Two wire system for selective grouped load control - has microprocessor for digitised control of senser and receiver modules operating on multi-bit signals for enhanced reliability

摘要

The control circuit uses a two wire system for conveying a DC operating supply to the loads as well as their digitised command signals. A control module (12) contains the DC source to the two wire bus (14), a variable frequency generator, an analogue/digital convertor with load sensing circuit, a signal reference/comparator unit, a pulse regulator and semiconductor switch under overall supervision of a microprocessor (20). Individual receivers (16) control each load (18) via a microprocessor Schmitt trigger and field effect transistor. USE/ADVANTAGE - Enables simultaneous transmission of operating power and control signals, e.g. for valves over same two wire bus. Has inbuilt error detection for verifing signals and indicating control or load malfunction.