| 摘要 |
<p>A serial data communication loop system includes single input-output controllers and/or dual message transmission with a novel adaptor unit for converting from a single to dual message frame and/or from a dual to single message frame. The message frames are multiple bit binary coded signals. The adaptor unit includes first and second converting sections, the first converting from a single input to dual output message frames and the second from a pair of identical messages to a single message output. The first section includes an amplifier connected to a polarity and level sensor and to a time delay which activates a disable timer to the amplifier and a strobe timer to operate a pair of transmitters to transmit the dual message frames. The second section includes a pair of receivers connected to a logic selector in combination with individual monitors which encode the status at the receivers to normally transmit from one receiver and automatically change to the second if the first fails. The adaptor may connect the input and output ports of a controller to a pair of parallel transmission trunks, automatically switch between main and back-up loop controllers connected in either a single or multiple trunk system, and provide an individual or group remote unit with message continuity if an individual or group loop is broken.</p> |
