The Fieldbus Multiple Discrete Input (FFMDI) function block combines the eight channels of a Discrete Input card and makes them available as an 8-bit input to other function blocks.
This block must be assigned to an H1 Carrier device. The carrier supports one Discrete Output and one Discrete Input card. The H1 Carrier Multiple Discrete Input block processes the discrete input values of multiple devices through a Discrete Input card connected to the carrier. Using the H1 Carrier Multiple Discrete Input block assigned to the carrier enables multiple discrete devices to communicate back to the DeltaV controller through the H1 fieldbus rather than through conventional wiring.
The H1 Carrier Multiple Discrete Input function block supports mode control, signal status propagation, and simulation.
Normally, the block is used in Automatic (Auto) mode so that the process variable (PV_D) is copied to the output (OUT_INT). You can change the mode to Manual (Man) and substitute a manually entered value for OUT_INT. In this case, PV_D continues to show the value that will become OUT_INT when the mode is changed to Auto.
OUT_INT is the 8-bit integer output value and status.
The following diagram shows the internal components of the H1 Carrier Multiple Discrete Input function block:
