5. SETTINGS AND PROCEDURES BEFORE OPERATION
5
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7
MELSEC-A
5.6 Instructions for Connecting the Network Power Supply
This sections describes the instructions for connecting the network power supply.
5.6.1 Network power supply unit installation position
Follow the procedure below to determine the position to install the network power supply unit.
1) Calculate the current consumption of the stations required on the network.
2) Measure the total length of the network.
3) Refer to Tables 5.1 and 5.2 to determine the maximum current capacity corresponding to
the network length and type of cable used.
4) If the current value calculated at step 1) is less than the current value calculated at step
3), any of the network power supply unit installation positions described in Section 5.6.2
can be used.
5) If the current value calculated at step 1) exceeds the current value calculated at step 3),
refer to Section 5.6.2 to determine whether the network power supply unit can be installed
near the center of the network to supply power to all stations.
6) If the results from step 5) indicate that power cannot be supplied to all stations, increase
the number of network power supply units.
Table 5.1
Maximum Current Capacity Corresponding to
the Network Length of Thick Cable
Network length (m)
0
25
50
100
150
200
250
300
350
400
450
500
Maximum current (A)
8.00
8.00
5.42
2.93
2.01
1.53
1.23
1.03
0.89
0.78
0.69
0.63
Table 5.2
Maximum Current Capacity Corresponding to
the Network Length of Thin Cable
Network length (m)
0
10
20
30
40
50
60
70
80
90
100
Maximum current (A)
3.00
3.00
3.00
2.06
1.57
1.26
1.06
0.91
0.80
0.71
0.64
POINT
Use a network power supply unit with a current capacity exceeding the required total
current consumption.