The DeltaV system utilizes modular configuration for developing a control strategy. The control modules are treated as unique, named control entities in the DeltaV system. The function block is the basic component of a control module, that is, it is the building block of the control module. Each function block contains standard process control algorithms (such as PID, Analog Out, and Analog In) and parameters that customize the algorithm.
Function block algorithms range from simple input conversions to complex control strategies. The function block uses parameter data supplied by the user, by the function block itself, or by other function blocks to perform its calculations and logic functions and to supply an output value to other function blocks or to field devices. Some function blocks also detect alarm conditions.
You can connect function blocks together in a control module function block diagram so that data can be transmitted between blocks. This data can be used in the control algorithm, mathematical or logical calculation, or status determination of the block. This capability helps you implement a variety of process control strategies, including advanced control, shutdown sequences, and process reactions to quality control information.