The first time the function block is executed (when loading the program or during online calls), all the values contained in the BUFFER are initialized with the value of TR_I. The OUT output retains this value for the duration of the T_DELAY. If the TR_I input is not attached, the value 0 serves to initialize the BUFFER output and the OUT output retains the value 0 during the T_DELAY.

In the tracking operating mode (TR_S = 1) the input TR_I is transferred to the output OUT and the BUFFER output is also initialized with the value of TR_I. After returning to normal operating mode, the output retains this value for the duration of T_DELAY, as was the case with the first cycle.