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S5-115F Manual
10.3.1 Response Time in the Case of Cyclical Reading In and Output via the
Process I/O Image
If input signals are read in via the process input image (PII) (e.g. using the A I 1.0 operation), and
the response is output via the process output image (PIQ) (e.g. using the S Q 4.0 operation), this
results in the following response time:
T
2 * T
R
PLC cycle
OS
OS
after
before
user
user
prog.
prog.
Figure 10-1. Response Time in the Case of Cyclic Read-In of Process Signals
Explanation of Figure 10-1
If input signal
changes during the user program, the change is recognized in the next PLC cycle
when this signal is read in . The user program processes the input signal and triggers the output
response in the operating system .
10.3.2 Response Time in the Case of Direct Access in the Cyclic Program
If the input signal is read from the input module by direct access (e.g. using the L PW operation)
and the response is output by direct access to the output module (e.g. using the T PW operation),
the following response time results:
T
T
+T
R
PLC cycle
proc.
OS
OS
User program
after
before
L PW
user
user
prog.
prog.
Figure 10-2. Response Time in the Case of Direct Access without OB 2/OB 13
Explanation of Figure 10-2
If input signal
changes after the relevant direct access , the change will be recognized in the
next PLC cycle after reading in the signal with direct access . The user program scans the input
signal and responds by directly accessing the output module .
EWA 4NEB 811 6148-02
Input
signal
User program
OS
after
A I 1.0
user
prog.
T PLC cycle
Input signal
OS
after
T PW
user
prog.
T proc.
Rules Governing the Use of the S5-115F
Read input signal in
OS
before
S Q 4.0
user
prog
Read input
signal in
OS
User program
before
L PW
T PW
user
prog.
T proc.
Output response
OS
OS
after
before
user
user
prog.
prog.
Output
response
OS
OS
after
before
user
user
prog.
prog.
10-3
t
t
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