Learning PLC programming, we often encounter the sequential control, but how to make plc ladder diagram，there is  example Shuttle program.The initial state of the car parked in the middle (limit switch X0 is pressed, the normally open contact closure),Press the Start button (X3 closed), the car began to follow the direction shown to reciprocate when … Continue reading PLC ladder programming sequence control

plc programming often using timers and counters for  Sequence delay control.After X0 is turned ON,begin delay, after 10s Y0 turn on, after delay 20s Y1  turn on, after  30s Y2 turn ON. http://www.plchelpcenter.com/2016/07/10/sequence-delay-control-plc-ladder-diagram-program.html

When plc programming often need several hours, or even longer delay, the best way is  series timer, or  PLC internal counter.Using the timer series Can be a long delay, in essence, it is to allow multiple timers turn ON, delay time is Accumulating multiple timer settings. Serial time delay Set time of the timer T1 … Continue reading how to program long delay PLC ladder diagram

When the X0 is turned on, the timer T1 starts to delay, after 2S Timer T1 normally open contact closure (set point signal), hold instruction make the Y0 power and hold; When the X0 is off, the timer switch on T2 (normally open contacts at Y0) start delay, 4S timer T2 normally open contacts (reset … Continue reading how to program Power Delay on and Power loss delay off PLC ladder diagram