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131
Communications Cycle Time
Section 8-2
In this example, B to E in the equation have the following values.
B: 4
C: 8
D: 2
E: 4,024
The communications cycle time is thus as follows:
600
×
4 + 110
×
8 + 320
×
2 + 4
×
4,024 + 2,290 = 22,306 (
μ
s)
≅
22 (ms)
Calculation Example for
Optical Ring Networks
with H-PCF Cable
Communications conditions are as follows:
Type:
Optical Ring
Transmission medium:
H-PCF cable
Transmission distance:
8 km
Baud rate:
2 Mbps (fixed)
Network parameters:
Defaults
Max node address:
62
Polled nodes per comm cycle: 4
Event-frames per comm cycle: 35
Network configuration:
8 nodes
Nodes that send messages: 2
nodes
Bytes in all messages sent:
2,012
×
2 bytes
In this example, B to F in the equation have the following values.
B: 4
C: 8
D: 2
E: 4,024
F: 7
×
8
The communications cycle time for Token Ring Mode is thus as follows:
1,740
×
4 + 450
×
8 + 1,100
×
2 + 4
×
4,024 + 2
×
7
×
8 + 3,000 = 31,968 (
μ
s)
≅
32 (ms)
The communications cycle time for Token Bus Mode is thus as follows:
1,300
×
4 + 110
×
8 + 320
×
2 + 4
×
4,024 + 2
×
7
×
8 + 1,800 = 24,728 (
μ
s)
≅
25 (ms)
8-2-3
Maximum Delay for Line Disconnections in Token Ring Mode
Although the duplicated transmission lines used in Token Ring Mode for Opti-
cal Ring Networks will ensure that communications continue even if the trans-
mission line is broken in one location, the communications cycle time will be
affected.
The data that is received first from the SL1 or SL2 reception interfaces is actu-
ally used, but the data that would normally be received first may be lost. The
difference in time to receive the same data on SL1 and SL2 is thus the delay
that can occur for line disconnections.
This delay results as the token is passed between nodes. The delay for the
entire network will thus be the total of all the delays between each node pair,
and the total delay time will increase the communications cycle time.
Summary of Contents for SYSMAC 3G8F7-CLK12-EV1
Page 2: ......
Page 4: ...iv ...
Page 20: ...xx Conformance to EC Directives 6 ...
Page 48: ...28 Applications Precautions Section 1 4 Example CX Programmer Response Timeout Setting ...
Page 68: ...48 Backup Power Supply Wiring Optical Ring Systems Only Section 2 4 ...
Page 74: ...54 Using the C Library Section 3 2 ...
Page 110: ...90 Changing the Data Link Tables with Active Data Links Section 5 5 ...
Page 187: ......