I made a post a while ago about having large excursions when reading from my MAX6675. Despite using adum5401 digital isolator to float the MAX6675 as suggested in the original post, I still see a lot of noise on the MAX6675 thermocouple input using a scope.
I did notice on the MAX6675 board there's only one bypass cap on the the VCC rail. There is absolutely no filtering on the thermocouple input.
Questions: 1) Can I apply some filtering on there?
2) I read on a different forum that the thermocouple amp should ideally be connected to analogue GND and that the AVR microcontrollers don't have any. By using a ADUM5401 to float the MAX6675, have I effectively created an analogue GND? If so, it's still no go.
Any help would be very much appreciated!