Reaction Times; B4A−33; Cp 443-1 Advanced For Industrial Ethernet / Manual Part B4A; Release 01/2007 B4A−3 - Siemens CP 443-1 Manual

5.6.3

Reaction Times

Definition
The reaction time is the time from recognizing an input signal until the associated
output signal changes.
Influences
The actual reaction time is subject to certain fluctuations. The achievable reaction
times for PROFINET CBA communication depend on the following factors:
S Type of interconnection (cyclic or acyclic) and the transmission frequency or
scanning frequency;
S The size of the configuration on the component interface (size of the interface
DB for PROFINET CBA);
S CPU cycle time and CPU type;
S Parallel operations with other types of communication types such as
PROFINET IO or with services such as online monitoring.
As a result, the reaction times for cyclic PROFINET CBA interconnections may
exceed the configured value for the transfer frequency. You should therefore check
the reaction time that can be achieved during commissioning and, if necessary,
change the project engineering.
Measurements in a Sample Configuration
Measurements were made to help you to estimate the influence of the configured
transfer frequency and the configuration (interface DB) with cyclic PROFINET CBA
interconnections.
These measured results relate to a certain sample configuration. Two S7−400
stations were used each with a CP 443−1 Advanced. FB90 was used in the user
program (FB90 has better time characteristics than FB88).
S7−400 station 1
CPU 416-2
CP 443−1 Advanced
Measurement principle:
Output data is generated by station 1 and interconnected as input data with station

CP 443-1 Advanced for Industrial Ethernet / Manual Part B4A

Release 01/2007
C79000-G8976-C193-06
5 Performance Data
S7−400 station 2
CPU 416-2
CP 443−1 Advanced
B4A−33