Thermocouple Measurements without Custom Electronics

Abstract

Thermocouple measurements require “cold junction” compensation in order to obtain a correct reading. This compensation has traditionally been done with custom circuitry. In flight test applications where volume and power are at a premium (e.g. weapons flight test) it is desirable to have a more flexible solution that uses standard analog data acquisition channels already available as part of the encoder circuitry and performs compensation with remote software. This can be done via digital compensation, but certain measures must be taken to maintain accuracy and minimize noise. This paper describes some of these techniques and their performance tradeoffs.