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Introduction to STEP 5
Calculating the Maximum Response Time of the External I/Os
Figure 7-12 shows a schematic of the S5-95F program processing.
Delay time of
the onboard DI
OBP
read2
Program
...
ExP1
processing
Input signal changes;
signal change is not yet
recognized during ExP1
Figure 7-12. Response Time of the External I/Os (Worst Case)
You calculate the maximum response time T
external I/Os as follows:
T
=
OB1 response, ExP
+ 2 x operating system runtime (80 ms)*
+ 1 x data cycle time of the external I/Os (max. 7 ms)
+ 1 x delay time of the input modules (5 ms)
Expressed in OB1 cycles, the following applies:
T
=
OB1 reponse, ExP
+ 1 x delay time of the input modules (5 ms)
+ 1 x data cycle time of the external I/Os (max. 7 ms)
The integrated cycle time statistics (see section 15.7) are an aid enabling you to initially assess the
cycle time
Extension of the Response Time through STATUS Programmer Function
Note
During the STATUS programmer function, the S5-95F processes the blocks in a special
mode; the runtime of the blocks increases considerably and is command-dependent.
Please note that this also results in an increase in the response time. Therefore program
your blocks as short as possible.
* Times increase in the case of loading through interrupts or programmer operation (see section 7.4.2)..
7-24
OBP
OBP
write2
...
ExP2
Besy
Input signal change
is recognized during ExP2
2 x program processing time
2 x OB1 cycle time
ExP:
Besy:
OBP
: Read cycle of the onboard I/Os
read
OBP
: Write cycle of the onboard I/Os
write
OBP
read3
write3
Program
...
processing
Besy
with cyclical program processing via the
OB1 response
Data cycle of the external I/Os
Operating system
OBP
read4
Program
ExP3
processing
Response to input
signal change during ExP3
EWA 4NEB 812 6210-02
S5-95F
t
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