Air conditioning control circuitry with redundancy - has internal controllers in all devices activating redundant ready devices when redundancy line voltage changes

摘要

All devices (1-6) forming a system contain internal controllers (DDC1-DDC6). Each internal controller has a redundancy contact (101-106) connected to those of the other controllers via a redundancy line. If one controller fails it causes a voltage change on the redundancy line. Failure of a device results in further devices being switched on to maintain the operation of the system. The controller of a device in the ready state responds to the redundancy line voltage change by switching the device on. USE/ADVANTAGE - Controlling air conditioning systems with redundant devices. Intrinsically safer than conventional systems.