Using Single-Channel, One-Sided I/O; What Is Single-Channel, One-Way I/O?; Single-Channel, One-Way I/O Configuration - Siemens SIMATIC S7-400H Manual

7.2

Using Single-Channel, One-Sided I/O

What is single-channel, one-way I/O?

With the single-channel, one-way configuration single input/output modules are
present (single-channel). The input/output modules are located in just one of the
subsystems and are only addressed by that subsystem.
A single-channel, one-way I/O configuration is possible in
• central controllers and expansion units
• distributed I/Os
The single-channel, one-way I/O configuration is to be recommended for individual
input/output channels for which normal availability of the I/O is sufficient.
Figure 7-1
Automation System S7-400H Fault-tolerant Systems
A5E00068197-07
Rack 0 Rack 1

Single-channel, one-way I/O configuration

Using I/O on the S7-400H
Single-channel, one-way I/O
modules in the central controller
Single-channel, one-way
distributed I/O, say ET 200B
7-3