The SEQ function block associates system states with actions. The combination of STD blocks (which associate transitions with states you define) and SEQ blocks provide a sequencing capability similar to DeltaV Sequential Function Charts (SFC).
The SEQ block can have as many as 16 states and 16 discrete outputs. For each state, the block sets the value of the outputs based on the pattern defined by the MATRIX parameter. The block can step through the states in sequence using internal increment and decrement parameters, or the block can be set to specific states (and the corresponding outputs set) from logic external to the block.
The SEQ block does not support modes or alarm detection.
The following diagram shows the internal components of the Sequencer function block.
