Overview
The Allen-Bradley 1756-M2 /A memory module is an expansion memory unit designed for the 1756 ControlLogix series, specifically supporting the original-generation 1756-L1 and related controllers. This 1756-M2 provides 1 megabyte of nonvolatile memory capacity in an open-style enclosure, enabling engineers to expand data and logic storage on legacy ControlLogix platforms.
Key Features
- 1 megabyte of memory capacity with open-style enclosure
- Compatible with 1756-L1, 1756-L1M1, 1756-L1M2, and 1756-L1M3 ControlLogix controllers
- Communicates through ControlNet and EtherNet/IP networks via the ControlLogix backplane
- Reliable nonvolatile memory for persistent data storage across power cycles
- No door enclosure design simplifies installation and integration
Technical Specifications
- Memory Capacity: 1 MB (megabyte)
- Weight: 0.22 kilograms (7.7 ounces)
- Operating Temperature: 0 to 60°C (32 to 140°F)
- Storage Temperature: −40 to 85°C (−40 to 185°F)
- Enclosure Type: Open-style (no door)
- Series: ControlLogix 5550
- Part Status: Discontinued by Manufacturer
Typical Applications
The 1756-M2 expansion memory module is used for various applications within harsh industrial environments. Common uses include:
- Expanding memory on legacy 1756-L1 ControlLogix processors for data logging and recipe storage
- Adding persistent nonvolatile storage to PAC systems running batch processes or complex state machines
- Retrofits and system upgrades in manufacturing, food & beverage, and material handling facilities
- Supporting larger user programs where base processor memory is insufficient
Compatibility & Replacements
Compatible With
- 1756-L1, 1756-M1, 1756-M2, and 1756-M3 memory modules for nonvolatile storage
- ControlNet and EtherNet/IP networks via ControlLogix backplane
- ControlLogix 5550 chassis and ControlLogix 5555 systems (where applicable)
- Studio 5000 Logix Designer programming software (IEC 61131-2 standard)
Replaces / Drop-In Replacement For
- 1756-L1 / -L1M1 / -L1M2 / -L1M3 controllers requiring memory expansion
- Earlier 1756-M2 modules requiring replacement or upgrade
- Note: This unit is discontinued by the manufacturer; consult system integrators for modern alternatives (1756-M3 or 1756-M12)
Works With
- Rockwell Automation Studio 5000 Logix Designer
- RSLogix 5000 (legacy programming suite)
- ControlLogix backplane communication protocol
- DeviceNet, DH+, ControlNet, and EtherNet/IP via optional communication modules
