Performance data and behavior in operation
5.5 Characteristics of S7 communication
CP 342-5 / CP 342-5 FO
Manual, 10/2011, C79000-G8976-C146-09
29
Execution times for program blocks for S7 connections
The following table will help you to calculate the CPU cycle times (OB1) for S7 connections.
The table contains the execution time of the program blocks (PUT, GET, USEND, URCV,
BSEND, BRCV) required for DP processing on the S7-300 / C7-300 CPU.
Execution time on the CPU per block call
Block type
PUT
GET
USEND
URCV
BSEND
BRCV
Data length
<=160 bytes
<=16 K bytes
CPU 314C-2DP
(6ES7 314-
6CF00-0AB0)
<5.6 ms <5.8 ms
<6.0 ms
<5.6 ms
<5.7 ms
<5.8 ms
CPU 317-
2PN/DP (6ES7
317-2EJ10-
0AB0)
<2.1 ms <2.5 ms
<2.0 ms
<2.4 ms
<2.1 ms
<2.7 ms
Time response on S7 connections
Refer to the following table for transmission rates with S7 connections dependent on the
following parameters:
●
Frame length (number of bytes)
●
Job type
●
CPU type
The values were measured while sending or receiving successively (at a transmission rate of
1.5 Mbps; bus profile standard; 9 nodes).
Table 5- 2
Number of S7 frames per second for CPU 317
Request type
Frame length
Number of S7 frames per
second
PUT
<=160 bytes
29 / s
GET
<=160 bytes
26 / s
USEND/URCV
<=160 bytes
35 / s
<=160 bytes
25 / s
<=400 bytes
14 / s
BSEND/BRCV
<=800 bytes
8 / s
