Siemens SIMATIC S5 Manual page 271

Reaction times in the ET 200 distributed I/O system
C.1.2 Reaction time t
Definition
Importance
C-4
cons
t is the reaction time for data transfer between CPU and IM 308-C.
cons
Figure C-2 Reaction time t
As regards accessing the process image, t
only if:
in the application program, you access I/O directly
and
the CPU reads or writes a consistent area.
In this case you can refer to the table below for values of t
Table C-3 Reaction time t
CPU t
cons
941A
941B
942A
942B
943A
943B
944A
t
cons
cons
is negligible. t
cons
cons
in ms CPU
12.6 944B
5.5 945
12.2 922
5.5 928A
6.6 928B
5.5 946/947
0.6 948
is important
cons
:
cons
t in ms
cons
0.5
0.1
3.3
2.2
0.4
0.4
0.2
ET 200 Distributed I/O System
EWA 4NEB 780 6000-02a