Rockwell Automation DeviceNet Media Design Installation Guide - Manual (Page 97)

Publication DNET-UM072C-EN-P - July 2004
Determine Power Requirements 4-19
3. Find the value next largest to the length of section 3 using Figure 4.3 on
page 4-6 to determine the approximate maximum current allowed
(approximately).
140m (3.40A)
Since the total current does not exceed the maximum current, section 3 will
operate properly (1.55A
≤ 3.40A).
Loading is 46% (1.55/3.40).
4. Determine the trunk line length of the other end section (section 1).
76m
5. Add each device’s current together in section 1.
2.25A
6. Find the value next largest to the length of section 1 using Figure 4.1 on
page 4-4 to determine the approximate maximum current allowed.
80m (3.59A)
Since the total current does not exceed the maximum current, section 1 will
operate properly (2.25A
≤ 3.59A). Loading is 63% (2.25/3.59).
7. Determine the length of the middle section (section 2).
274m
8. Add each device’s current together in section 2.
1.50+2.00 = 3.50A
IMPORTANT
If the total current in the section exceeds the maximum
current, move the power supply closer to the end and
repeat steps 1-3 until the total current in the section is less
than the maximum allowable current.
IMPORTANT
If the total current in the section exceeds the maximum
current, move the power supply closer to the end and
repeat steps 4-6 until the total current in the section is less
than the maximum allowable current.
Results
Results