Product Overview
The Allen-Bradley 1785-L80B is an enhanced PLC-5 programmable logic controller designed for complex industrial automation. With 100,000 words of user memory and support for up to 3072 I/O points, this processor excels in applications requiring high-density control and robust communication.
Key Features & Benefits
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High Memory Capacity: 100 Kilowords battery-backed static RAM ensures reliable program retention.
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Flexible Communication: Four DH+/Remote I/O ports (channels 1A, 1B, 2A, 2B) plus one serial port (RS-232/423/422A) for versatile connectivity.
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Scalable I/O: Supports up to 32 remote I/O racks and 93 total chassis, accommodating extensive systems.
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Redundancy Support: Built-in controller redundancy for high-availability applications.
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Low Power Dissipation: 12 W power draw and 2.3 A backplane current minimize heat load.
Technical Specifications
| Parameter |
Value |
| Manufacturer |
Rockwell Automation |
| Module Type |
PLC5 Processor |
| Part Number |
1785-L80B |
| Processor |
PLC-5/80 |
| Max User Memory |
100 Kilowords |
| Battery-Backed RAM |
Yes |
| Max Total I/O |
3072 (any mix or 3072 in + 3072 out) |
| Max Analog I/O |
3072 |
| Max I/O Chassis Total |
93 |
| Max I/O Chassis Universal Remote |
32 per I/O link |
| Communication Ports |
4 DH+/RIO (Adapter/Scanner), 1 serial (RS-232/423/422A), 2 programming terminals |
| Protocols |
DF1, ASCII, DH+, RIO |
| Controller Redundancy |
Supported |
| Power Dissipation |
12 W |
| Backplane Current Draw |
2.3 A |
| Battery |
1770-XYC |
| EEPROM Backup |
Yes (1785-ME16/ME32/ME64/M100) |
| I/O Scan Time Per Rack |
10 ms @57.6 kbps, 7 ms @115.2 kbps, 3 ms @230.4 kbps |
Real-World Applications
The 1785-L80B is ideal for manufacturing lines, material handling systems, and process control where high I/O counts and multiple communication protocols are required. Its DH+ capability allows peer-to-peer networking between PLC-5 controllers, while remote I/O scanning enables distributed I/O architectures.
Installation & Setup
Mount the 1785-L80B in a compatible 1771 chassis (e.g., 1771-A1B, A2B, A3B, A4B). Connect the backplane and ensure proper power supply (1770-P1, P45, P5, 1771-PE, P4S1, P6S1, P4R, P6R). Configure channels via programming software, selecting DH+ or RIO modes as needed.
Maintenance & Reliability
Monitor the front-panel BATT indicator; replace the 1770-XYC battery every 2-3 years to preserve memory. Keep the controller free of dust and within specified temperature ranges. Periodic checks of communication cables and connectors prevent intermittent faults.
Compatibility & Integration
The 1785-L80B integrates with 1771 I/O modules, other PLC-5 controllers, and higher-level systems via DH+ or RIO. It supports DF1 and ASCII protocols for serial communication, and its control coprocessor expansion port allows additional functionality.
Buying Guide
When purchasing a 1785-L80B, verify the processor revision and included accessories. PLC Source PRO offers genuine Allen-Bradley modules with fast shipping and warranty support.