Microprocessor-based control retrofits: Old and new technology for contractors
Beginning in the early 1980s, microprocessor-based controls have been used to replace electrical-mechanical control systems on compressor and chiller packages. Traditional electromechanical components (pressure switches, rotary drum timers, temperature switches, freezestats, wiring, relays, etc.) have given way to microprocessors, EEPROMs, transducers, RTDs, analog circuits, and digital I/O modules.
The trend toward microprocessor-based systems is prevalent in both the hvac and industrial refrigeration industries.