Use Of Free Channels On An Existing Module - Siemens SIMATIC PCS 7 CPU 410-5H System Manual

System modifications during redundant operation
10.3 Adding components
10.3.8

Use of free channels on an existing module

The use of previously free channels of an I/O module depends mainly on the fact if the
module can be configured or not.
Non-configurable modules
Free channels can be switched and used in the user program at any time in case of non-
configurable modules.
Configurable modules
The hardware configuration first has to be matched to the used sensors or actuators for
configurable modules. This step usually requires a new configuration of the entire module in
most cases.
This means an uninterrupted operation of the respective modules is no longer possible:
● One-sided output modules briefly output 0 during this time (instead of the configured
substitute or hold values).
● Modules in switched DP stations are not reconfigured when you switch over to the CPU
with the modified configuration.
Proceed as follows to change the channel use:
● In steps 1 to 5, you completely remove the respective module from the hardware
configuration and the user program. But it can remain inserted in the DP station. The
module drivers must not be removed.
● In steps 2 to 7, you add the module with the modified use once again to the hardware
configuration and the user program.
Note
The respective modules are not addressed between the two changeover steps (step 5);
respective output modules output the value 0. The existing channel drivers in the user
program hold their signals.
If this behavior is unacceptable for the process to be controlled, there is no other way to
use previously free channels. In this case you must install additional modules to expand
the system.
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CPU 410-5H Process Automation
System Manual, 09/2014, A5E31622160-AB