Configuration Limits And Performance Data; Configuration Limits - Number Of Cms - Siemens CM 1542-5 Operating Instructions Manual

Product overview, functions

2.4 Configuration limits and performance data

Time-of-day synchronization - time master or time slave
The CM 1542-5 can be enabled for time-of-day synchronization. As an alternative, the CM
can be configured as time master or time slave on PROFIBUS.
● Time master: The CM is synchronized using the time of day in the S7-1500 station and
outputs the time of day on PROFIBUS. The output interval can be set.
● Time slave: The CM receives time-of-day frames on PROFIBUS and outputs the time
within the S7-1500 station. The output interval within the S7-1500 station is set
permanently to 10 seconds.
Note
Recommendation for setting the time
It is advisable to set the time-of-day master so that time-of-day frames are sent at intervals of
approximately 10 seconds. This achieves as small a deviation as possible between the
internal time and the absolute time.
Web diagnostics
With the aid of Web diagnostics of the CPU, you read the diagnostics data from an S7
station via the Web browser on the PG/PC.
In terms of the CM, the Web pages provide the following information:
● Module and status information
● Special information on the DP master system (status of the DP slaves)
2.4 Configuration limits and performance data
2.4.1

Configuration limits - number of CMs

When using the CM type described here, the following limits apply:
● The number of CMs that can be operated in a rack depends on the CPU type being used.
Refer to the information in the system manual (hardware configuration), see Guide to the
documentation (Page 9).
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Operating Instructions, 11/2018, C79000-G8976-C290-04
CM 1542-5