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CP 541 with S5-95F/S5-1 15F
5.3.6
Example of Verification of Safety Times
Example
Local Cycle Time
Safety Time
STN
1
First formula from Page 5-14:
SINEC L1 safety time for receiving >=
(S5-115F)
2 t
LUS,STN2
2 164 ms + 2 308 ms + 100 ms = 1044 ms
2000 ms >= 1044 ms
Condition is fulfilled.
2
First formula from Page 5-14:
SINEC L1 safety time for receiving >=
(S5-95F)
2 t
LUS,STN1
2 308 ms + 2 304 ms + 100 ms = 1324 ms
2000 ms >= 1324 ms
Condition is fulfilled.
Safety time for sending =
2 t
LUS,STN2
5-22
The example previously described (see Section 5.3.5) serves for verifying the
safety times.
We will now determine the safety time for a connection between the two pro-
grammable controllers, Stations 1 and 2.
By agreement with the inspector, a SINEC L1 safety time for receiving of 2 s
is specified.
You have determined the local cycle times from the example. They are as
follows:
Local Cycle Time for
Sending (t
)
LUS
2 sending (2 t
)
LUS
Receiving (t
)
LUE
2 receiving (2 t
)
LUE
From these data and taking into account the formula in Section 5.3.3 and the
data in 5.3.4, we obtain the safety times as follows:
Calculation
+ 2 t
+ t
=
LUE,STN1
L2
+ 2 t
+ t
=
LUE,STN2
L2
= 2 164 ms = 328 ms
STN 1
STN 2
308 ms
164 ms
616 ms
328 ms
308 ms
304 ms
616 ms
608 ms
Value to be Set
Second formula from Page 5-14:
2000 ms – t
=
LUE,STN1
2000 ms – 308 ms = 1692 ms
Safety time to be set with COM 115 F =
1690 ms
Second formula from Page 5-14:
2000 ms – t
=
LUE,STN2
2000 ms – 304 ms = 1696 ms
Safety time for receiving to be set with
COM 95F = 1600 ms
Safety time for sending to be set with
COM 95F = 400 ms
Communications Processor CP 541
EWA 4NEB 812 6188-02
STN 3
296 ms
592 ms
152 ms
304 ms
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