Rockwell Automation DeviceNet Media Design Installation Guide - Manual (Page 81)

Publication DNET-UM072C-EN-P - July 2004
Determine Power Requirements 4-3
Use the Look-up Method To determine if you have adequate power for the devices in your cable system,
see the following examples and figures. You have enough power if the total
load does not exceed the value shown by the curve or the table.
In a worst-case scenario, all of the nodes are together at the opposite end of
the power supply.
TIP
This method may underestimate the capacity of your
network by as much as 4 to 1. See the following section to
use the full-calculation method if your supply does not fit
under the curve.
41710
For this configuration example Flat cable
uses figure Thick
cable uses
figure Thin cable
uses figure
One power supply (end-connected) Figure 4.2 Figure 4.1 Figure 4.7
One power supply (middle-connected) Figure 4.2 Figure 4.1 Figure 4.7
NEC/CECode current boost configuration (V+
cut) Figure 4.2 Figure 4.1 Figure 4.7
Two power supplies (end-connected) Figure 4.6 Figure 4.5 *
Two power supplies (not end-connected) Figure 4.4 Figure 4.3 *
* You can draw as much as 3A from a thin cable trunk line if the power supply separation is
below 70m (230 ft).