| 摘要 |
PURPOSE:To make it possible to transmit signals for supervisory control over decentralized loads with simple two-core circuit constitution by cascading subordinate stations consisting of a current transformer and photo coupling element via two-core signal lines. CONSTITUTION:When master station M makes LED of photocoupler 6 of signal line 3 come on, its transistor TR also comes on. As a result, currents flow from DC power source 5 by way of current transformers 14-14n of subordinate stations S1- Sn and diode 17. Respective subordinate stations receive the currents via current transformers 14-14n. Then, master station M makes LED of photo coupler 6 come on-off and after the code of individual 1 is transmitted, photo coupler 6 is made to go off; and LED of photo coupler 10 is made to come on to make reception ready. For example, when subordinate station S1 makes LED of photo coupler 15 to come on to send out a return signal, master station M detects that by current transformer 12 and judges that it is sent back from subordinate station S1. Further, individuals 2, 3... are similarly treated. |
