Product Overview
The Allen-Bradley 1785-L40E is a high-performance Programmable Logic Controller (PLC) from the trusted PLC-5 family. Designed for medium to large-scale automation applications, this industrial automation module interfaces simultaneously with a wide range of devices, making it a versatile backbone for machine and process control systems. With 48K words of user memory and support for up to 2048 I/O points, the 1785-L40E delivers robust processing power for demanding industrial environments.
Installed in a 1771 chassis, the 1785-L40E utilizes the electronic backplane for power distribution and communication with other modules. It supports multiple chassis configurations, including local and remote I/O, ensuring flexible system scaling. Whether upgrading an existing line or building a new control system, the 1785-L40E offers proven reliability and performance.
Technical Specifications
The following specifications are directly from the manufacturer's data and define the operational capabilities of the 1785-L40E.
| Attribute |
Value |
| Manufacturer |
Rockwell Automation |
| Part Number |
1785-L40E |
| Product Type |
Programmable Logic Controller |
| Product Family |
PLC-5 |
| Processor |
PLC-5/40E |
| Max User Memory Words |
48 Kilowords |
| Battery-Backed Static RAM |
Yes |
| EEPROM Program Backup Option |
Yes (using 1785-ME16, -ME32, -ME64, -M100) |
| Max Total I/O |
2048 (any mix) or 2048 in + 2048 out (complementary) |
| Max Analog I/O |
2048 |
| Maximum Number of I/O per Link |
32 |
| I/O Scan Time Per Rack |
10 ms at 57.6 kbits/s, 7 ms at 115.2 kbits/s, 3 ms at 230.4 mbits/s |
| Max I/O Chassis Total |
61 |
| Max I/O Chassis Universal Remote |
60 |
| Max I/O Chassis Extended Local |
0 |
| Embedded Communication Interfaces |
4 DH+/Remote I/O (Adapter or Scanner), 1 serial port (RS-232/423/422A), 1 Ethernet |
| Backplane Current Load |
3.3A |
| Power Dissipation |
17.3W |
| Power Supply |
1771-P4S, -P6S, -P4S1, -P6S1 |
| Operating Temperature |
0...60 °C (32...140 °F) |
| Non-Operating Temperature |
–40...85 °C (–40...185 °F) |
| Battery |
1770-XYC |
| Weight |
Approximately 1.38 kg (3.0 lb) |
Key Features & Benefits
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High Memory Capacity: 48K words of user memory accommodates complex programs and data logging.
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Flexible I/O Configuration: Supports 2048 any mix or complementary I/O (2048 in + 2048 out), adapting to diverse application needs.
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Multi-Protocol Communication: Embedded DH+, Remote I/O, serial (RS-232/423/422A), and Ethernet ports enable seamless integration with various networks.
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Rugged Design: Operates reliably in temperatures from 0 to 60 °C, suitable for harsh industrial settings.
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Battery Back-up: Includes 1770-XYC battery for memory retention during power loss.
Industry Applications
The 1785-L40E is ideal for applications that require robust control and flexibility. Typical use cases include:
-
Manufacturing Assembly Lines: Coordinating multiple stations with discrete and analog I/O, using the 1785-L40E's fast scan times to maintain throughput.
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Material Handling Systems: Managing conveyors, sorters, and robotic interfaces via DH+ and Remote I/O networks for real-time control.
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Process Control: Implementing PID algorithms for temperature, pressure, or flow control in chemical or food processing plants.
Its ability to handle up to 61 chassis and 2048 I/O points makes it a scalable solution for expanding operations.
Installation & Setup
Proper installation ensures optimal performance and longevity. Follow these guidelines:
- Mount the 1785-L40E in a compatible 1771 chassis (e.g., 1771-A1B, -A2B, -A3B, -A3B1, -A4B).
- Use a compatible power supply (1771-P4S, -P6S, -P4S1, -P6S1) to provide the required backplane current (3.3A).
- Connect communication cables to the appropriate ports: DH+/RIO, serial, and Ethernet.
- Configure the processor using RSLogix 5 or equivalent software, selecting the appropriate I/O addressing mode (2-slot, 1-slot, or half-slot).
- Ensure proper grounding and shielding for communication cables to minimize electromagnetic interference.
Maintenance & Reliability
Routine maintenance helps maximize the lifespan of the 1785-L40E. Key practices include:
- Check the 1770-XYC battery annually and replace it every 3-5 years to prevent memory loss.
- Keep the enclosure clean and free of dust; ensure adequate airflow to maintain operating temperature.
- Inspect connectors and wiring for signs of wear or corrosion.
- Perform periodic backups of the program to EEPROM modules (1785-ME16, -ME32, -ME64, -M100) to safeguard against unexpected failures.
Following these steps reduces downtime and extends service life, delivering long-term cost savings.
Compatibility & Integration
The 1785-L40E integrates seamlessly with other Allen-Bradley controllers and devices. It supports:
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DH+ Networks: Communicate with other PLC-5 processors and HMIs.
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Remote I/O: Connect to 1771 I/O chassis and intelligent I/O modules (8-, 16-, 32-point).
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Ethernet: Enable TCP/IP communication for programming and data exchange.
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Serial: Interface with legacy devices using RS-232, RS-423, or RS-422A standards.
This multi-protocol capability ensures easy integration into existing automation architectures.
Selection Guide & Purchasing Advice
Before purchasing a 1785-L40E, verify your system requirements:
- Confirm memory and I/O needs—this module suits applications requiring up to 48K words and 2048 I/O.
- Check chassis compatibility and available slots.
- Review communication requirements to ensure DH+, RIO, serial, and Ethernet ports meet your needs.
For genuine Allen-Bradley 1785-L40E modules with reliable support, consider PLC Source PRO as a trusted supplier. We offer quality industrial automation parts backed by industry expertise.