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.
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
PLC ONE 