Notes on Configuration
S7-GRAPH for S7-300/400 Programming Sequential Control Systems
C79000-G7076-C526-01
14-5
•
If an OK signal from one of the power systems is canceled while the
Process_enabled (step 4) is active, the enable signals are also canceled with
the change to step 2. Once the OK_Signals of the power systems are present
again, Central_start can return the unit to the enabled state again.
•
The signals "Controller_on", "Unit_ready" and "Process_enabled" are sent to
the other blocks and the central controller.
•
The signal "Unit_ready" also enables the mode selection in the mode block.
•
The "Process_enabled" signal enables the automatic mode.
Handling Modes
Depending on the situation, the user requires different modes for the system and
machinery. In unlinked manufacturing cells, for example in body work assembly,
these are the modes:
•
Automatic
•
Inching, in other words a variant of the automatic mode with a stoppage after
each process step
•
Automatic or switch to next; in other words the automatic mode with an addition
step enabling condition
•
Manual/setup, in other words direct influence on the units or functions
The modes, however, do not have the same effects at all levels. The following
overview lists the modes and their effects at the coordination level and unit level
(motors, valves etc.).
Mode
Effect at the coordination level
Effect at the unit level
Automatic
=> Sequencer switches to next step
when the transition is satisfied.
=> Enabling of the drive by the
sequencer
Inching
=> The sequencer switches to the next
step when the transition is satisfied
and the "Inching" button signal
enables the next step.
=> Enabling of the drive by the
sequencer
Automatic
or step
by step
mode
=> The sequencer progresses when
the transition is satisfied or the
"Inching" button signal enables the
next step.
=> Enabling of the drive by the
sequencer
Manual or
setup
=> Enabling of next step suppressed,
the status of the sequencer has no
effects at the unit level.
=> Drive enabled by direction
buttons