Basic Data For S7 Communication; Using Parallel Communications Services (Multiprotocol Operation) - Siemens CP 342–5 Manual

1.2.5

Basic Data for S7 Communication

The following characteristic data are important for operating S7 connections:
Table 1-8
Feature
Number of S7 connections that can be operated
1) The actual number of S7 connections that can be operated depends on the CPU type you are using. There
are further restrictions if you operate in mixed mode. Refer to Section 1.2.6 for more information.
1.2.6 Using Parallel Communications Services (Multiprotocol Opera-
tion)
Performance
If you want to use the available communications services at the same time, there
are restrictions in terms of communication performance.
The following table shows the transmission rate for FDL connections dependent on
the following:
S The frame length (number of bytes)
S The number of connections
The values were measured when sending and receiving in direct succession (at a
transmission rate of 1.5 Mbps, bus profile universal, two stations, mode "no DP").
Table 1-9 Number of FDL Frames per Second
Number of
connections
Frame length
1 byte
100 bytes
240 bytes
Note
Recommendation: In the mixed mode – DP + FDL + S7 functions – a delay time
should be selected.
12
16 maximum
1 4
77 / s 92 / s
73 / s 88 / s
67 / s 82 / s
Explanation / Values
1)
8 16
92 / s 92 / s
88 / s 88 / s
83 / s 84 / s
Manual CP 342–5 / CP 342–5 FO
C79000–G8976–C146/01