the MAX6675 module without any issues. However, when I plug in the power adapter to the notebook, the readings immediately become bad (showing very low values).
The thermocouple is grounded in steel and is in contact with a metal container that's also grounded (it has its own control electronics). The notebook is plugged into a different electrical outlet with its own ground.
I'm worried that there might be a ground loop causing this problem. How can I fix it?
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I apologize. I posted my issue on the international forum because no one had responded to my question on the Italian forum.
I tried your suggestion, but it had no effect.
The thermocouple wiring is about 70 cm long, and I don't think that's the source of the problem because when I connect another thermocouple (with the sheath not grounded), I don't have any signal issues.
