Settings On The Coordinator; User Control - Siemens S5-155U System Manual

6.4.2
Settings on the
Coordinator

User control

System Manual
C79000-B8576-C199-03
Communication memory
The communication memory comprises a central battery-backed RAM
in the PLC. It has two areas: the communication flags and the
semaphores.
The communication flags on the COR 923A allow the cyclic
interchange of data between the CPUs. The semaphores are mainly
used to coordinate the exchange of data in the I/O area.
Please consult the Programming Guides of the CPUs to program these
functions.
A three-stage mode switch on the front plate serves for user control; it
has the settings RUN, STOP and TEST.
The functions of the mode switch and its use are explained in
Sections 6-2 and 6-3.
Mode Switch for
RUN, STOP and TEST
Figure 6-6 Front Plate of the COR 923A
923A Coordinator Module
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