Influence of Programmable Logic Controller Program Structure to Digital Inputs Reaction Time.

Design of digital control systems is often based on use of Programmable Logic Controllers (PLC). Such devices offer a broad variety of functions that can be organized in blocks independently or in hierarchical structures. Such an organization can lead to cumulative delays in reaction time of digital outputs of the control system. In the paper there are described results of research aimed to determine dependencies of various aspects of designing programs for Programmable Logic Control devices influencing the effective time of reaction of digital outputs. Research method is presented, assumptions are made, and experiments are described and discussed. Observations of system behavior are presented for selected control tasks and different control situations. Research results are presented and discussed, conclusion is drawn, and areas of future work are identified. [ABSTRACT FROM AUTHOR]