User Manual

Logic Functions - Book 2
SEQUENCE BLOCK
10-2
The Sequence Block allows up to:
• 128 inputs
• 64 outputs
• 512 steps
Sequence blocks can be linked together to increase input/output capacity using an External
Step Source attribute which is configurable in each block.
10.3 SEQUENCE BLOCK OPERATION
A functional block diagram, Figure 10-1, shows basic input/output structures and signal logic
flow for the block (signal flow is left to right top to bottom). Attributes are shown as selectable
signal flow paths or as possible values to the specified attribute in the attribute box. When a
logical source pointer (LSP) is selected, the data source becomes a softwired connection in
the instrument. The following conventions are used in presenting the database block diagram.
• Data Base Attributes Shown in solid boxes
• Internal functions Shown in dashed boxes
The sequence block processes a group of inputs to produce a group of outputs which are
selectively active on a sequential basis in a series of steps. The basic operational functions of
the block are:
• Input processing
• Transition Expression Evaluation
• Step Determination
• Output Management
• Quality Checking