
1.CONNECTING DeviceNet FUNCTIONS CONNECTION B-63404EN/03
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Total current consumption = 0.1A + 0.15A + 0.05A + 0.25A = 0.65A
Maximum possible current calculated from the table for thick cable =
1.53A
The relationship becomes "total current consumption is less than the
maximum current," so you can verify that power can be supplied to all
nodes.
When the power supply unit is located at the center (example 2):
The following shows an example where thick cable having a total
length of 240 m is used for the power supply, and the communications
power supply is located at the center of the network.
As the communications power supply is located in the center of the
network, the maximum current flows to both the left and right of the
power supply. For this reason, a current twice the maximum current
can be supplied compared with when the communications power
supply is located at the end of the network.
In this example, the current consumptions of each node are assumed
to be as shown in the following figure.
Total length of power supply line (left side) = Total length of power
supply line (right side) = 120 m
Total current consumption (left side) = 0.1 A + 0.45 A = 0.55 A
Total current consumption (right side) = 0.25 A + 0.3A = 0.55 A
Maximum current (left side) calculated from the table for thick cable
= Approx. 2.5 A
Maximum current (right side) calculated from the table for thick cable
= Approx. 2.5 A
(The above values are calculated by linear approximation between
100 and 150 m.)
The relationship becomes "total current consumption (left side) is less
than the maximum current (left side)" and the "total current
consumption (right side) is greater than the maximum current (right
side)," so you can verify that power can be supplied to all nodes.
Terminator
Node Node
Terminator
Power supply tap
NodeNode
120m
Trunk line (5-lead cable)
0.3A0.25A0.45A0.1A
120m
Within
3 m
Communications
power supply