Siemens SINUMERIK 880 SW 6 Planning Manual page 165

5 Description of Basic Signals (FY 0 ... FY 24)
5.1 PLC auxiliary signals
INITIAL SETTING (OB 1 to OB 7)
1 signal: A warm restart has taken place. The processing level of the relevant OB is called
for the first time after the warm restart.
0 signal: The relevant OB has been fully executed at least once since the last warm restart.
After a PLC warm restart the initial setting signals are set for the duration of the first complete
program execution of the relevant processing plane.
After the first complete execution of the relevant processing plane the initial setting signals are
reset to zero by the PLC operating system.
Note on application:
These signals can be used to obtain a defined initial setting for program parts after Power On.
For example, an initialization routine can be called in every OB depending on the initial setting
signals.
Notes:
• Processing level interrupted by Power Off:
The initial setting signal of the processing plane interrupted by the power failure (e.g.
owing to Power Off) is not immediately set with the warm restart. The initial setting signal
for this processing level is set after the remaining execution of the processing level so that
it is set for the duration of the next execution of the relevant OB.
The initial setting signal for an OB is not, therefore, set while the relevant processing level
is active.
• Several processing levels active with Power Off:
If several processing levels were active when the program was interrupted (e.g. owing to
Power Off), their initial setting signals are not set until the remainder of all the interrupted
processing levels has been executed following the warm restart. This is explained in
greater detail in the following example.
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1) If using a SIMATIC S5-155U, refer to SINUMERIK 880 with S5-155U, Difference Description to PLC 135 WB in
this context.
5–2
1)
© Siemens AG 1991 All Rights Reserved
05.91
FY 2, bit 1 to 7
6ZB5 410-0HE02
SINUMERIK 880 (PJ)