OP described remote temperature sensor for a PLC. What you might want to do with data might changed, but how we gather it only got optimized down to specialized controller chips. Amplification, compensation, linearization - all taken care of by dedicated interface chips, something like AD849x, MAX6675/MAX31855 or ADS1118. There is nothing left to do at the remote end that cant be done further down the line. Measurement is pretty much Push Button, Receive Bacon to the point you can build your own soldering station with arduino, one of those chips, mosfet and a display module in 100 lines of code.