General PLC timer delay time is short, such as the FX series PLC in the 0.1s timer timing range for 0.1~3276.7s, if you need to delay even longer the timer, Cascade using multiple timers can be used to realize the long time delay. Cascade when used for timer, the total time for the timer clock time and.
As shown in Figure 5-10 time 1h ladder diagram and sequence diagram, auxiliary relays M1 for scheduled start–stop control, Cascade use two 0.1s timer T14 and T15. T14 start after timing, delay 1800s T14 normally open contact closure, T15 start timing again, and by the 1800s the delay, T15 normally open contact closure, Y4 coil connected. X14 connected to Y4, the delay time is 1800s+1800s=3600s=1h.