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Programming the Structure of the Sequencer
S7-GRAPH for S7 300/400 Programming Sequential Control Systems
6-10
C79000-G7076-C526-01
6.11
Permanent Instructions
Permanent instructions are conditions (1) and block calls (2) located before or after
the sequencer. These are executed once per scan cycle regardless of the state of
the sequencer.
You can program any number of permanent instructions in an S7-Graph FB. Each
permanent instruction is assigned a number.
You program permanent instructions in a separate window in the "Permanent
Instructions" view.
I 2.3
I 2.5
M2.0
I 0.0
CALL
1
2
(1)
(2)
Permanent Condition
Conditions that must be satisfied at more than one point in the sequencers can be
programmed once centrally as permanent conditions. You can use the Ladder
Logic elements: normally-open contact, normally-closed contact, and comparator
or the FBD elements AND box, OR box, and comparator. A maximum of
32 Ladder Logic/FBD elements can be programmed per permanent condition.
The result of combining the conditions is stored in a ladder coil or in an FBD
assignment with which the functions set and reset are available. The address used
(for example a memory bit) can be queried in a transition, interlock, and
supervision.