A general purpose sequencer/controller: an alternative to ladder logic

GESEC (generalized sequential and continuous controller) was written to transform a microprocessor-based remote-control unit into a PLC-like (programmable-controller-like) device which could be programmed by the user in a high-level, process-oriented language. The target machine for the initial project was a Taurus One/10 controller based on a Z80 microprocessor. GESEC and the GLC compiler together produced a very viable option for control involving both sequential logic and continuous analog control. It is predicted that, with improvements to the compiler, the ease with which well-documented code can be produced will be comparable to that for most of the present industrial controllers. Program structure and operation, PID (proportional, integral, derivative) control, and programming aspects are discussed, and the application of this system to a touch-up oven is discussed