Rockwell Automation 1769-PB4 Compact I/O Expansion Power Supplies - Manuel (Page 14)

14 Compact I/O Expansion Power Supplies
Publication 1769-IN028B-EN-P - October 2008
Verify Your System Power
Your system power budget is a consideration when using 1769 power supplies. This
determines the power that is being provided to the I/O modules. Refer to Calculate System
Power Requirements in the Compact I/O Selection Guide, publication
1769-SG002-EN-P,
for the power budget calculation worksheet.
1. After you have reviewed the amount of current consumed by your system, verify that
your power supply has adequate capacity for its bank of I/O modules.
See page 25 for graphs.
2. To do so, compare the current graphs to your totals for the following:
• total 5V DC
• total 24V DC
• total 24V DC sensor power (1769-PA2 only)
3. If your power supply load is at or above the limits of the allowable ranges shown in
the graphs, you must add an additional I/O bank.
See Connect the Power Supplies for additional information.
TIP
The total number of I/O modules cannot exceed 16 on a single bank with a maximum of 8
I/O modules on either side of the power supply.
When configuring your system using a MicroLogix 1500 controller, only one expansion
cable, one expansion power supply and a total of eight I/O modules may be used in a
maximum of two banks of I/O modules. The expansion power supply cannot be directly
connected to the MicroLogix 1500 controller.
IMPORTANT
An additional I/O bank must include its own power supply.
An end cap/terminator (1769-ECR or 1769-ECL) must also be used if the I/O bank is the
last in the system.