Siemens SIMATIC CP 541 Manual page 57

Node 3
Local Cycle Time
for Sending STN 3
Local Cycle Time
for Receiving
STN 3
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 message + 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
Receiving 84 ms
*
Receive message is filled in.
You obtain the local cycle time for receiving by adding the individual values.
Receiving 84 ms
Sending 68 ms
*
Send message is deleted.
CP 541 with S5-95F/S5-1 15F
60 ms
( (68 + 60 + 84 + 84) ms
*
84 ms
= 296 ms
( (84 + 68) ms
*
60 ms
= 152 ms
)
)
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