| 摘要 |
<p>A plurality of selectively switchable loads can be addressed from a central station over a ring bus system which has at least a clock bus and a control bus. The central station includes a timing counter which sends signals, for example in groups of pulses, on selected buses forming selection cycles to address specific loads and control signals to separate sequential selection cycles. These signals can be decoded at the receivers. To ensure operator supervision of proper operation of the system, a pulse interrogation stage is connected to at least the clock bus of the bus system and responsive to the occurrence of pulses thereon, and providing an alarm output or warning signal, possibly operating a warning device if the pulses do not occur as they should.</p> |
