1. Basic Program Design Examples 1.9 SET/RST - Latched and Unlatched Circuit START X0 X1 STOP X2 Y0 Control Purpose: z Press START, the pump begins to pump out the water; press STOP or when the water is empty, the pump stops working. Devices: Control Program: Program Description: z X2 will be ON If there is water in the container. When START is pressed, X0 = ON, and SET z There are two situations for stopping the motor. First, when STOP is pressed, X1 = ON. PLS instruction will be executed. Y0 will be set, and the pump motor begins pumping the water. instruction will be executed and M0 will be ON for one scan cycle. RST instruction will thus be executed, and Y0 will be reset to stop pumping.
Second, when the water in the container is empty, X2 will be OFF and PLS instruction will be executed to trigger M0 for resetting Y0. In this case, the pump motor will stop pumping as well. DVP-PLC Application Examples 1-9 Device Function X0 START button. X0 will be ON when pressed X1 STOP button. X1 will be ON when pressed X2 Level detector. X2 will be ON if there is water in the container M0 Trigger pulse for one scan cycle Y0 Pump motor X0 X2 X1 SET Y0 X1 PLS M0 X2 M0 RST Y0 RST Y0 SET Y0 PLS M0