| 摘要 |
PURPOSE:To enable an operator to understand clearly the state of a system, by turning on successively plural pilot lamps arrayed on a mimic line in accordance with the path and the flowing direction of the fluid of a pipeline. CONSTITUTION:For instance, a signal is applied to a terminal 92 when the starting conditions are satisfied. Thus a base current flows to a TR77 via an AND circuit 79, and therefore the TR77 conducts to turn on light emitting diodes 751-75n all at once. When a signal is impressed to a terminal 91 after the operating conditions are satisfied, the base current is impressed to the circuit 79 via an NOT circuit 99. As a result, the TR77 is not conductive to turn off all light emitting diodes. Furthermore the diodes 751-75n glow since the signal impressed to the terminal 91 is impressed also to a decoder 83. Thus it is possible to control the lighting of the pilot lamps on a mimic line in accordance with the state of operation of the process control. |
