Startup And Synchronization Of Nck Plc - Siemens SINUMERIK 840D sl Function Manual

P3: Basic PLC program for SINUMERIK 840D sl
13.10 Structure and functions of the basic program
Figure 13-10 Structure of the basic program (principle)
13.10.1

Startup and synchronization of NCK PLC

Loading the basic program
The basic program must be loaded with the S7 tool when the PLC is in the Stop state. This
ensures that all blocks in the basic program will be initiated correctly the next time they are
called. Otherwise, undefined states can occur in the PLC (e.g. blinking of all PLC LEDs).
Startup,
The synchronization of NCK and PLC is performed during startup. The system and user data
blocks are checked for integrity and the most important basic program parameters are verified
for plausibility. In cases of errors, the basic program produces an alarm (visible on HMI) and
switches the PLC to the Stop state.
A warm restart is not provided, i.e. following system initialization, the operating system runs
organization block OB100 and always commences cyclic execution at the start of OB1.
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Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Basic Functions