Siemens SIMATIC S7-GRAPH - Programming the Structure of the Sequencer; Sequencer - Principle

S7-GRAPH for S7-300/400 Programming Sequential Control Systems
C79000-G7076-C526-01
6-1
6 Programming the Structure of the
Sequencer
Aims
The section below explains the rules and elements for creating a sequencer.
OB/FB/FC
DB i
T2
T1
S2
S1
Comment for ...
FB i
CALL FBi,Dbi
SQ_INIT:=
(1)
(2)
(3)
(4)
(5)
The heart of a sequential control system is made up of the S7-Graph FBs (1).
These contain the following:
• The program for step by step execution of the controller in sequencers (4).
• Permanent instructions (3)(5) that are valid for all sequencers of the FB (and
are displayed in a separate window)
• A block comment (2) with which you can describe the entire block.