CompactLogix 1769-L31, L32E, L35E, L23E end of life — migration path to 5370/5380

Four discontinued catalog numbers — and a caveat about the "replacement"

According to the lifecycle page for each catalog number on rockwellautomation.com (read 25 September 2026):

The caveat is in the L31 row: Rockwell lists the L32E as its direct replacement, but the L32E was itself discontinued four years later. Buying an L32E to replace an L31 today means buying a catalog number that is already end-of-life. The right path is to move straight to a generation that is still sold. The equivalence table in the CompactLogix selection guide (1769-SG003A, 03/2022, p. 14) groups the L31 and L32E for replacement by the 1769-L30ER / L30ERM, and the L35E by the 1769-L33ER / L33ERM; if the serial port must be kept, Rockwell suggests CompactLogix 5380 with a 5069-SERIAL module. An L32E system with more than 8 expansion modules cannot use the L30ER (maximum 8) — it has to go to the L33ER, L33ERM or L36ERM.

Two generations currently sold: 5370 and 5380

• CompactLogix 5370 (1769-L3xER): reuses the existing 1769 I/O modules — this is the main reason to choose 5370 when the panel is full of 1769 I/O and rewiring is to be avoided. Examples: 1769-L33ER (2 MB, up to 16 1769 modules), 1769-L36ERM (3 MB, motion). Rockwell lists 5370 as Active Mature — still sold and supported, but a successor generation exists.
• CompactLogix 5380 (5069-L3xxER): the current generation, with 5069 Compact 5000 I/O — faster, 1 Gb Ethernet ports, but 1769 modules cannot be plugged in. Choose 5380 for a new panel, or when the 1769 I/O is also due for replacement. Examples: 5069-L320ER, 5069-L330ER (the exact catalog number depends on the configuration).

Quick selection rule: 1769 I/O still in good condition → 5370; new build or I/O also old → 5380. Do not choose on controller price alone; the real cost lies in wiring, terminals and days of downtime.

Case by case

1769-L31 (serial only). Programs are usually small, communicating over DF1/Modbus serial with an HMI or instruments. Moving to 5370/5380 is the first time the system has Ethernet — the HMI has to be planned for: an older serial-connected PanelView may need replacing or a converter added. Keeping serial requires a dedicated module/adapter, which should be checked before the approach is fixed.

1769-L32E / L35E. These already have Ethernet, so moving to the L33ER (or 5069-L320ER) is the most natural step; memory capacity increases, so the program does not have to be cut down. Rockwell lists the L35E as "Engineering Replacement" (no catalog number given) because, depending on the configuration, an L33ER or L36ERM may be needed — check the number of modules, tags, tasks and motion in use before fixing the catalog number.

1769-L23E-QB1B (packaged). The replacement 1769-L24ER-QB1B is also a packaged unit with embedded 16 DI / 16 DO and up to 4 1769 modules, so the wiring stays almost unchanged; note that the L24ER belongs to the 5370 family (Active Mature) and uses the 1784-SD1 memory card supplied with the unit.

Before converting the program — check 5 things

1. Is the original project file still available? Without the .ACD file the program has to be uploaded from a controller that still works; a failed controller means a lost program — which is why regular backups matter.
2. RSLogix 5000 / Studio 5000 version: 5370/5380 need a newer Studio 5000 version than the RSLogix 5000 typically used with the L3xE — check on PCDC, and include licensing.
3. Instructions and configuration that do not carry over: some instructions, legacy module properties and serial configuration must be fixed by hand when changing controller family; Studio 5000 reports errors when the controller type is changed — read the whole error list before going to site.
4. Which 1769 I/O modules are in use, and at which firmware: 5370 accepts 1769 I/O but still has limits on the number of modules and their distance from the power supply; with 5380 the I/O must be replaced.
5. Network devices and HMI: changing the controller is the time to check the switches as well (ordinary switch → managed Stratix) and the HMI (PanelView Plus 6 → Plus 7) if they fit in the same shutdown window.

Survey and convert the project beforehand, so that the shutdown window is left for the swap and the test run. Package scope: End-of-life module / CPU replacement.