Saving and Compiling
S7-GRAPH for S7 300/400 Programming Sequential Control Systems
8-6
C79000-G7076-C526-01
Interface Description
The interface description decides how data for steps and transitions are created in
the instance DB.
•
Structure
arrays:
The interface descriptions are created in the instance DB as ARRAYs. This
option optimizes the memory requirements of your S7-Graph FB. The step
names are, however, not stored. Symbolic addressing of other blocks is not
possible in this case.
•
Individual
structures:
The interface descriptions are stored in the instance DB as structures
(STRUCT). A separate structure with detailed information is created for each
step and each transition of the sequencer. This is a convenient method allowing
internal and external access using symbolic names. The instance DB can be
evaluated both by direct access to the data fields or using the step and
transition names. The structures increase the size of the instance DB but do not
affect the performance when executing the sequencer.
•
Download interface description to PLC:
If you select this option, the interface description is downloaded to the PLC
when you download an FB with S7-Graph. This allows you to decompile the
block on a programming device on which the suitable project structure is
available.
Sequencer Properties
Sequencer properties influence the way in which sequencers are operated.
•
Criteria analysis data in the DB:
The data required for criteria analysis are written as additional information to the
instance DB. They contain a compact form of the condition descriptions of the
sequencer.
•
Skip
Steps
If both the transition before the step and the transition after the step are valid at
the same time, the step does not become active and is skipped.