Siemens CPU 948 User Manual

10.3 Runtimes of the Communication OBs
The "runtime" is the processing time of the special function
organization blocks; the time from calling a block to its termination
can be much greater if it is interrupted by higher priority activities
(e.g. updating timers, etc.).
Special function OB
Block
name
CPU 922 CPU 928 CPU 928B CPU 946/
947
CPU 948
OB 200/
initialize
230 ms 130 ms 130 ms 128 ms 90 ms
OB 202/
send
806 µs (294 µs
basic time
+ 16 µs/word);
118 µs if a
warning occurs
666 µs (250 µs
basic time
+ 13 µs/word);
115 µs if a
warning occurs
696 µs (280 µs
basic time
+ 13 µs/word);
145 µs if a
warning occurs
762 µs (426 µs
basic time
+ 21 µs/
double word);
243 µs if a
warning occurs
542 µs (220 µs
basic time
+ 19 µs/
double word);
110 µs if a
warning occurs
OB 203/ send test
72 µs 50 µs 80 µs207µs 115 µs
OB 204/ receive
825 µs (281 µs
basic time
+ 17 µs/word);
115 µs if a
warning occurs
660 µs (244 µs
basic time
+ 13 µs/word);
98 µs if a
warning occurs
690 µs (274 µs
basic time
+ 13 µs/word);
128 µs if a
warning occurs
772 µs (421 µs
basic time
+ 22 µs/
double word);
243 µs if a
warning occurs
506 µs (218 µs
basic time
+ 18 µs/
double word);
132 µs if a
warning occurs
OB 205/
receive test
70 µs 48 µs78 µs 223 µs 120 µs
The runtimes listed in table 10-6 assume that of four CPUs inserted in
a rack, only the CPU whose runtimes are being measured accesses the
SIMATIC S5 bus. If other CPUs use the bus intensively, the runtime
increases particularly for the send/receive functions.
Table 10-6 Runtimes of the communication OBs
Runtimes of the Communication OBs
CPU 948 Programming Guide
C79000-G8576-C848-04
10 - 31

Siemens CPU 948 Specifications

General

Brand	Siemens
Model	CPU 948
Category	Controller
Language	English