Rockwell Automation 1769-L23E-QB1B_L23E-QBFC1B_L23-QBFC1B CompactLogix Packaged Controllers Quick Start and User Manual - Manual (Page 230)

230 Publication IASIMP-QS010B-EN-P - October 2009
Chapter 4 Add Additional Local I/O
Determine Expansion
Module Limits The maximum amount of expansion modules that can be used with the
packaged controllers is two, with the exception of the L23E-QB1B controller,
which can support three. Within that limit, the number of expansion I/O
modules that can be attached to the packaged controller depends on the bus
current draw of the modules being attached.
Each packaged controller has a specified amount of available bus current as
shown in this table.
To determine the number of expansion I/O modules you can add, total the
bus current draw (maximum) of your planned expansion I/O modules and the
end cap. If your result is less than the packaged controller’s maximum available
bus current, you are within the expansion I/O limit of your packaged
controller.
Example of Expansion I/O Calculation
In this example, these expansion I/O modules and bus current draws are
planned for use with the 1769-L23E-QBFC1B packaged controller.
The total bus current draw of the Compact I/O modules (310 mA at 5V DC,
or, 60 mA at 24V DC) is less than the total available bus current of the
packaged controller (450 mA at 5V DC, or, 600 mA at 24V DC). These
planned expansion I/O modules are within the limits of the
1769-L23E-QBFC1B packaged controller.
Packaged Controller Bus Current and Expansion Module Limits
Cat. No. Total Available 5V DC Bus
Current Total Available 24V DC Bus
Current
1769-L23E-QB1B 1 A (1000 mA) 710 mA
1769-L23E-QBFC1B 450 mA 550 mA
1769-L23-QBFC1B 800 mA 600 mA
Planned Expansion I/O
Module
5V DC Bus Current
Draw, max
(1)
(1) The maximum bus current draw specification for each Compact I/O module is available in the Compact I/O Selection
Guide, publication
1769-SG002 . This publication also provides further explanation of and a table for the calculation of
Compact I/O power supply requirements.
24V DC Bus Current
Draw, max
(1)
1769-OV16 Sink Output Module 200 mA 0 mA
1769-IF4 Analog Input Module 105 mA 60 mA
1769-ECR End Cap 5 mA 0 mA
Total Bus Current Draw 310 mA 60 mA