When you configure the Smart HART Discrete Input function block, you select the I/O channel associated with the discrete measurement by configuring the Device Signal Tag (DST) of the IO_IN parameter to one of the Smart HART Discrete input variables as shown below. Note that HART_DV_DIn can only be bound to the IO_IN parameter of the SHDI block.
SIMULATE_IN_D is a STATE value from the list of named set codes for SHDI and SHDO blocks.