Confirmation method, Countermeasures – Yaskawa 260IF DeviceNet System User Manual
Page 78
7.1 Wiring Communications Power Supply
7-5
7
Confirmation Method
The following confirmation must be performed for each node connected in one direction
from the power supply. If nodes are connected to both sides of the power supply, always
check each direction separately. Also, be sure to refer to the appropriate graph. The relevant
graph differs depending on whether thick or thin cables are used for the trunk line.
1. Calculate the total current consumption (A) for all nodes connected in one direction
from the power supply.
2. Refer to the graph and determine the maximum current flowing to the cable (B), based
on the type of cable and the distance from the power supply to the end of the trunk line.
3. If the total current consumption (A) calculated in step 1 is less than the maximum cur-
rent (B) found in step 2, i.e., if A
≤ B, then the power supply specifications are met for
all nodes in that direction.
4. If nodes are located on both sides of the power supply, repeat the confirmation process
using steps 1 to 3 for the nodes in the other direction.
Countermeasures
Consider the following countermeasures if the total current consumption (A) calculated in
step 1 is greater than the maximum current (B) found from the graph in step 2, i.e., if A
> B.
• Change the configuration so that the power supply is positioned in the middle of the net-
work and nodes are located on both sides of the power supply.
• If the nodes are already on both sides of the power supply, move the power supply
towards the nodes with the greater power supply requirements.
• If thin cables are being used, replace with thick cables.
If A
> B even after all of these countermeasures have been tried, verify using the formula,
using the actual node positions.
Example 1: Power Supply Positioned at One End of the Network
The following diagram shows the layout when the power supply is positioned at one end of
the network and a thick cable with a total length of 200 m is used.
0
0
1
2
3
10
20
30
40
50
60
70
80
90
100
(
Distance (m)
Max. current (A)