Logic solver application software and operator interface

By RJ Perry, Control Systems Consultant


Published in:

Electricity+Control, October 2013 (pages 24 – 28)

Enquiries: Email rjperry@nashuaisp.co.za


The full article on Logic solver application software and operator interface can be downloaded in PDF format.


Prior to 1998, there were few standards dedicated to functional safety management as applied to programmable instrumentation systems, and initially there was a reluctance to use ‘software’ in safety applications due to issues with reliability and systematic ‘bugs’.

The typical electromechanical trip relay system standard design - although reliable with well defined failure modes - suffered from many drawbacks such as system modification and lack of intelligent communications.

This article shows that correctly implemented and structured functional logic, and operator interface displays, can improve overall functional safety management and reduce systematic failures leading to fewer process plant accidents.


Take note 

  • Software is ubiquitous in modern control systems.
  • Plant safety can be affected by software on the plant.
  • Safety requirement specifications can be implemented – but guidelines must be followed.