It has been recognised, that there is a need to employ improved development methods when designing Manufacturing Automation Systems. This need is addressed in part by the implementation of the IEC 61131-3 Standard. Best development practices require that control systems for Programmable Logic Controllers (PLCs) and Process Automation to be developed in a manner that engenders modularity and reuse. Development methodologies such as the Object Modelling Technique (OMT) and the Booch Method have previously been investigated. This paper sets out the basis for the suitability of UML and modelling in programming in the Manufacturing Automation sector of electronics.