Chapter 2 0BProgramming Click ???, and type “Pump_Out”. Users can double-click the coil marked “Pump_Out”, and the drop-down list appears. Select “Set”. Please click , to add a new network. Users can write the following program in the same way. To meet the condition that there is no water in the underground pool, or the condition that the pump trips, users need to click appears, users can click the left mouse button. Then, users need to click ???, and type “Tank_B_LSW”. Finally, users can double-click the coil marked “Tank_B_LSW”. When the drop-down list appears, select “Set”. , and move the mouse to the position under a contact. When 2-25