| 摘要 |
PURPOSE:To perform a remote monitoring with high efficiency and a simple constitution, by using a DC power supply of a master station in common with a control power supply of each slave station and at the same time by enabling the monitor for the working state of each slave station although the number of transmission lines is decreased. CONSTITUTION:Switches S1 and S'1 are made into a pair and turned on and off at one time. Now both switches are turned on to monitor a slave station C1. As a result, the station C1 is connected between power supply terminals E1 and E2 via transmission lines L1 and L2. Thus a receiving relay R becomes active or inactive in response to ON or OFF at a point A1 to be monitored. When slave station C2 is monitored, both switches S2 and S'2 are turned on. In this case, the C2 is connected between the terminals E1 and E2 via the lines L1 and L2. Then the relay R becomes active or inactive in response to ON or OFF at a point A2 to be monitored. In such a way, each slave station is selected and a contact to be monitored can be monitored by having a pair of switches. |
