Siemens SIMATIC S7-GRAPH Manual page 169

OB 1
(cyclic)
The various functions at the individual levels are executed cyclically in the order in
which they are called:
• The sequencers are preceded by the central, higher-level functions of the cell
level.
• The various sequencers for the individual stations are called by an FB
"Sequencers" that is called in OB1.
• The program sections for manual mode, the interlocks and permanent
monitoring functions for the units follow the sequencers.
• If the manufacturing cell includes robots, program sections for supplying and
clearing robot interface are also required.
Enabling Operation
In production facilities, utilities such as hydraulic and pneumatic systems are often
required and the functions of all other units depend on them being available. It
therefore makes sense to turn on the hydraulic and pneumatic systems centrally
after turning on the machinery and to generate ready signals for the other blocks.
The following diagram is an example of how general operation of the system can
be enabled in S7-Graph.
S7-GRAPH for S7-300/400 Programming Sequential Control Systems
C79000-G7076-C526-01
General
Release operation
functions
Sequencers
Station 1
Insert, weld
Manual mode,
Hydraulics
Interlocks
Pneumatics
Poss. robot
interface
Notes on Configuration
Modes
Station n Save
Station 1 Turn
Unit station n
Unit station 1
14-3