Description
Note: Many products are not yet listed. Please contact us for more product information. Our supply channels are constantly expanding, and we currently have 20 stable shared supply channels. Please confirm the model, product, price, and all other necessary information with customer service before placing an order. We offer new, refurbished, and used products, and prices are adjusted according to the year of the item you require.
3. Product Introduction (Anti-Template)
When an older SLC chassis still runs critical machine logic, swapping the processor beats a full platform migration. The 1747-L552 drops into slot 0 of any 1746 chassis and brings 32K words of memory plus a built-in Ethernet port.
That combination lets maintenance teams keep proven code while adding network visibility for HMIs or data collection. Plants that standardized on SLC 5/05 years ago still stock this unit because it preserves both the hardware investment and the existing program structure.
1747-L552
1747-L552
1747-L552
1747-L552
1747-L552
4. Key Technical Specifications
| Parameter | Value |
|---|---|
| User Memory | 32K words (typically 28K program/data + 4K data) |
| Discrete I/O Capacity | Up to 4096 inputs / 4096 outputs |
| Local Analog I/O | Up to 480 points |
| Communication Ports | Channel 1: 10Base-T Ethernet (RJ45); Channel 0: RS-232 |
| Typical Program Scan Time | 0.9 ms per K of user program |
| Bit Execution (XIC) | 0.37 µs |
| Max Chassis / Slots | 3 chassis / 30 slots |
| Backplane Current | 1 A at 5 VDC; 200 mA at 24 VDC |
| Operating Temperature | 0 °C to 60 °C |
| Memory Backup | Lithium battery (1747-BA) + optional Flash EEPROM |
5. Field Application & Technical Pitfalls (The Engineer’s Guide)
This processor commonly controls packaging lines, material-handling systems, and mid-size process skids that still run on the SLC 500 platform. The Ethernet port supports both programming access and limited peer-to-peer messaging without adding a separate communication module.
Three pitfalls appear during replacement:
Series and firmware mismatch – earlier series hardware may not support the full 32K memory or certain Ethernet features; verify the label and FRN before downloading.
Battery state – a depleted lithium battery loses the program on power cycle; always check the BATT LED and replace the 1747-BA if the voltage is marginal.
Project memory allocation – after swapping from a 16K L551, RSLogix 500 may still report the old limit until the processor type is correctly updated and the project recompiled.
One plant installed a surplus L552 and immediately hit memory faults. The project file still carried the L551 configuration; correcting the processor type and forcing a full compile cleared the issue in under ten minutes.
6. Quality Control (QC) SOP & Transparency
- Inbound Verification – OEM labeling, series letter, and serial number are photographed and matched to the packing list; any evidence of prior field use is documented.
- Live Rig Testing – unit is seated in a known-good 1746 chassis, powered, and exercised with a test program that exercises memory, I/O scan, Ethernet link, and RS-232 port.
- Parameter Testing – battery voltage is measured; status LEDs and keyswitch operation are verified; Ethernet link and basic messaging are confirmed.
- Final QA & Packaging – unit is sealed in an anti-static bag with desiccant, fitted with a QC-passed label showing test date and technician ID, then double-boxed for shipment.
7. Frequently Asked Questions (FAQ)
Is the 1747-L552 still supported by Rockwell?
The product is discontinued. Existing units continue to run, but new replacements must come from surplus or refurbished stock. Migration paths to CompactLogix or ControlLogix exist when the time comes.
Can I drop this into a chassis that previously held an L551?
Yes. The physical form factor and backplane interface are identical. Update the processor type in RSLogix 500 and recompile so the project recognizes the full 32K memory.
Does the Ethernet port support 100 Mbps?
Early series units are 10Base-T only. Later series revisions added 10/100 auto-negotiation; check the series letter and firmware revision on the specific unit.
What battery does it use?
The standard backup is the 1747-BA lithium battery. Replace it proactively; a low battery is the most common cause of program loss after a power outage.
What warranty comes with a new-surplus unit?
Twelve months from shipment against defects in materials and workmanship when installed within the published ratings.
How do I confirm the unit is healthy after installation?
Watch the status LEDs (RUN, FAULT, BATT, FORCE, Ethernet). Clear any major faults, verify the program checksum, and confirm Ethernet link status before returning the machine to production.
