Product Introduction
The Allen-Bradley 1756-L85EP is a ControlLogix 5580E Process Controller engineered for demanding process automation applications. As part of the ControlLogix family, this controller delivers high-performance processing with integrated Ethernet connectivity, making it a core component for modern industrial control systems.
With 40 Megabytes of user memory and support for up to 300 EtherNet/IP devices, the 1756-L85EP provides the capacity and speed needed for complex processes. Its built-in USB 2.0 port (12 Mbps) and 1GB Ethernet port simplify programming and network integration, while the 4-character alphanumeric display offers at-a-glance status information.
Supported in the Studio 5000 Automation Engineering and Design Environment, this controller streamlines development and maintenance workflows, reducing engineering time and improving overall system reliability.
Technical Specifications
Below are the key specifications for the Allen-Bradley 1756-L85EP, providing a clear understanding of its capabilities:
| Specification |
Value |
| Brand |
Allen-Bradley / Rockwell Automation |
| Series |
ControlLogix |
| Part Number |
1756-L85EP |
| Product Type |
Controller |
| Compatibility |
ControlLogix 5580 |
| Ethernet Speeds |
10/100/1000 Mbps |
| USB Speed |
12 Mbps |
| User Memory |
40 Megabytes |
| Maximum Total I/O |
128,000 |
| Maximum Digital I/O |
128,000 |
| Maximum Analog I/O |
4,000 |
| Power Dissipation |
6.2 Watts |
| Thermal Dissipation |
21.2 BTU per hour |
These figures highlight the controller's ability to handle large-scale I/O counts while maintaining efficient power usage—critical for minimizing operational costs.
Real-World Applications
The 1756-L85EP excels in process industries such as oil and gas, chemical, and food and beverage, where precise control and high availability are essential. Its 128,000 maximum total I/O makes it suitable for applications with extensive field instrumentation, including analog loops and discrete devices.
For example, in a chemical batch process, the controller can manage multiple recipe phases simultaneously, coordinating hundreds of analog inputs and outputs with millisecond-level accuracy. The integrated Ethernet port enables direct connection to plant networks, facilitating data exchange with MES/ERP systems and simplifying remote monitoring.
The controller's support for up to 300 EtherNet/IP devices allows seamless integration with smart sensors, drives, and remote I/O, providing a scalable architecture that grows with your operation.
Installation & Setup Guidance
Installing the Allen-Bradley 1756-L85EP requires a ControlLogix Series C chassis for full performance. It can also be used in a Series B chassis, but with a derated temperature range—so plan your cabinet cooling accordingly. The module draws power directly from the chassis power supply, eliminating the need for external wiring.
Mount the controller vertically in any slot of the chassis. Ensure adequate airflow around the module to maintain the operating temperature range of 32 to 140 degrees Fahrenheit. For Series C chassis, keep surrounding air temperature below 140 degrees Fahrenheit. Maintain relative humidity between 5% and 95% to prevent condensation.
Connect the Ethernet cable to the 1GB port for network communication. Use the USB port (12 Mbps) for local programming or firmware updates. After power-up, configure the controller using Studio 5000 software to set IP addresses and communication parameters.
Maintenance & Reliability
The 1756-L85EP is designed for long service life with minimal maintenance. Its open enclosure design and compliance with T4 ATEX temperature code rating ensure safe operation in hazardous areas. The controller's vibration rating of 2 g at 10 to 500 Hertz and shock rating of 30 g (both operating and non-operating) guarantee robustness in industrial environments.
To maximize reliability, periodically inspect the chassis air filters and ensure ambient temperature stays within limits. Check network connections for loose cables or corrosion. The controller's low power dissipation (6.2 Watts) reduces heat buildup, extending component life and lowering cooling costs—an important factor for total cost of ownership.
Compatibility & Integration
This controller is part of the ControlLogix 5580 family and is fully compatible with the Studio 5000 environment. It supports direct Ethernet communication without a bridge module, simplifying network design. With 300 EtherNet/IP device support, you can integrate a wide range of industrial devices, including drives, smart sensors, and remote I/O modules.
The USB port enables quick local access for programming and diagnostics, while the Ethernet port provides high-speed data exchange (10/100/1000 Mbps) for real-time control and monitoring. The controller's compatibility with ControlLogix Series C (and Series B with derating) ensures it fits into existing infrastructures.
Buying Guide
Before purchasing the Allen-Bradley 1756-L85EP, verify your chassis type and available slots. Confirm that your existing power supply can handle the module's current requirements (1.2 Amps at 5 VDC and 5 milliamps at 1.2 VDC). Ensure your software version supports this controller model.
For a reliable source, consider PLC Source PRO, which offers genuine industrial automation parts with expert support. When ordering, double-check the part number to avoid compatibility issues, and plan for any necessary accessories like cables or mounting hardware.