Step7, Using Free Channels On An Existing Module - Siemens SIMATIC S7-400H System Manual

System modifications during operation
17.5 Adding components in STEP 7
17.5.9

STEP7, Using 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
● Modules in switched DP stations are not reconfigured when you switch over to the CPU
Proceed as follows to change the channel use:
● In steps 1 to 5, you completely remove the respective module from the hardware
● In steps 3 to 8, you add the module with the modified use once again to the hardware
310
substitute or hold values).
with the modified configuration.
configuration and the user program. But it can remain inserted in the DP station.
configuration and the user program.
NOTICE
The respective modules are not addressed between the two changeover steps (steps V
and 6); respective output modules output the value 0.
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.
System Manual, 03/2012, A5E00267695-11
S7-400H