Mitsubishi Electronics QJ71DN91 ユーザーズマニュアル
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MELSEC-Q
4 SETUP AND PROCEDURES BEFORE OPERATION
(4) Mixed trunk line and drop line
The current capacity is calculated as shown below when the network power
supply unit is connected to a network with 200 m of thick-cable trunk line and 6 m
of thin-cable drop line.
supply unit is connected to a network with 200 m of thick-cable trunk line and 6 m
of thin-cable drop line.
Master station
1.0A
Termination
resistance
resistance
Network power
supply unit
supply unit
Slave station
0.15A
Slave station
0.05A
Slave station
0.25A
200m
Slave station
0.1A
Termination
resistance
resistance
Thick-cable power supply distance = 200 m
Drop line power supply distance = 6 m
Total current capacity = 0.5 A + 0.15 A + 0.05 A + 0.25 A + 0.1 A = 1.05 A
Max. current capacity of 200 m of thick cable (from Table 4.4) = 1.53 A
Max. current capacity of 6 m of drop line (from Table 4.6) = 0.75 A
Total current of devices connected to drop line = 0.1 A
Therefore, this configuration allows power supply to all nodes.
Table 4.6 Maximum current capacity corresponding
to the drop line length
Drop line length (m)
0.30
0.90
1.50
2.25
3.00
4.50
6.00
Max. current (A)
3.00
3.00
3.00
2.00
1.50
1.00
0.75