Installation Rules; Configuring Hardware; Special Features In Presenting The Hardware Configuration - Siemens SIMATIC S7-400H Manual

Configuring with STEP 7

Installation rules

• A fault-tolerant station may contain up to 20 expansion racks.
• Even-numbered mounting racks can be assigned only to central controller 0,
whereas odd-numbered mounting racks can be assigned only to central
controller 1.
• Modules connected to a communication bus can be operated only in mounting
racks 0 through 6.
• Communication-bus capable modules are not permissible in switched I/Os.
• Pay attention to the mounting rack numbers when operating CPs for
fault-tolerant communications in expansion racks:
The numbers must be directly sequential and begin with the even number – for
example, mounting racks numbers 2 and 3, but not mounting racks numbers 3
and 4.
• A mounting rack number is also assigned for DP master No. 9 onwards when
equipping a central controller with DP master modules. The number of possible
expansion racks is reduced as a result.
Compliance with the rules is monitored automatically by STEP 7 and taken into
account in an appropriate manner during configuration.
9.2.2

Configuring Hardware

The simplest way of achieving a redundant hardware configuration consists in
initially equipping one mounting rack fully with all the redundant components,
assigning parameters to them and then copying them.
You can then specify the various addresses (for one-way I/O only!) and arrange
other, non-redundant modules in individual racks.

Special features in presenting the hardware configuration

To make it possible for a redundant DP master system to be detected quickly, it is
represented by two closely parallel DP cables.
9-4
Automation System S7-400H Fault-tolerant Systems
A5E00068197-07