I've been reading up on thermocouples (TC) interfaces and the concept looks simple in theory, but possibly not so easy in practice. It looks like it is important to use an amp with a very low Vos because of the small signal.
I am thinking that the cold junction compensation can be done in software by using a thermometer on the board near the connector. Otherwise it doesn't look too hard. I'll be using low pass filters to limit high freq noise and most likely use a synchronous sampling method to integrate 50/60 Hz noise away. If the TC is connected to the board with an extension cable, where is the cold junction that needs to be compensated, on the board still or at the TC to cable connection or both? I expect it will be at the extension cable junction since the extension cable to connector will be identical metal types. I guess we'll avoid extension cables...
I am not looking to use any of the TC interface chips available because they tend to be pricey and not so small.
Are there any aspects I am missing that will make this not so easy?
Rick