Allen-Bradley 1747-L551 SLC 5/05 16K Controller | Replacement, Equivalent & Selection Guide
The Allen-Bradley 1747-L551 is a SLC 5/05 series programmable logic controller (PLC) featuring 16K words of user memory and an integrated Ethernet/IP communication port. Designed for mid-range industrial automation, it delivers reliable performance in discrete, process, and motion control applications. This page serves as a comprehensive selection and replacement reference for engineers, procurement teams, and MRO buyers.
Technical Specifications
| Parameter | Specification |
|---|---|
| Catalog Number | 1747-L551 |
| Series | SLC 5/05 |
| User Memory | 16K Words |
| Communication Port | Ethernet/IP (10/100 Mbps) |
| Serial Port | RS-232 (Channel 0) |
| I/O Capacity | Up to 4096 I/O points |
| Scan Time | ~1 ms/K typical |
| Power Supply | Requires 1746-P series power supply |
| Chassis Compatibility | 1746 SLC 500 chassis |
| Operating Temperature | 0°C to 60°C (32°F to 140°F) |
| Storage Temperature | -40°C to 85°C |
| Relative Humidity | 5% to 95% (non-condensing) |
| Programming Software | RSLogix 500 / Studio 5000 Logix Designer (offline) |
| Certifications | UL, CE, CSA |
| Dimensions (H×W×D) | Slot-based (1746 chassis) |
| Weight | Approx. 400 g |
Compatible Replacement & Equivalent Models
When the 1747-L551 is unavailable or end-of-life, the following models are commonly evaluated as replacements. Always verify firmware, I/O mapping, and program compatibility before substitution.
| Model | Memory | Communication | Notes |
|---|---|---|---|
| 1747-L552 | 32K Words | Ethernet/IP | Direct upgrade; same SLC 5/05 platform, larger memory |
| 1747-L553 | 64K Words | Ethernet/IP | High-memory variant; program-compatible |
| 1747-L541 | 16K Words | DH+ / RS-232 | SLC 5/04 equivalent; no Ethernet — verify network requirements |
| 1747-L531 | 16K Words | RS-232 only | SLC 5/03; lower-cost alternative for non-networked applications |
| 1769-L30ER (CompactLogix) | 1 MB | Ethernet/IP | Modern migration path; requires program conversion to Ladder/FBD in Studio 5000 |
| 1769-L33ER (CompactLogix) | 2 MB | Dual Ethernet/IP | Recommended migration for new projects; full EtherNet/IP Device Level Ring support |
Note: SLC 500 to CompactLogix migration requires use of Rockwell’s Migration Tool and program re-validation. Contact Konmask for migration support.
Why Choose the Original Model
- Proven reliability — SLC 5/05 platform has decades of field-proven performance in harsh industrial environments.
- Drop-in compatibility — Fits existing 1746 chassis without hardware redesign, minimizing downtime during replacement.
- Ethernet/IP native — Integrated 10/100 Mbps port enables seamless integration with SCADA, HMI, and plant-floor networks.
- RSLogix 500 ecosystem — Extensive library of existing programs, function blocks, and add-on instructions available.
- Lower migration risk — Retaining the original platform avoids costly re-engineering, re-validation, and operator retraining.
- Spare parts availability — Konmask maintains stock of 1747-L551 and related SLC 500 components for rapid MRO fulfillment.
Typical Applications
- Discrete manufacturing: assembly lines, conveyor control, packaging machinery
- Process control: water treatment, chemical dosing, HVAC automation
- Material handling: palletizers, sorters, automated storage and retrieval systems (ASRS)
- Oil & gas: wellhead control, pipeline monitoring, pump station automation
- Food & beverage: batch processing, filling lines, CIP (clean-in-place) systems
- Building automation: energy management, access control integration
System Compatibility
- Chassis: 1746-A4, 1746-A7, 1746-A10, 1746-A13 (4, 7, 10, 13-slot)
- Power Supplies: 1746-P1, 1746-P2, 1746-P3, 1746-P4, 1746-P5, 1746-P6
- I/O Modules: Full 1746 I/O family — digital, analog, specialty, and motion modules
- HMI: PanelView 300–1400 series via DH-485 or Ethernet/IP
- SCADA: FactoryTalk View, Wonderware, Ignition (via EtherNet/IP driver)
- Programming: RSLogix 500 v8.x and above; offline compatible with Studio 5000
- Networks: EtherNet/IP, DH-485 (via 1747-AIC), DeviceNet (via 1747-SDN scanner)
Selection Guide
Use the following criteria to determine whether the 1747-L551 is the right choice — or which alternative best fits your application:
| Requirement | Recommended Model |
|---|---|
| Existing SLC 500 system, need Ethernet/IP, ≤16K program | 1747-L551 ✓ Best fit |
| Existing SLC 500 system, program >16K words | 1747-L552 or 1747-L553 |
| Existing SLC 500 system, DH+ network required | 1747-L541 (SLC 5/04) |
| New project, modern architecture preferred | 1769-L30ER or 1769-L33ER (CompactLogix) |
| Budget-constrained, no network required | 1747-L531 (SLC 5/03) |
| Safety application required | GuardLogix 5570 series (separate platform) |
Quality Assurance & Sourcing
- Authenticity: All units sourced from authorized distributors or verified surplus channels with full traceability documentation.
- Inspection: Each unit undergoes visual inspection, label verification, and functional power-on testing prior to shipment.
- Warranty: 12-month warranty against manufacturing defects; replacement or refund guaranteed.
- Condition options: New-in-box (NIB), factory-refurbished, and tested-surplus available — specify at time of inquiry.
- Documentation: Certificate of conformance, test report, and original datasheet provided upon request.
- Export compliance: ECCN classification and export documentation available for international orders.
How to Order
- Confirm catalog number: 1747-L551 (specify series revision if known, e.g., Series C)
- Specify required quantity and preferred condition (new / refurbished / surplus)
- Provide delivery timeline and destination country for lead time and shipping quote
- Submit inquiry via support@konmask.com or add to cart and proceed to checkout
- Receive proforma invoice within 1 business day; payment via T/T, PayPal, or credit card
For urgent requirements or bulk orders (>5 units), contact us directly at +0086 19859288691 for priority sourcing.
Replacement & Compatibility FAQ
Q: Can I replace a 1747-L551 with a 1747-L552 without reprogramming?
A: Yes. The 1747-L552 is program-compatible with the 1747-L551. Upload your existing program via RSLogix 500, verify I/O configuration, and download to the new processor. No logic changes are required for memory-equivalent programs.
Q: Is the 1747-L551 still in production?
A: Rockwell Automation has announced end-of-life for the SLC 500 platform. The 1747-L551 is no longer manufactured but remains available as new-old-stock (NOS) and refurbished units. Konmask maintains inventory for MRO continuity.
Q: What is the migration path from SLC 5/05 to CompactLogix?
A: Rockwell provides a SLC 500 to CompactLogix Migration Guide. The process involves converting RSLogix 500 programs to Studio 5000 format, remapping I/O to 1769 modules, and re-validating the application. Konmask can assist with migration planning.
Q: Can the 1747-L551 communicate with third-party SCADA systems?
A: Yes. Via its native EtherNet/IP port, the 1747-L551 is compatible with any SCADA platform supporting EtherNet/IP or Modbus TCP (with gateway). Ignition, Wonderware, and iFIX are commonly used.
Q: What power supply is required?
A: The 1747-L551 requires a 1746-series power supply (e.g., 1746-P2 for 24VDC input or 1746-P4 for 120/240VAC). Power supply selection depends on chassis size and total I/O load.
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