Specifications

14
1768-SG001A-EN-P -- March 2006
CompactLogix Selection Guide
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Right end cap 1769-ECR
Left end cap 1769-ECL
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The final I/O bank in the CompactLogix system needs an end cap on the end without the
expansion cable.
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In addition to local I/O, the CompactLogix controller can control remote (distributed) I/O
via the:
y EtherNet/IP network using a 1768-ENBT communication module.
y DeviceNet network using a 1769-SDN scanner module.
While local I/O can be lower in cost and easier to configure, configuring distributed
I/O offers:
y More versatility in laying out your system
y More communication options, such as DeviceNet, ControlNet, and EtherNet/IP
networks
y Ability to configure the listen-only communication format for remote I/O modules
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The 1769 backplane is a master/slave backplane. All 1769 I/O modules in a CompactLogix
system are scanned asynchronous to the program scan at a configurable Requested
Packet Interval (RPI) rate. You configure an individual RPI for each local 1769 I/O module.
The controller continually scans the control logic. One scan is the time it takes the
controller to execute the logic once. Input data transfers to the controller and output data
transfers to output modules asynchronous to the logic scan.
Important: The CompactLogix 1769 and 1768 backplanes do not support Removal and
Insertion Under power (RIUP). While the CompactLogix system is under power, any break
in the connection between the 1768 power supply and the controller (such as removing
the power supply, controller, or 1768 module) clears controller memory (including the user
program). Any break between the 1768-L43 controller and 1769 I/O does not clear
memory but causes a major fault in the controller.