Allen-Bradley 1756-L81EXT Controller ControlLogix-XT

Allen-Bradley 1756-L81EXT ControlLogix-XT Controller for Harsh Environments

1756-L81EXT Product Introduction

The Allen-Bradley 1756-L81EXT is a ruggedized controller from the ControlLogix-XT series. This unit is designed for corrosive and harsh environments. A conformal coating protects all internal components. Therefore, the 1756-L81EXT operates reliably where standard controllers would fail.

Moreover, this controller functions identically to conventional ControlLogix controllers. You get the same programming flexibility and communication options. The only difference is the added physical protection. This makes the 1756-L81EXT perfect for chemical plants, offshore platforms, and wastewater treatment facilities.

1756-L81EXT Technical Specifications

Memory and Processing Power
User memory measures 3 MB. The controller handles 32 controller tasks. Each task supports up to 1000 programs. Local I/O event triggers are unlimited. This processing power suits complex automation sequences.

Communication Ports
The 1756-L81EXT includes integral communication ports. One USB port supports local programming. One embedded Ethernet port enables network connectivity. Additionally, the controller supports multiple network protocols:

• Ethernet/IP

• Remote Input/Output

• Data Highway Plus

• DeviceNet

• ControlNet

• SynchLink

• Third-party process and device networks

Programming Languages
You can program this controller using several languages:

• Relay ladder logic

• Structured text

• Function block diagram

• Sequential function chart

Environmental and Electrical Data

Temperature Ratings
When used standalone, the 1756-L81EXT operates from -25°C to 70°C. When used with Flex I/O-XT series products, the range is -20°C to 70°C. This wide range suits extreme climate conditions.

Power Requirements
Minimum current draw is 5 mA at 1.2V DC. Maximum current draw reaches 1.2 A at 5.1V DC. Thermal dissipation measures 21.2 BTU/hour. Plan your chassis power budget accordingly.

Conformal Coating Protection
A conformal coating adds a protective layer over circuit boards. This coating resists moisture, dust, chemicals, and corrosion. Consequently, the 1756-L81EXT lasts longer in aggressive environments.

Installation Guidelines

First, verify your chassis compatibility. Operators using LXT chassis should upgrade to the K version chassis. Next, install the 1756-L81EXT into any ControlLogix chassis slot. The controller automatically detects the backplane.

Furthermore, connect the Ethernet port to your industrial network. Use the USB port for local firmware updates. Ensure proper grounding before applying power. Finally, download your program using Studio 5000 software.

Chassis Upgrade Note

Users who have the LXT chassis need an upgrade. Moving to the K version chassis is recommended. This ensures full compatibility with the 1756-L81EXT controller. Contact technical support for upgrade guidance.

Packaging List

• 1 x Allen-Bradley ControlLogix-XT controller (1756-L81EXT)

• 1 x Conformal coated unit with factory labels

• 1 x Anti-static protective bag

• 1 x Factory cardboard box

Shipping Information

All orders ship via FedEx, UPS, or DHL. Delivery typically takes 3 to 7 business days.

Frequently Asked Questions (FAQ)

1. What makes the 1756-L81EXT different from the standard 1756-L81?
The 1756-L81EXT has a conformal coating that protects against corrosion and moisture. The standard version lacks this coating. Performance and memory remain identical.

2. Can I use the 1756-L81EXT in a non-harsh environment?
Yes, absolutely. The controller works perfectly in clean environments too. The conformal coating only adds protection. It never reduces performance or reliability.

3. What software do I need to program the 1756-L81EXT?
You need Studio 5000 software. The same software used for standard ControlLogix controllers works for the 1756-L81EXT.

4. Does the conformal coating affect repair or rework?
Yes, repairs become more difficult. The coating must be removed before component-level rework. Most users replace the entire unit instead of repairing it.

5. Is the 1756-L81EXT compatible with standard ControlLogix I/O modules?
Yes, it works with all standard ControlLogix I/O modules. However, for full XT system protection, use XT-rated I/O modules and chassis.