Allen-Bradley SLC 500: Replacement & Cross-Reference

The Allen-Bradley SLC 500 is a retired PLC platform. Rockwell Automation has discontinued the family and ended active production. The recommended migration path is CompactLogix (5370/5380 series), which Rockwell supports with dedicated SLC-to-CompactLogix conversion tools. If you need to keep an existing machine running without re-engineering, Edmundson Industrial sources new-surplus, used-tested, and reconditioned SLC 500 processors, 1746 I/O modules, racks, and power supplies.

Status

Brand	Allen-Bradley / Rockwell Automation
Family	SLC 500 (1746 / 1747 series)
Common catalog numbers	1747-L552, 1747-L551, 1747-L542, 1747-L532 (processors) · 1746-OW16, 1746-IA16, 1746-NI8, 1746-IB16 (I/O) · 1746-P2 (power supply) · 1746-A4/A7/A10/A13 (racks)
Lifecycle	Discontinued / end-of-life: verify current Rockwell status at quote
Programming	RSLogix 500 (legacy)

Cross-Reference

If you have (obsolete)	Recommended path	Notes
SLC 5/05 (1747-L551 / L552)	CompactLogix 5380 (5069-L306ER class)	Rockwell migration path. Reprogram in Studio 5000; conversion tools assist, but plan I/O remapping and checkout time.
SLC 5/03 – 5/04 (1747-L532 / L542)	CompactLogix 5370 / 5380	Same path. Communications change from DH-485 / DH+ to EtherNet/IP: confirm what else on the network talks to the SLC before migrating.
Any SLC: keep program running	New-surplus / used-tested SLC 500 (we source)	Keeps the installed program with no re-engineering. Match processor series and verify OS / firmware revision against your program.
1746 I/O modules	Like-for-like 1746 surplus, or 5069 Compact I/O on migration	I/O wiring conversion systems exist for migrations: ask when planning.
1746 racks / power supplies	Like-for-like surplus	Shelf spares for P2 power supplies are cheap downtime insurance.

Cross-references are starting points: confirm processor series, rack slot count, I/O mix, and program compatibility before substituting. Send your catalog numbers and we'll verify the match.

Key Specs (platform overview)

Modular chassis-based PLC: 4-, 7-, 10-, and 13-slot racks (1746-A4 through A13)
Processor range: SLC 5/01 through 5/05; 5/05 adds embedded Ethernet
Communications by model: DH-485, DH+, RS-232, Ethernet (5/05)
Wide 1746 discrete and analog I/O family; confirm module class and terminal wiring per slot
Programmed in RSLogix 500: programs do not transfer directly to Studio 5000 without conversion

Is the SLC 500 still made?

No. Rockwell retired the SLC 500 platform and active support has ended. Plants running SLC-based machines have two practical options: migrate to CompactLogix on a planned schedule, or keep critical spares, processor, power supply, key I/O, on the shelf from the surplus market. Most maintenance teams do both: spares buy time to migrate on your schedule instead of during an outage.

If a migration also means panel changes, Edmundson Industrial's fabrication side can supply custom sub-panels, adapter plates, and modified enclosures so the new hardware lands cleanly in the old footprint.

FAQ

Is the Allen-Bradley SLC 500 discontinued?

Yes: the SLC 500 family is discontinued. Parts remain available through surplus and used/reconditioned channels like Edmundson Industrial.

What replaces the SLC 500?

CompactLogix (5370/5380) is Rockwell's migration path. Programs must be converted from RSLogix 500 to Studio 5000, and I/O is remapped to 5069 Compact I/O.

Can I still buy SLC 500 processors and I/O?

Yes: new-surplus and used-tested units are available. We source 1747 processors, 1746 I/O, racks, and power supplies without requiring an immediate migration.

Should I migrate or buy spares?

If the machine runs and downtime is expensive, a shelf spare is the cheapest insurance. Migration makes sense at planned rebuilds or when your specific modules get scarce.

What do you need to quote SLC 500 parts?

Catalog numbers (or nameplate photos), acceptable condition, new-surplus, used-tested, or reconditioned, and your need-by date.

Availability & Quote

Edmundson Industrial sources SLC 500 components in new-surplus, used-tested, and reconditioned condition as available. Condition is disclosed before sale, with photos on request.

Request a Quote

or send catalog numbers to sales@edmundsonindustrial.com · (832) 975-8827 · Houston, TX. Response timing is confirmed with the request. Line down? Say so in the subject line.

Related Allen-Bradley legacy pages

Want a quick quote for Allen-Bradley SLC 500?

Fill out your contact info here, and we'll get a quote sent to you ASAP!