Product Overview for the 1756-L65 ControlLogix Processor

The 1756-L65 is a ControlLogix processor from Allen-Bradley. Firstly, this module is manufactured by Rockwell Automation under the Allen-Bradley brand. Specifically, the 1756-L65 belongs to Series B of the ControlLogix controllers. In addition, this controller has an inbuilt RS-232 serial port for local communication. The processor provides 32 MB of user memory for both data and logic storage. It also includes 478 KB of dedicated I/O memory. Consequently, the 1756-L65 handles large control applications with substantial program and data requirements. Therefore, this processor is ideal for factory automation and process control systems.

Memory Architecture

32 MB User Memory
The 1756-L65 offers substantial memory capacity for complex control programs. Firstly, the user memory is 32 MB for storing both logic and data. In addition, the dedicated I/O memory is 478 KB for handling large I/O configurations. Specifically, this memory architecture separates program storage from I/O image management. Consequently, the 1756-L65 accommodates sophisticated control strategies without memory conflicts. Therefore, you can implement extensive data logging, recipes, and complex algorithms.

Nonvolatile Memory Storage Option
The 1756-L65 supports optional nonvolatile memory storage for program backup. Firstly, you can install a 128 MB CompactFlash memory card (model 1756-CF128) for removable storage. In addition, this nonvolatile memory retains the control program without battery power. Specifically, the CompactFlash card is useful for program distribution and disaster recovery. Consequently, the 1756-L65 provides flexible program backup options for different application needs.

Battery-Backed Memory
The 1756-L65 uses a replaceable battery for memory retention during power loss. Firstly, the compatible battery is the 1756-BA2 lithium battery. In addition, the battery should only be replaced when required, not on a fixed schedule. Specifically, the battery preserves user memory and I/O memory contents when the controller is powered off. Consequently, the 1756-L65 maintains program integrity during power outages and maintenance shutdowns.

I/O Capacity and System Configuration

128,000 Total I/O Capacity
The 1756-L65 handles massive I/O counts for large control systems. Firstly, the maximum total I/O is 128,000 discrete input and output signals. In addition, the maximum digital I/O is also 128,000 points for discrete control. Specifically, the maximum analog I/O is 4,000 channels for process measurement and control. Consequently, the 1756-L65 controls entire production facilities from a single processor. Therefore, system architecture remains simple even for very large applications.

Compatible ControlLogix Chassis
The 1756-L65 installs into standard ControlLogix chassis models. Firstly, compatible chassis include the 1756-A4, 1756-A7, 1756-A10, 1756-A13, and 1756-A17. In addition, the processor occupies a single slot in any of these chassis. Specifically, the 1756-L65 can be installed in any slot of the chassis. Consequently, this processor offers flexible mounting options for various system configurations. Therefore, you can position the controller optimally for your specific layout.

Controller Connections
The 1756-L65 supports up to 250 controller connections for extensive networking. Firstly, each connection represents a communication path to another device or network. In addition, this high connection count supports large distributed control systems. Specifically, connections are shared across all communication interfaces and protocols. Consequently, the 1756-L65 integrates with many HMIs, drives, and remote I/O racks simultaneously.

Communication Capabilities

Built-in RS-232 Serial Port
The 1756-L65 includes an integrated RS-232 serial port for flexible communication. Firstly, this port supports DF1 radio modem protocol for wireless connectivity. In addition, it supports DF1 full-duplex and DF1 half-duplex for point-to-point links. Specifically, ASCII protocol is available for communication with barcode readers and serial printers. The port also supports DH-485 networking and Modbus via logic programming. Consequently, the 1756-L65 connects to a wide variety of serial devices without additional modules.

Supported Network Protocols
The 1756-L65 supports numerous industrial communication protocols. Firstly, EtherNet/IP provides high-speed plant-wide networking for control and information. In addition, ControlNet supports deterministic I/O control and real-time messaging. Specifically, DeviceNet connects to smart sensors, actuators, and drives. Other supported protocols include Data Highway Plus (DH+), Remote I/O (RIO), SynchLink, and third-party process networks. Consequently, the 1756-L65 integrates into virtually any industrial network architecture.

Controller Tasks and Execution

Multi-Task Processing Architecture
The 1756-L65 supports a robust multitasking environment. Firstly, the controller handles up to 32 independent tasks for organized program execution. In addition, each task can contain up to 100 programs for modular logic design. Specifically, event tasks accept all event triggers for time-critical responses. Consequently, the 1756-L65 executes high-priority control loops without interruption from lower-priority tasks. Therefore, motion control and fast process loops maintain deterministic performance.

Scan Time Consideration
The 1756-L65 may have slower scanning than other ControlLogix 1756-L6x controllers. Firstly, when the same project is loaded to different controllers, scan time differences become apparent. In addition, the 1756-L65 is optimized for memory capacity rather than raw speed. Specifically, this controller prioritizes large program storage over execution speed. Consequently, the 1756-L65 is best suited for applications where memory is more critical than scan time. Therefore, select this processor for large, complex programs that do not require the fastest execution.

Power and Environmental Specifications

Current Draw and Thermal Dissipation
The 1756-L65 consumes moderate power for its memory capacity. Firstly, the current draw at 5.1 Volts DC is 1200 milliamperes (1.2 Amps). In addition, the current draw at 24 Volts DC is only 14 milliamperes. Specifically, the power dissipation is 3.5 Watts. The thermal dissipation is 11.9 BTU per hour. Consequently, the 1756-L65 adds moderate heat to the control cabinet. Therefore, adequate ventilation should be provided in densely populated chassis.

Isolation and Testing
The 1756-L65 provides robust electrical isolation for system protection. Firstly, the continuous isolation voltage is 30 Volts DC for basic insulation. In addition, the controller has been type-tested for 60 seconds at 720 Volts DC. Specifically, this testing verifies insulation integrity under high-voltage conditions. Consequently, the 1756-L65 withstands electrical noise and transient voltages. Therefore, the processor protects sensitive backplane circuits from field wiring faults.

Technical Specifications of the 1756-L65

General Specifications

• Manufacturer: Rockwell Automation.

• Brand: Allen-Bradley.

• Part Number / Catalog No.: 1756-L65.

• Series: ControlLogix (Series B).

• Module Type: Processor Module.

• Enclosure: None (Open-Style).

• UPC: 10612598340726.

Memory Specifications

• User Memory: 32 MB (for data and logic).

• I/O Memory: 478 Kilobytes.

• Nonvolatile Memory Option: 1756-CF128 (128 MB CompactFlash).

• Battery Type: 1756-BA2 lithium battery (replaceable as needed).

I/O Capacity Specifications

• Maximum Total I/O: 128,000.

• Maximum Digital I/O: 128,000.

• Maximum Analog I/O: 4,000.

Controller Task Specifications

• Maximum Tasks: 32.

• Maximum Programs per Task: 100.

• Event Task Support: All event triggers.

• Maximum Controller Connections: 250.

Communication Specifications

• Integrated Port: RS-232 Serial Port.

• Serial Protocols: DF1 radio modem, DF1 full/half-duplex, ASCII, DH-485, Modbus via logic.

• Supported Networks: EtherNet/IP, ControlNet, DeviceNet, DH+, Remote I/O, SynchLink, third-party networks.

Power Specifications

• Current Draw (5.1 Volts DC): 1200 milliamps (1.2 A).

• Current Draw (24 Volts DC): 14 milliamps.

• Power Dissipation: 3.5 Watts.

• Thermal Dissipation: 11.9 BTU per hour.

Isolation Specifications

• Continuous Isolation Voltage: 30 Volts DC.

• Type Test: 60 seconds at 720 Volts DC.

Physical Specifications

• Slot Width: 1 slot.

• Compatible Chassis: 1756-A4, 1756-A7, 1756-A10, 1756-A13, 1756-A17.

Environmental Specifications

• Operating Temperature: 0 to 60 degrees Celsius.

• Storage Temperature: -40 to 85 degrees Celsius.

• Maximum Surrounding Air Temperature: 60 degrees Celsius.

• Relative Humidity: 5% to 95% non-condensing.

• Vibration (10 to 500 Hz): 2 g.

• Operating Shock: 30 g.

• Non-Operating Shock: 50 g.

Installation Guide for the 1756-L65

Follow these steps for a proper installation of the 1756-L65.

Step 1: Chassis Selection and Preparation
Firstly, select a compatible ControlLogix chassis for the 1756-L65. Compatible models include 1756-A4, 1756-A7, 1756-A10, 1756-A13, or 1756-A17. Then, ensure the chassis is mounted securely and properly grounded.

Step 2: Power Supply Installation
After that, install a compatible ControlLogix power supply in the leftmost slot of the chassis. The power supply must provide adequate current for the 1756-L65 and all I/O modules. Verify that the 5.1V DC capacity meets the 1200 mA requirement of the processor.

Step 3: Processor Installation
Then, insert the 1756-L65 into the desired slot of the 1756 chassis. The processor can be installed in any slot. Align the module with the card guides on the top and bottom. Push firmly until the module seats completely in the backplane connector. Secure the processor using the retaining screws.

Step 4: Battery Installation
Furthermore, install a 1756-BA2 lithium battery into the 1756-L65 if not already installed. The battery preserves memory during power loss. Replace the battery only when required, not on a fixed schedule.

Step 5: CompactFlash Installation (Optional)
If nonvolatile memory storage is desired, insert a 1756-CF128 CompactFlash card into the designated slot. This card provides 128 MB of removable program storage. Then, apply power to the 1756-L65 and the ControlLogix system. Configure the processor using RSLogix 5000 or Studio 5000 software.

Packaging List for the 1756-L65

• 1756-L65 ControlLogix Processor Module (1 unit)

• 1756-BA2 lithium battery (installed)

• Product documentation and installation guide (1 copy)

Note: CompactFlash memory card 1756-CF128 is optional and sold separately.

Frequently Asked Questions (FAQs) About the 1756-L65

Q1: How much user memory does the 1756-L65 have?

The 1756-L65 has 32 MB of user memory for data and logic storage. In addition, it has 478 KB of dedicated I/O memory. Therefore, this processor handles large, complex control applications with extensive data requirements.

Q2: What type of battery does the 1756-L65 use?

The 1756-L65 uses a 1756-BA2 lithium battery. This battery is replaceable but only when required. Therefore, no scheduled battery replacement is necessary. Replace the battery when the low battery indicator activates.

Q3: What is the maximum I/O capacity of the 1756-L65?

The 1756-L65 supports up to 128,000 total I/O points. This includes 128,000 digital I/O and 4,000 analog I/O channels. Consequently, this processor controls very large automation systems from a single controller.

Q4: What communication protocols does the 1756-L65 support?

The 1756-L65 supports EtherNet/IP, ControlNet, DeviceNet, Data Highway Plus, Remote I/O, SynchLink, and third-party networks. In addition, the built-in RS-232 port supports DF1, ASCII, DH-485, and Modbus via logic. Therefore, this processor connects to diverse devices and networks.

Q5: How many controller connections does the 1756-L65 support?

The 1756-L65 supports up to 250 controller connections. This high connection count supports large distributed control systems. Therefore, you can connect many HMIs, drives, and remote I/O racks to a single processor.