Remote control circuit breaker system with on-off-tripped-problem status storage and indication

摘要

A remote control circuit breaker and contactor system having at least one I/O circuit functioning as an interface between a central processing unit and a plurality of up to 32 devices such as remote circuit breakers for each I/O circuit, each remote circuit breaker having an individual electronic circuit which receives commands from the I/O circuit to turn the breaker or contactor on or off or hold and also senses the state of the breaker contacts and the control line and upon request sends back status codes which are stored in the memory in the I/O circuit to be read when desired by the central processing unit. Four- state status information is provided including open, closed, tripped and problem (low voltage, open or shorted control line). Contact state is determined by directly measuring the contact resistance in single break contacts (or solid state device contactors) or the contact voltage in double-break contacts. The I/O circuit provides noise rejection using measured noise as a threshold to minimize the effect of electrical noise on the status communication signals coming from the remote breaker electronic circuit. In the event electrical noise on the control line or the like causes rapid turn-on and turn-off of the remote breaker, a rapid cycle inhibit circuit for a timed interval stops such cycling of the remote breaker after a predetermined number thereof to prevent damage to the remote device due to overheating. The remote breaker electronic circuit affords manual control of the breakers or contactors and trip indication of the breakers in addition to computer control through the I/O circuit. The system uses tri-state communication circuitry which includes a hold command and prevents unwanted state changes during losses of power or when a control line shorts to ground or opens.