Definition

The For instruction indicates the starting point of a For - Next loop, and based on its user setting, determines how many times the For - Next loop will be executed in one program scan. Between the For instruction rung and the Next instruction rung, place the rungs of logic that should be repeated multiple times.

Caution: Placing one For-Next loop inside another For-Next loop is NOT permitted.

Setup

1 Number of loops: The Number of loops can be a constant typed directly or it can be any eligible Data Memory Address.

Note: If the Number of Loops setup is large, it will increase the program scan time.  When the program scan time exceeds the Watchdog Timer setup (Default = 200ms), the CLICK PLC drops from the Run mode.  You may increase the Watch Dog Timer setup.  

2 One Shot: Select the One Shot by clicking the check box. If One Shot is selected, the For-Next Loop will be processed (all loops) one time after being enabled. The For-Next Loop will not be executed again until there is another OFF-to-ON transition by the enabling contact.

Example Program

Example Program: For-Next Loop

In the following example, when X001 is ON, the Ladder Program is executed 100 times in one same program scan.

Related Topics:

Next Instruction