Manual

Installing the Assembly
Chapter 6
62
Avoiding Backplane Power Supply Overload
For each module you plan to install in the I/O chassis, add up it current
load on the backplane power supply. Be sure that this total current is not
so large as to overload the backplane power supply.
The backplane power supply current load of the servo positioning
assembly is:
1771M3
controller
1771ES
expanders
Total
Current
1 1 3.45A
1 2 5.15A
1 3 6.85A
Note that if you add the total current draw of one 1771-M3 controller,
three 1771-ES expanders, and either an I/O adapter or mini-processor
module, the total would exceed 8A. In that case you could not use a
1771-P1 or 1771-P2 power supply because they are rated at 6.5A.
If the total current exceeds 6.5A, you can use Power-Supply Modules (cat.
no. 1771-P3, -P4, -P5) to provide 8A, 11A or 16A. The following table
lists the number of axes you can control with a servo positioning system
in a 1771-A4 I/O chassis, based on power requirements and compatibility
of other components used with the 1771-A4 I/O chassis.
I/O Adapter or MiniProcessor Module Cat. No.
Power
Supply
Cat. No. 1771AL 1771AS 1772LS 1772LSP 1771LV
1771P1 1 Axis
1771P2 2 Axes 2 Axes
1771P3 2 Axes 1 Axis
1771P4 3 Axes 3 Axes 3 Axes
1771P4 plus
1771P3 or
a second
1771P4 3 Axes 3 Axes