In Example 18.10, there are two switches to start the pump. In addition, consider that the pump can be automatically started by a newly installed high-level switch as long as the stop switches are not pressed. Modify the ladder diagram shown in Figure E18.10(b) accordingly.

Example 18.10

Figure E18.10

Transcribed Image Text:

Figure E18.10(a) shows the schematic of a storage vessel, V-101. Pump P-101 has two start and stop switches (one in the plant and the other in the control room). Assume that the pump start switch is a momentary signal, that is, is true as long as the start button is pushed. The pump can be started or stopped by either of the start/stop switches. Pump P-101 should stop if the level of the vessel becomes low as detected by the level switch, LSL- 101. Develop a ladder diagram for the pump.