Siemens SIMATIC NET CP 1604 - What Types of IO Routing Exist; How Does the IO Router Work

Operating hardware
4.3 IO routing
CP 1604 / CP 1616
Operating Instructions, 02/2017, C70000-G8976-C218-08
69
4.3.2
What types of IO routing exist?
Read and write
From the perspective of the IO controller for the control level, there are three IO routing
tasks:
● Read process inputs
● Write process outputs
● Read process outputs
Read process inputs
Inputs are always read module-oriented.
This means that the IO controller for the control level (and the IO controller for the process
level) can only ever read
all
bits of a module.
Write process outputs
When writing process outputs, on the other hand, there are two possible ways of writing:
●
Writing module-oriented
All
process outputs of a module are written by the IO controller for the control level
(module-oriented).
●
Writing bit-oriented
Individual
configured process output bits or bit areas are written by the IO controller for
the control level.
Read process outputs
Outputs are always read module-oriented.
This means that the IO controller for the control level can only ever read
all
bits of a module.
4.3.3
How does the IO router work?
Requirements
A CP 1616 or CP 1604 communications processor is required in a PC station. Only these
CPs can be both IO controller and IO device at the same time.
Configuration
The CP is first configured as an IO controller. Its
process controller user program
controls
the IO devices assigned to it on the Ethernet bus.