Siemens SIMATIC ET 200M Operating Instructions Manual page 267

Time stampingTime stamping
Specifies date and time in messages.
If configured for time stamping, binary input signals are time-stamped when changes occur.
After they have been changed all configured binary input signals must be time-stamped at a
preset accuracy level, such as 10 ms, across the entire system. Therefore, when 2 sensors
(from two different stations) are triggered simultaneously in different PROFIBUS DP master
systems, the time stamp difference for these signal changes must not exceed the preset
accuracy (10 ms in this case).
Time stampingTime stamping
Specifies date and time in messages.
If configured for time stamping, binary input signals are time-stamped when changes occur.
After they have been changed all configured binary input signals must be time-stamped at a
preset accuracy level, such as 10 ms, across the entire system. Therefore, when 2 sensors
(from two different stations) are triggered simultaneously in different PROFIBUS DP master
systems, the time stamp difference for these signal changes must not exceed the preset
accuracy (10 ms in this case).
Time synchronization
Time synchronization ensures that all clocks in a system are set to the same time. In
addition, in a configured cycle, a time master distributes the time to all the other components
in the automation system that possess a clock. The components then use the distributed
time to set their respective clocks.
Update
After performance or (compatible) function enhancements you should update the interface
module IM 153-2 to the latest firmware version.
ET 200M
Operating Instructions, 12/2008, EWA-4NEB780600602-08
Glossary
265