Logix5550 512KB Controller 1756-L1M1 Allen Bradley

Product Overview

The Allen-Bradley 1756-L1M1 is a ControlLogix 5550 controller with integrated 512 KB expansion memory. It provides 500 KB of data and logic memory plus 150 KB of I/O memory for control applications, representing the original generation of ControlLogix processors.

Key Specs

• Data and logic memory: 500 KB
• I/O memory: 150 KB
• Expansion memory: 512 KB integrated (M1)
• Non-volatile memory: None (requires battery backup)
• Backplane current: 950 mA @ 5.1 V DC, 20 mA @ 24 V DC
• Power dissipation: 4.6 W
• Weight: 0.35 kg (12.5 oz)
• Programming cable: 1756-CP3 or 1747-CP3 serial cable

Why Choose This

• Proven reliability in legacy ControlLogix installations
• Integrated expansion memory eliminates separate memory board installation
• Compatible with original 1756 I/O and communication modules
• Battery-backed memory retains program during power loss

Common Questions

• What battery does the 1756-L1M1 use? The 1756-BA1 lithium battery (0.59 g) is the compatible replacement.
• Which software programs this controller? RSLogix 5000 version compatible with ControlLogix 5550 controllers.
• Is it still supported? The 1756-L1M1 is a legacy controller available through surplus channels for maintaining existing installations.

Mounting Steps

1. Install the controller in any available slot of the 1756 chassis.
2. Connect the 1756-CP3 serial cable to the programming port.
3. Install a fresh 1756-BA1 battery before commissioning.
4. Configure the controller in RSLogix 5000 and download the application.
5. Verify the controller status indicators show normal operation.

Buying Advice

• Select the 1756-L1M1 for maintaining or expanding legacy ControlLogix 5550 systems.
• For new installations, consider the 1756-L71 or later ControlLogix 5570 series controllers.
• Stock spare 1756-BA1 batteries as part of routine maintenance for this controller.