Characteristic Data Of Fdl Communication - Siemens CM 1542-5 Operating Instructions Manual

Product overview, functions
2.4 Configuration limits and performance data
DP startup behavior
Note
Increasing the default value for startup parameters - configuration of the CPU
In some situations, it is necessary to increase the default value for the startup parameter
"Parameter assignment time for the distributed I/O" in the configuration of the CPU:
• A large number of modules (DP slaves) is configured.
• When a high value is configured for the constant bus cycle time in the network properties
of the PROFIBUS DP line.
2.4.4

Characteristic data of FDL communication

Characteristic data FDL
The characteristic data is important when operating FDL connections (specified, free layer 2
(SDA and SDN), broadcast, multicast):
Table 2- 2 Characteristic data FDL
Characteristic
Total number of FDL connections that can
be operated
Size of the transferable data area for FDL
connections
Note
Connection resources of the CPU
Depending on the CPU type, different numbers of connection resources are available. The
number of connection resources is the decisive factor for the number of configurable
connections. For this reason, lower values than specified here can result.
You will find detailed information on the topic of connection resources in the
"Communication" function manual, see Communication
(http://support.automation.siemens.com/WW/view/en/59192925).
16
Explanation / values
30 max.
1...240 bytes max. per specified FDL connection (for sending and receiv-
•
ing):
Free layer 2 broadcast and multicast:
•
Up to 236 bytes of user data can be transferred per job. The job header
occupies an additional 4 bytes.
Operating Instructions, 11/2018, C79000-G8976-C290-04
CM 1542-5