The Allen-Bradley PLC-5 (1785-L series) is a discontinued large PLC platform. Rockwell's migration path is ControlLogix (1756), with conversion tools from RSLogix 5 to Studio 5000 and options to keep DH+ and 1771 I/O during a phased cutover. For plants holding PLC-5 lines, Edmundson Industrial sources new-surplus, used-tested, and reconditioned PLC-5 processors, 1771 I/O, and chassis.
| Brand | Allen-Bradley / Rockwell Automation |
| Family | PLC-5 (1785 series) |
| Common catalog numbers | 1785-L11B, L20B, L40B, L60B, L80B · 1785-L40E / L80E (Ethernet) · 1771 I/O |
| Lifecycle | Discontinued / end-of-life — verify current Rockwell status at quote |
| Programming | RSLogix 5 (legacy) |
| If you have (obsolete) | Recommended path | Notes |
|---|---|---|
| PLC-5 processor (1785-L…) | ControlLogix 1756-L8 | Convert RSLogix 5 to Studio 5000; plan the I/O strategy and checkout time. |
| PLC-5 on a DH+ network | ControlLogix with DH+ bridge (1756-DHRIO) | Keep DH+ / RIO devices during a phased migration. |
| 1771 I/O | Reuse on migration, or like-for-like surplus | 1771 reuse paths exist; confirm module support when planning. |
| Keep the program — no re-engineering | New-surplus / used-tested PLC-5 (we source) | Fastest path. Match processor memory, comms, and series/revision. |
Cross-references are starting points — confirm processor memory, communications, and program compatibility before substituting. We'll verify on request.
No. ControlLogix is the successor platform. PLC-5 still runs major process, utility, and heavy-industry systems, so spares — processor, 1771 I/O, memory battery — buy time to migrate on a planned schedule rather than during an outage. We source the originals and quote the ControlLogix path.
Condition always disclosed before sale — new-surplus, used-tested, or reconditioned — with photos on request.
or send catalog numbers to sales@edmundsonindustrial.com · (832) 975-8827 · Houston, TX. Same-day response on most requests.
Condition disclosed before sale. Same-day response on most requests.