Comparing CompactLogix and ControlLogix Processors

Today, we’re going to take a look at Allen-Bradley’s popular CompactLogix and ControlLogix processor lines.

The ControlLogix and CompactLogix are Allen-Bradley’s most popular lines of Automation controllers. The ControlLogix is designed for larger, more demanding systems, requiring higher I/O counts. The CompactLogix, with its smaller, more affordable frame, is better suited to smaller applications. Here, we will examine the differences in detail.

  • The CompactLogix

The CompactLogix line sports two variants – modular chassis-free system and all-in-one controller with a chassis. The most popular all-in-one controllers are CompactLogix L23, L1XER, and L2XER. If you’ve used CompactLogix processors, you might have heard of these, as they were best-selling processors in the line. For the modular systems, the L30ER, L33ER, L32X, and L35X are the best-selling components.

The packaged CompactLogix processors are ready for work out-of-the-box, which is their main advantage. Conversely, the modular L3 models require a separated power supply, as well as a dedicated End Cap and are often paired with the local I/O system.

The CompactLogix processors similar to L1, L2, and L3 generations are branded as 5380 in today’s standards. The main characteristics of the 5380 CompactLogix processors are:

  • Slot for SD card, for use as a non-volatile memory
  • Embedded USB port
  • Industrial SD card with 1GB of memory included
  • Comes with an embedded super cap – battery not needed.
  • The ControlLogix

The ControlLogix series was the original Logix platform. It was first released 20 years ago, in 1999. The ControlLogix controllers are modular and consist of a power supply, processor, chassis, communication modules and/or I/O modules. It’s an advanced Controller that is used for more complex and bigger systems, and as such, it’s more expensive than a CompactLogix controller.

While the power supplies and chassis haven’t changed a lot from 1999, processors and communication modules changed as the new generation of processors emerged. Back in 1999, the first model was 1756-L1, which was then followed by the L55, better known as 5555. This controller had expandable memory instead of a built-in memory module, and the base unit came with no memory by default which meant that users needed to order a specific amount of memory before purchase.

The newer L6x was the first controller to come with non-volatile CompactFlash memory. This memory functioned similarly to EEPROM on older computers, which means that it could be erased and reprogrammed. The L7 came with a few improvements, such as an SD card slot, as well as the supercapacitor charging module.

Finally, Rockwell’s newest addition is the L8x, better known as 5580 ControlLogix line of processors. The major difference is in the performance, which is 20 times faster in program scans. It also has a 1GB Ethernet port, which improves communication capabilities and speed.

  • CompactLogix vs ControlLogix Comparison Table


Characteristics ControlLogix 5580 ControlLogix 5570 CompactLogix 5380 CompactLogix 5370 L3
Controller Tasks: 32/1000 programs/task 32/1000 programs/task 32/ 1000 programs/task 32/1000 programs/task
User Memory: 3 MB ( 1756-L81E) to 20 MB + 6 MB safety ( 1756-L84ES) 2 MB ( 1756-L71, 1756-L71EROM) to 8 MB + 4 MB safety ( 1756-L73S, 1756-L73EROMS) 0.6 MB ( 5069-L306ER, 5069-L306ERM) to 10 MB + 5 MB safety ( 5069-L3100ERS2, 5069-L3100ERMS2) 1 MB (11769-L30ER, 1769-L30ER-NSE, 1769-L30ERM, 1769-L30ERMK) to 5 MB + 1.5 MB safety ( 1769-L38ERMS, 1769-L38ERMSK, 1769-L38ERMOS)
Built-in Ports: Single-port Ethernet port, 10 Mbps/100 Mbps/1 Gbps, 1-port USB client 1 Port USB client, Dual-port Ethernet/IP 10 Mbps/100 Mbps 2 Ethernet ports, 10 Mbps/100 Mbps/1 Gbps, 1-Port USB client Dual-port Ethernet/IP 10 Mbps/100Mbps, 1-port USB client
Communication Options: EtherNet/IP, ControlNet™, DeviceNet™, Data Highway Plus™, Remote I/O, SynchLink™,USB Client EtherNet/IP, ControlNet™, DeviceNet™, Data Highway Plus™, Remote I/O, SynchLink™,USB Client EtherNet/IP,

USB Client


Embedded Switch, Single IP Address,


USB Client

Controller Connections: Not Applicable 500 Connections Not Applicable 256 Connections


Taking a look at the table, we can see that ControlLogix 5580 and 5570 are quite different, even though there’s a gap of only one generation. First, we have a difference in controller connections. ControlLogix 5570 is applicable to 500 connections, whereas 5580 doesn’t support any connection. As it’s a previous generation controller, ControlLogix 5570 sports Ethernet/IP port with a speed of 100 Mbps maximum. 5580, on the other hand, is able to go up to 1 Gbps, which is a huge improvement in terms of speed and reliability.

On the memory side, we have maximum 20 MB + 6 MB safety in 5580 and 5570 lags behind, with the maximum memory of 8 MB + 4 MB safety.

Turning to the CompactLogix; once again, the difference between generations is quite significant. The newer 5380 comes with 1 Gbps Ethernet port and the maximum memory capacity is 10 MB + 5 MB safety, whereas the 5370, has 5 MB + 1.5 MB safety. Allen Bradley made a significant improvement over the previous generation.

For more information or to purchase the CompactLogix series, click here!

For more information or to purchase the ControlLogix series, click here!


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