5-19
Communications Processor CP 541
EWA 4NEB 812 6188-02
Calculation of the local cycle times:
Two receive messages and two send messages are present. The message
transit times are given by:
–
Sending of 20+4 bytes to Station 2: 24
2 ms + 44 ms = 92 ms
–
Sending of 20 bytes to Station 3: 20
2 ms + 44 ms = 84 ms
–
Receiving of 10+4 bytes from Station 2:
14
2 ms + 44 ms = 72 ms
–
Receiving of 8 bytes from Station 3: 8
2 ms + 44 ms = 60 ms
Messages sorted according to size:
–
Sending: 92 ms, 84 ms
–
Receiving: 72 ms, 60 ms
Verification of conditions for the send delay time:
POL
shortest send m shortest receive message
POL = 100 ms (defaultsetting in DB1)
84 ms + 60 ms = 144 ms
You obtain the local cycle time for sending by adding the individual values.
Sending
92 ms
84 ms
(92 + 84 + 72 + 60) ms
Receiving
72 ms
60 ms
(
)
= 308 ms
You obtain the local cycle time for receiving by adding the individual values.
Receiving
72 ms
60 ms
(72 + 60 + 92 + 84) ms
Sending
92 ms
84 ms
(
)
= 308 ms
Node 1
Local Cycle Time
for Sending STN 1
Local Cycle Time
for Receiving
STN 1
CP 541 with S5-95F/S5-115F