| 摘要 |
PURPOSE:To allow a master station to supervise all slave stations by switching a display line of all slave stations to a control line when the master station of the polling type remote supervisory system detects a fault of the display line to transmit the display data through the control line. CONSTITUTION:The master station 1 and the plural slave stations 2 are connected by the control line 3 and the display line 4 so as to attain the polling type remote supervision. When a logical control section 1b of the master station 1 detects a fault of the display line 4, a line switching section 5 is controlled via a signal line 6, relay contacts 5x, 5y are switched and the display line 4 is released and the control line 3 is switched to the display input side. Moreover, a logical control section 1b transmits a line switch signal from the control line 3 to all the slave stations 2 ahead the changeover by the master station, the logical control section 2b drives the line switching section 7 via a signal line 8 to change over contacts 7x, 7y thereby transmitting the display data to the control line 3. Thus, the master station continues the supervision of all the slave stations.
|
