5-21
Communications Processor CP 541
EWA 4NEB 812 6188-02
Calculation of local cycle times:
Two receive messages and one send message are present. The message
transit times are given by:
–
Sending of 8 bytes to Station 1: 8
2 ms + 44 ms = 60 ms
–
Sending of 12 bytes to Station 2: 12
2 ms + 44 ms = 68 ms
–
Receiving of 20 bytes from Station 1:
20
2 ms + 44 ms = 84 ms
Messages sorted according to size:
–
Sending: 68 ms, 60 ms
–
Receiving: 84 ms
Verification of conditions for the send delay time:
POL
shortest send m shortest receive message
POL = 100 ms (default setting in DB1)
60 ms + 84 ms = 144 ms
You obtain the local cycle time for sending by adding the individual values.
Sending
68 ms
60 ms
(68 + 60 + 84 + 84) ms
Receiving
84 ms
84 ms
*
(
)
= 296 ms
*
Receive message is filled in.
You obtain the local cycle time for receiving by adding the individual values.
Receiving
84 ms
(84 + 68) ms
Sending
68 ms
60 ms
*
(
)
= 152 ms
*
Send message is deleted.
Node 3
Local Cycle Time
for Sending STN 3
Local Cycle Time
for Receiving
STN 3
CP 541 with S5-95F/S5-115F