Omron CS1W-CLK12-V1, Operation Manual

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200
Message Delay Times Section 9-4
Example
In this example, the maximum transmission delay is calculated for an instruc-
tion receiving 256 words of data in a system with 62 nodes. Network specifics
are detailed below:
H-PCF cable used
Connection method:
Ring connection
Transmission distance: 8 km
Transmission speed: 2 Mbps
Max. node address: 62
Number of nodes: 62
Number of polled nodes per comm cycle: 4
Local node execution: Synchronous
Remote node execution: Asynchronous
Number of words: 256
Data link: Inactive
Note This communications cycle time is calculated assuming that there is no node
that transmits event frames before the RECV command is sent.
Link Unit servicing (local node)
×
2 PLC cycle time (local node)
×
2
Link service processing (local node)
×
2 1 ms
×
2 = 2 ms
Transmission processing (command) 2 ms
Communications cycle
×
2 (see note) (1,740
×
4 + 450
×
62 + 1,100
×
0 + 4
×
0 + 2
×
7
×
8 + 3,000)
×
2 =
37,972
µ
s
×
2
≅
75.9 ms
Transmission delay (command) 0.112
≅
0.1 ms
Reception processing (command) 1.3 ms
Link servicing interval (remote node) As required by Programming Device
(remote node)
Link service processing (remote node) 1 ms
Transmission processing (response) 0.00075
×
256 + 2 = 2.192
≅
2.2 ms
Transmission delay (response) 0.008
×
256 + 0.112 = 2.16
≅
2.2 ms
Reception processing (response) 0.00075
×
256 + 2 = 2.192
≅
2.2 ms
Total (max. transmission delay) PLC cycle time (local node)
×
2 +
Peripheral servicing time (remote
node) + 88.9 ms