Rockwell Automation DeviceNet Media Design Installation Guide - Manual (Page 95)

Publication DNET-UM072C-EN-P - July 2004
Determine Power Requirements 4-17
1. Determine the total length of the network.
274m
2. Add each device’s current together to find the total current.
0.25+0.50+0.10+0.25+1.00+0.10 = 2.20A
3. Find the value next largest to each section’s length using Figure 4.5 on
page 4-8 to determine the approximate maximum current allowed for
each section.
280m (3.96A)
Since the total current does not exceed the maximum current, the system will
operate properly (2.20A
≤ 3.96A).
power
supply power
supply
274m
(900 ft)
122m
(400 ft) 122m
(400 ft)
76m
(250 ft) 76m
(250 ft)
30m
(100 ft) 30m
(100 ft)
TR TR T T T T T T PT PT
D1 D2 D3 D4 D5 D6
0.25A 0.50A 0.10A 0.25A 1.00A 0.10A
TR = terminating resistorT = T-Port tap
PT = PowerTap D = device
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Results