Introduction - Siemens S5-155U System Manual

Introduction

6.1

Introduction

Slots occupied
Coordinator
6 - 4
The S5-135U/155U is a member of the SIMATIC S5 family of
programmable (logic) controllers. The PLC can be used both in single
and in multiprocessor operation with up to four CPUs.
You can arbitrarily combine the CPUs in the central controller at the
CPU slots.
CPU
CPU 948/CPU 928B/CPU 928
CPU 922
In multiprocessor operation, each CPU processes its individual user
program independently of the other CPUs.
The common S5 bus serves for data interchange with I/O modules,
CPs, IPs and other CPUs. In multiprocessor operation, access of the
CPUs to the S5 bus is controlled by a coordinator. The functioning of
this module is described in Sections 6.5 and 6.6.
For an explanation of data interchange between CPUs in
multiprocessor operation and the arrangement of your STEP 5
program, please consult the Programming Guide for your CPU.
A coordinator is required in multiprocessor operation. The following
are available for the S5-135U/155U PLC:
• • 923A coordinator (COR A)
and
• • 923C coordinator (COR C).
The coordinator allocates to the CPUs the time divisions in which they
can access the S5 bus (bus enable time), and contains the global
memory for data interchange between the CPUs via communication
flags. Additionally, the COR C contains another memory with four
pages for the "multiprocessor communication" function as well as a
serial PG interface with PG multiplexer function (PG MUX).
Slot Requirement
2 slots
1 slot
System Manual
C79000-B8576-C199-03