Rockwell Automation DeviceNet Media Design Installation Guide - Manual (Page 89)

Publication DNET-UM072C-EN-P - July 2004
Determine Power Requirements 4-11
One power supply (end-connected)
The following example uses the look-up method to determine the
configuration for one end-connected power supply. One end-connected power
supply provides as much as 8A near the power supply.
1. Determine the total length of the network.
106m
2. Add each device’s current together to find the total current.
0.10 + 0.15 + 0.30 + 0.10
3. Find the value next largest to the network length using Figure 4.1 on
Page 4-4 to determine the approximate maximum current allowed for
the system.
120m (2.47A)= 0.65A
power
supply
TR TR PT T T T
D1 D2 D3 D4
0.10A 0.15A 0.30A 0.10A
23m
(75 ft)
30m
(100 ft)
53m
(175 ft)
106m
(350 ft)
T
TR = terminating resistorT = T-Port tap
PT = PowerTap tapD = device
41833
IMPORTANT
Make sure that the required power is less than the rating of
the power supply. You may need to derate the supply if it is
in an enclosure.