Product Overview

The Allen-Bradley 1756-L1M3 is a ControlLogix 5550 controller. This processor module belongs to the ControlLogix series of programmable automation controllers. It provides 2 MB of user memory for data and logic.

The controller has 150 KB of I/O memory. However, it does not come with a nonvolatile memory or an enclosure system. Therefore, a battery is required to retain programs during power loss.

General Specifications

The 1756-L1M3 offers robust processing capabilities for ControlLogix systems.

• Manufacturer: Rockwell Automation.

• Brand: Allen-Bradley.

• Series: ControlLogix (5550 series).

• Part Number/Catalog No.: 1756-L1M3.

• Module Type: Processor Module.

• User Memory (Expansion): 2 MB.

• I/O Memory: 150 KB.

• Enclosure: Open (no built-in enclosure).

• Weight: 0.36 grams (12.7 ounces) – Note: weight appears to be 0.36 kg (12.7 oz) based on typical values.

• UPC: 10612598181008.

Power and Backplane Current

The 1756-L1M3 draws power from the ControlLogix backplane.

• Peak Backplane Current (5.1 Volts DC): 1.20 Amps.

• Peak Backplane Current (24 Volts DC): 0.02 Amps (20 milliamps).

• Backplane Current at 5 Volts: 120 milliamps (typical).

• Backplane Current at 24 Volts: 2 milliamps (typical).

• Average Power Dissipation: 5.4 Watts.

• Average Thermal Dissipation: 18.4 BTU/hour.

• Power Dissipation (Max at 60°C): 4.1 Watts.

Isolation and Dielectric Withstand

The 1756-L1M3 provides robust electrical protection.

• Isolation Voltage: 30 Volts continuous.

• Dielectric Withstand Tested: 500 Volts for 60 seconds.

Environmental Specifications

The 1756-L1M3 withstands typical industrial conditions.

Temperature Ranges:

• Operating Temperature: 0 to 60°C (32 to 140°F).

• Storage Temperature: -40 to 85°C (-40 to 185°F).

Humidity:

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

Vibration:

• Operating Vibration: 2.0 G maximum peak acceleration at 10 to 500 Hertz.

Shock:

• Operating Shock: 30 G peak for 11 milliseconds.

• Storage Shock: 50 G peak for 11 milliseconds.

Input Current Specifications

The 1756-L1M3 has defined input current characteristics.

• Minimum Operating Current: 2 milliamps at 10 Volts DC.

• Maximum Operating Current: 3.5 milliamps at 30 Volts DC.

• Maximum Input Current, Off-State: 1.5 milliamps.

EMC Immunity Specifications

The 1756-L1M3 offers robust immunity to electrical disturbances.

• ESD Immunity: 6 kV contact discharges, 8 kV air discharges.

• Radiated RF Immunity: 10 Volts/m with 1 kHz sine-wave 80% AM from 30 MHz to 1000 MHz; 10 Volts/m with 200 Hz 50% Pulse 100% AM at 900 MHz.

• EFT/B Immunity: ±4 kV at 2.5 kHz on power ports; ±2 kV at 5 kHz on communication ports.

• Conducted RF Immunity: 10Vrms with 1 kHz sine-wave 80% AM from 150 kHz to 80 MHz.

Emissions Classification

The 1756-L1M3 meets specific emissions standards.

• Emissions Classification: Group 1, Class A.

• Characteristics: Group 1 and Class 1 emissions.

Compatible Accessories

The 1756-L1M3 works with specific accessories.

Removable Terminal Blocks:

• 1756-TBCH.

• 1756-TBS6H.

Programming Cables:

• 1756-CP3 (serial cable, category 3).

• 1747-CP3 (serial cable).

Replacement Battery:

• 1756-BA1 (0.59g lithium battery only).

Key Features

The 1756-L1M3 offers several advantages for control applications.

2MB User Memory:
Provides substantial memory for large control programs. Therefore, it suits complex automation applications.

High I/O Capacity:
Supports up to 128,000 I/O points (compatible with ControlLogix architecture). Consequently, it handles large-scale systems.

Fast Scan Performance:
Typical ControlLogix scan times support high-speed control. Hence, it meets demanding process requirements.

Multiple Network Support:
Communicates over ControlNet, EtherNet/IP, and other networks via backplane. Thus, it integrates into diverse systems.

Battery-Backed Memory:
Uses 1756-BA1 lithium battery for program retention. Therefore, programs are preserved during power outages.

Wide Operating Temperature:
Operates from 0 to 60°C. For this reason, it suits industrial control rooms and enclosures.

Compact Form Factor:
Lightweight design at approximately 0.36 kg. Consequently, it adds minimal load to the backplane.

Open Enclosure Design:
Requires installation in a protected panel or enclosure. Hence, it is suitable for UL/cUL listed panels.

Robust EMC Immunity:
High immunity to ESD, radiated RF, EFT/B, and conducted RF. Thus, it operates reliably in noisy industrial environments.

Typical Applications

The 1756-L1M3 suits various control applications.

• Large-scale manufacturing process control.

• High-I/O count automation systems.

• ControlLogix platform upgrades and expansions.

• Multi-network integration projects.

• Applications requiring open-enclosure mounting.

Installation Guidelines

Install the 1756-L1M3 in any slot of a ControlLogix chassis (typically slot 0). First, ensure the chassis power supply can provide the required backplane currents. Then, insert the processor into the slot.

Install a 1756-BA1 lithium battery for program retention. Connect programming devices via 1756-CP3 or 1747-CP3 serial cables. The open enclosure requires installation within a protected panel or cabinet.

The operating temperature range is 0 to 60°C. The relative humidity must be non-condensing between 5% and 95%. The module has no nonvolatile memory, so the battery is essential.

What is in the Box

Please inspect all items upon delivery.

• Allen-Bradley 1756-L1M3 ControlLogix 5550 processor module.

• Installation instruction manual.

• Anti-static protective bag.

Note: Battery (1756-BA1) and removable terminal blocks (1756-TBCH or 1756-TBS6H) are sold separately.

Frequently Asked Questions (FAQ)

1. How much user memory does the 1756-L1M3 have?

The 1756-L1M3 provides 2 MB of user memory. It also has 150 KB of I/O memory.

2. Does this processor include nonvolatile memory?

No. The 1756-L1M3 does not come with nonvolatile memory. Therefore, a 1756-BA1 battery is required to retain the program during power loss.

3. What is the operating temperature range of this processor?

The 1756-L1M3 operates from 0 to 60°C (32 to 140°F). Storage temperature ranges from -40 to 85°C.

4. What battery is compatible with this module?

The 1756-L1M3 uses the 1756-BA1 lithium battery only. The battery weighs 0.59 grams.

5. What emissions classification does this controller have?

The 1756-L1M3 has Group 1, Class A emissions classification. Consequently, it is suitable for industrial environments.