Design Requirements of Analogue Transmitters for Use in Hazardous Atmospheres

Abstract

This paper considers some of the major design parameters of transmitters with direct current analogue output which are normally associated with measurement in the petrochemical industries. Specific recommendations are made for signal current, the number of wires to be used, techniques for achieving explosion protection, temperature classification, operating voltages and output impedance. Mechanical construction, termination requirements and interference rejection are discussed. The paper concludes with a reference to some practical examples of recently designed transmitters.