Rockwell lists the SLC 5/04 1747-L542 and the SLC 5/05 1747-L552 and 1747-L553 as discontinued on 31 March 2024. Each precise 1747 catalogue number should be checked individually; this is not a universal lifecycle date for every 1746/1747 module.
Confirmed lifecycle milestones
| Date | Manufacturer milestone |
|---|---|
| 31 March 2024 | SLC 5/04 1747-L542 marked discontinued |
| 31 March 2024 | SLC 5/05 1747-L552 marked discontinued |
| 31 March 2024 | SLC 5/05 1747-L553 marked discontinued |
| After discontinuation | Repair or exchange may remain available — verify with Rockwell |
Dates and scope are manufacturer-led; check individual catalogue numbers, market-specific rules and any updates before placing orders.
Which SLC 500 processors were discontinued?
Rockwell's product records show 31 March 2024 discontinuation dates for the SLC 5/04 1747-L542 (32K memory), SLC 5/05 1747-L552 (32K memory) and SLC 5/05 1747-L553 (64K memory). These product pages classify the units as discontinued, with an engineering replacement category. Other SLC 500 CPUs, modules and series have their own product lifecycle records.
When sourcing a spare, record the whole number, the processor series, firmware and memory requirements. An apparently similar processor may have different communications, capacity or programme implications.
SLC 5/04 versus SLC 5/05: network consequences
The 5/04 and 5/05 are not simply identical controllers with different memory sizes. The SLC 5/04 commonly uses Data Highway Plus (DH+) and serial connections, while the SLC 5/05 adds Ethernet networking. Existing plant software, HMIs, drives and remote I/O can depend on those communications choices.
Do not order a processor on catalogue-family similarity alone. Check the backplane, rack arrangement, communication configuration, network addressing, processor revision and legacy peripherals before purchase or replacement.
What should maintenance teams keep with the spare?
Have a readable RSLogix 500 project, verified controller programme, data tables and configuration information. Retain licensing and a functioning engineering workstation or virtual-machine arrangement where needed. Also keep a note of programme access credentials and recovery steps in a secure approved location.
For obsolete SLC installations, a tested recovery method, documented IP or node addresses, working communication cables and a correctly specified I/O spare may be more useful than buying a random 1747 CPU simply because it is inexpensive.
Planning a move to CompactLogix or ControlLogix
Migration involves more than replacing a chassis. Assess 1746 I/O, scanner and network modules, DH+ and serial integrations, processor scan behaviour, HMI communications, drives, data types and any safety architecture. Moving from RSLogix 500 to Studio 5000 usually requires design and testing rather than a direct file conversion.
Some factories choose to keep a known-good SLC spare while they stage the replacement. Others prioritise a full upgrade when downtime risk and scarce hardware outweigh the engineering cost. Both options start with an accurate equipment list.
Questions engineers ask
Is 1747-L552 still sold new by Rockwell?
Rockwell lists the 1747-L552 SLC 5/05 processor as discontinued as of 31 March 2024. Surplus or refurbished stock may exist through third-party suppliers.
Can SLC 500 modules still be repaired?
Some Rockwell discontinued product records still refer to repair services. Check the exact catalogue and series with Rockwell or an authorised repair provider before relying on availability.
Can I replace an SLC 5/04 with an SLC 5/05?
Not as a universal plug-and-play substitution. Communications and application requirements differ; review the exact hardware and software configuration.
Official manufacturer references
These are manufacturer product records and notices, not secondary resale listings. Check each source for more recent revisions.
Editorial review: 8 October 2026 · Prepared by Automation Outlet, an independent UK controls-engineering business. This article provides lifecycle information, not a guarantee of stock or technical interchangeability.