The expansion memory module that is known as the 1756-M2 memory module is used for various applications within harsh industrial environments. The unit is part of the ControlLogix 1756 product series introduced by Allen-Bradley/Rockwell Automation. The ControlLogix system can be constructed from a variety of high-performance components like processors, controllers, memory boards, and different analog and digital modules. The ControlLogix modules are mounted in the chassis and they communicate through the ControlNet and EtherNet/IP networks. The available ControlLogix controllers have data and logic memory capacities from 750 kilobytes to 32 megabytes and they feature a backplane currents of 1.20 to 1.25 Amps at 5.1 Volts DC.

The 1756-M2 expansion memory module comes with 1 megabyte of memory capacity and an open-style enclosure. According to specifications provided by Allen-Bradley, the unit has an operating temperature range of 0 to 60 degrees Celsius (32 to 140 degrees Fahrenheit) and storage temperature of -40 to 85 degrees Celsius (-40 to 185 degrees Fahrenheit). In addition to that, the 1756-M2 module has a moderate tolerance to vibration (2 G at 10 to 500 Hertz frequency) and shock (30 G), and it operates in environments with relative humidity rating of up to 95% (non-condensing). The 1756-M2 module supports emission class A (Group 1) and it has a temperature code rating of T4A/T4. The unit is designed to meet the requirements set by standards like the UL, CE, CSA, and C-Tick standards. The ESD immunity of the 1756-M2 unit per the IEC 61000-4-3 standards is 6 kiloVolts for indirect contact discharge and 8 kiloVolts for air discharge.