Upon the occurrence of an event at the REQ input, an instance of this FB type sets the OUT value to the position of the first byte of the first occurrence of the value of the IN2 input in the IN1 input and issues an event at the CNF output.

• Following the IEC 61131-3 convention, the index of the leftmost byte position is 1.
• OUT = 0 indicates that there is no occurrence of IN2 in IN1.