Accuracy in process computer instrumentation systems

IN THE LAST few years, the use of computer control systems has expanded greatly. They have grown from simple data logging applications to enormous systems with hundreds of inputs and outputs. The result has been that the system designer must contend with myriads of complex interrelationships when he is preparing a system design and specifying it properly to the computer manufacturer. It is axiomatic that as system complexity increases, the requirement for accuracy in certain portions of the system demands increasing attention. Unfortunately, the accuracy of a complicated system is neither easily defined nor understood. As a result, accuracy requirements are often ambiguously or incompletely stated. This has led to variations in the interpretation of accuracy requirements and a resulting confusion on the part of both the user and the manufacturer.