I m using S7(Siemens PLC) . I wanna ask how can we do looping using Ladder lagic? Say i want to make LED flesher which flesh LED infinite times or 10 times !! is there any possibility to make this logic on ladder logic or I have to use STL ??
A similiar logic shouldn't be realized with loops in ST or any other PLC programming language. A loop effectively holds execution of PLC cycle.
Use a counter or a count variable and a timer respectively one of the available systimer ticks instead. This should be basically possible with any PLC programming technique.
The basic concpt of a PLC is executing the main code (OB1) repeatedly. Acceptable cycle time depends on the application, with slow processes several 10 ms may be O.K. Blinking the LED in a loop would extend cycle time to several seconds, acceptable only for a PLC that has no other outputs than the blinking LED.
I'm sure that you can find some blinker examples in PLC tutorials that are compatible with regular operation.