S5-115F Manual
Rules Governing the Use of the S5-115F
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
R
2 * T
PLC cycle
Figure 10-1.
Response Time in the Case of Cyclic Read-In of Process Signals
A I 1.0
t
Output response
Read input signal in
Input
signal
OS
before
user
prog.
OS
before
user
prog
OS
before
user
prog.
OS
after
user
prog.
OS
after
user
prog.
OS
after
user
prog.
TPLC cycle
User program
S Q 4.0
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
R
T
PLC cycle
+T
proc.
Figure 10-2. Response Time in the Case of Direct Access without OB 2/OB 13
Tproc.
User program
T PW
User program
L PW
L PW
Read input
signal in
Output
response
t
Input signal
OS
before
user
prog.
OS
before
user
prog.
OS
before
user
prog.
OS
after
user
prog.
OS
after
user
prog.
OS
after
user
prog.
T PW
Tproc.
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
10-3
