Siemens SIMATIC ET 200M Operating Instructions Manual page 177

Time when using active bus modules
Note
With IM 153-2 (6ES7153-2BAxx-0XB0) the use of active bus modules for an isochronic
operation is not intended as the synchronization conditions for this application case are only
fulfilled module-granular.
However, if active bus modules are to be used, the user must incorporate in each case a
time of 0.5 ms for Ti and To and therefore an equidistant DP cycle of 1 ms.
Additional information
For further information about the isochronous mode please refer to the
and the "Isochronous (http://support.automation.siemens.com/WW/view/en/15218045)"
Function Manual.
8.7 Identification and maintenance data (I&M data)
Definition and properties
Identification and maintenance data (I&M) are data that are stored in a module for assisting
you in:
● Checking the system configuration
● Locating hardware changes in a system
● troubleshooting a system
Identification data (I data) is information regarding the module, like for example, order
number and serial number, which are partly also printed on the housing of the module. I data
is manufacturer´s information on the module and can only be read.
Maintenance data (M data) is system-dependent information, like for example, location and
date of location. M data is created during the configuration and written to the module.
The modules can be uniquely identified in online mode by means of the I&M data.
ET 200M
Operating Instructions, 12/2008, EWA-4NEB780600602-08
8.7 Identification and maintenance data (I&M data)
Functions
STEP 7
Online Help
175