The CompactLogix System

Learn Logix Part 2.5. This article gives an overview of the CompactLogix system and introduces the components that make up the CompactLogix system such as the bus connectors, power supply, and controllers.

Learn Logix is a series of articles designed to teach you everything you need to know to work with Rockwell Automation’s Studio 5000 Logix Designer and the Logix 5000 series of PLCs.

In the last part of the series, we learned about the ControlLogix communication modules and their features. In this part of the series, we’ll look at the CompactLogix system and the components that make up the system.

The CompactLogix system is a modular, single-controller automation system. In a CompactLogix system, you can have one controller, multiple I/O modules, and multiple communication modules in a bank.

A CompactLogix system only supports eight modules per bank but can be expanded to include up to three banks.

Each bank can be mounted on a DIN rail or in panels both horizontally and vertically.

There are some limitations to where modules can be positioned in the bank. For example, only four modules are allowed to the left and to the right of the power supply and the controller must be mounted on the left of the power supply. Tools like Rockwell Automation’s Integrated Architecture Builder (IAB) can help you to understand and plan around these limitations.

Sliding Bus Connector

Unlike the ControlLogix system, the CompactLogix system does not use a physical chassis. Instead, it has a sliding bus connector that allows modules to communicate over the CompactBus backplane.

When a module is placed on the bank, the sliding bus connector is used to establish a connection between the new module and the existing modules on the bank.

Power Supply

The power supply used in a CompactLogix system depends on the series of CompactLogix controller being used.

Older 1769-L3X controllers use the 1769-PA2 power supply shown in the image above.

Newer 5069 CompactLogix 5380 controllers can use any power supply that meets the system requirements. The CompactLogix 5380 controller then provides power to the other devices in the bank through removable terminal blocks.

Just like with the ControlLogix system, field devices in a CompactLogix system require a separate power supply.


In this article, we learned about the CompactLogix system and the main components that make up the system.

In the next part of the series, we will learn about the I/O modules that are available for the CompactLogix system. If you haven’t already, be sure to subscribe to the mailing list below to be notified when the next part is available.

Update: You can find the next part of the Learn Logix series, The CompactLogix Controllers, here. This article gives an overview of the 1769 and 5069 CompactLogix controllers, their features, and the differences between the two series of controllers.

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