This Function Block type is used to demonstrate the handling of self-cycles when editing Execution Control Charts (ECCs).

The operation of an instance of this type is defined by the ECC shown above, in conjunction with the following algorithms.

ALGORITHM ZERO IN ST : (* Initialize SUM *)
SUM := 0;
END_ALGORITHM

ALGORITHM ADDIT IN ST : (* Add 1 to SUM *)
SUM := SUM + 1;
END_ALGORITHM