Product Overview
The Allen-Bradley 1769-L31 is a CompactLogix Programmable Automation Controller (PAC) engineered for small to medium-scale industrial applications. As part of the 1769 CompactLogix family, this controller delivers dependable logic execution, flexible I/O expansion, and dual serial communication capabilities. With 512 KB of user memory and support for up to 16 local I/O modules across 3 banks, the 1769-L31 serves as a robust control solution for machine builders and system integrators.
This module is manufactured by Rockwell Automation under the Allen-Bradley brand, ensuring high reliability and long-term availability. The 1769-L31 is available in Series A and B, offering compatibility with existing CompactLogix installations.
Key Features & Benefits
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Dual RS-232 Ports: Two serial communication channels support DF1, DH-485, and ASCII protocols, with channel 0 fully isolated for noise immunity.
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512 KB User Memory: Ample space for control programs, data tables, and recipe management.
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Expandable I/O: Supports up to 16 local I/O modules and 3 I/O banks, allowing scalable system design.
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Flexible Mounting: DIN-rail or panel mounting with an open-style enclosure for easy integration.
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Diagnostic LEDs: RUN, FORCE, BAT, OK, I/O, and channel status indicators simplify troubleshooting.
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Non-Volatile Memory Option: Use 1784-CF64 or 1784-CF128 CompactFlash cards for program backup.
Technical Specifications
| Parameter |
Value |
| Part Number |
1769-L31 |
| Product Line |
CompactLogix |
| Module Type |
Control Module |
| Memory |
512 kilobytes |
| Communication Ports |
Two (2) RS-232 |
| Channel Isolation |
Channel 0: Fully isolated; Channel 1: Non-isolated |
| Supported Protocols |
DH485; DF1; ASCII |
| Max I/O Modules |
16 Modules |
| Max I/O Banks |
3 banks |
| Power Supply Distance Rating |
1747-CP3 / 1756-CP3 |
| Battery |
1747-BA |
| Vibration |
Operating: 10 to 500 Hz, 5G, 0.030 in. peak-to-peak |
| Operating Temperature |
0° to +60°C (+32° to +140°F) |
| Enclosure Type |
None (Open Style) |
| Series |
A and B |
| Shipping Weight |
2 lbs. |
| Shipping Dimensions |
8 x 8 x 5 inch |
| Wire Type |
Copper – 90°C |
| Wire Size (Solid) |
22-14 AWG |
| UPC |
10612598313652 |
Industry Applications
The 1769-L31 excels in applications requiring reliable sequential control and moderate I/O counts. Common use cases include:
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Packaging Machinery: Control of conveyors, labeling stations, and wrapping equipment.
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Material Handling: Coordination of sorters, lifts, and transfer lines.
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Process Skids: Monitoring and control of pumps, valves, and sensors in small process units.
Because the 1769-L31 supports up to 16 local I/O modules and 3 I/O banks, it scales efficiently as production demands grow, reducing the need for a full controller upgrade.
Installation & Setup Guidance
Mount the 1769-L31 on a DIN rail or panel using the open-style enclosure. Position the controller as the leftmost module in the CompactLogix system and ensure it sits within four modules of the power supply. Use the 1756-CP3 or 1747-CP3 serial cable for programming and communication wiring, and connect solid copper wire sized 22-14 AWG rated for 90°C. Always install the 1747-BA battery to maintain user memory during power loss. For non-volatile storage, insert a 1784-CF64 or 1784-CF128 CompactFlash card.
Maintenance & Reliability
Routine maintenance focuses on verifying battery health and checking for loose wiring. The BAT LED indicates when the 1747-BA battery needs replacement, ensuring program memory remains intact. Periodically inspect the controller for dust accumulation and ensure the operating temperature stays within 0° to +60°C. With proper care, the 1769-L31 delivers long service life and minimal downtime, making it a cost-effective choice for continuous operations.
Compatibility & Integration
The 1769-L31 integrates seamlessly with other CompactLogix components and supports DH-485, DF1, and ASCII protocols through its dual RS-232 ports. It pairs with 1769 I/O modules and is compatible with Rockwell Automation programming software. For system expansion, the controller supports up to 16 local I/O modules and 3 I/O banks. The battery (1769-BA) and serial cables (1756-CP3 or 1747-CP3) are specifically designed for this controller.
Selection Guide & Purchasing Advice
Before purchasing a 1769-L31, verify your system requirements: number of I/O points, communication needs, and memory capacity. Ensure the controller’s 512 KB memory and dual serial ports match your application. Confirm the operating environment stays within the specified temperature and vibration limits. When sourcing this module, rely on a reputable supplier like PLC Source PRO to guarantee authentic Allen-Bradley components and reliable after-sales support.