The Off-Delay Timer (OFFD) function block delays the transfer of a False (0) discrete input value to the output by a specified time period. The block supports signal status propagation. There are no modes or alarm detection in the Off-Delay Timer function block.
IN_D is the discrete input value and status used to trigger the timed discrete output value.
OUT_D is the discrete output value and status.
The Off-Delay Timer function block immediately transfers the discrete input value (IN_D) to the output (OUT_D) when IN_D is True (1). When IN_D transitions to False (0), OUT_D is reset to False after a specified time period (TIME_DURATION). During this time period, ELAPSED_TIMER tracks the time starting when IN_D transitions to False until the time specified by TIME_DURATION expires.
The following figure shows the internal components of the Off-Delay Timer function block:
