Siemens SIMATIC C7-621 Manual page 14

Introduction
The general functions also correspond to a configuration with standard
modules from the PLC and OP ranges. The individual components operate
independently of each other and each processor has its own memory.
The C7 CPU is programmed with STEP 7 and the C7 OP is configured with
ProTool/Lite. The software runs under Windows 95 on a programming device
or PC.
Figure 1-2
1-8
C7-621 AS-i
CPU memory
C7 CPU
C7 CPU
C7 AS-i
P bus
Components of the C7-621 AS-i
OP memory
C7 OP
MPI
interface
STEP 7
ProTool Lite
or
ProTool
C7-621 / C7-621 AS-i Control Systems
C79000-G7076-C622-01
C7 OP