Yaskawa 260IF DeviceNet System - Manual (Page 76)

7.1 Wiring Communications Power Supply
7-3
7
Nodes on One Side of the Power Supply
7.1.3 Methods for Deciding the Power Supply Positioning
Values to be Calculated
The power supply capacity required by each node and the voltage drop depending on the
length of the cable will determine whether or not the correct current can be supplied to each
node.
Calculate the following values.
• The current capacity required for each node.
• The distance from the power supply.
Power Supply Calculation Method
There are two methods for calculating the power supply for the trunk line.
Simple Calculation from the Graph
The simple calculation from the graph is based on the worst configuration, with maximum
voltage drop, as shown in the following diagram. The network will operate normally, there-
fore, if the conditions are met for a calculation from the graph.
Calculation from the Formula
The voltage drop is calculated from the transmission cable resistance and current consump-
tion.
The conditions may be met through the results of calculation from the fomula even if the
power supply specifications are not met through simple calculation from the graph. The net-
work will operate normally if conditions are met for either the calculation from the formula
Power Supply Tap
or T-branch Adapter
Communications
power supply
Node Node Node Node
Node
Node
Node
Node
Communications power
supply