{"product_id":"1756-m3-ab-allen-bradley-controllogix-logix5550-expansion-memory-module","title":"1756-M3 | AB Allen-Bradley | ControlLogix Logix5550 Expansion Memory Module","description":"\u003ch3\u003eProduct Summary\u003c\/h3\u003e\n\u003cp\u003eThe \u003cstrong\u003eAllen-Bradley 1756-M3\u003c\/strong\u003e is a \u003cstrong\u003e2 MB Expansion Memory Module\u003c\/strong\u003e by Rockwell Automation, designed for use with the legacy \u003cstrong\u003eLogix 5550\u003c\/strong\u003e (1756-L1) ControlLogix processor. It provides additional non-volatile memory to expand the controller's user program capacity from the base 160 KB to \u003cstrong\u003e2 MB total\u003c\/strong\u003e, enabling larger and more complex industrial automation applications on early ControlLogix platforms.\u003c\/p\u003e\n\n\u003ch3\u003eCore Specifications\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eModel Number:\u003c\/strong\u003e 1756-M3\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e ControlLogix Expansion Memory Module\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMemory Capacity:\u003c\/strong\u003e 2 MB (2 megabytes)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompatible Controllers:\u003c\/strong\u003e 1756-L1 Logix 5550 (memory range 750 KB to 32 MB)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBackplane Current:\u003c\/strong\u003e 1.20–1.25 A at 5.1 VDC; 0.014 A (14 mA) at 24 VDC\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePower Dissipation:\u003c\/strong\u003e \u0026lt;6.2 W typical\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.22 kg (7.7 oz)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Allen-Bradley by Rockwell Automation\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eElectrical \u0026amp; Functional Characteristics\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMemory Type:\u003c\/strong\u003e Non-volatile expansion memory for user program and data storage\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInstallation:\u003c\/strong\u003e Plugs into dedicated memory expansion slot on 1756-L1 processor\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBase Memory:\u003c\/strong\u003e 1756-L1 base controller includes 160 KB user memory; 1756-M3 expands to 2 MB total\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eData Retention:\u003c\/strong\u003e Battery-backed RAM with lithium battery (1756-BA1 or 1756-BA2)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eStatus Indicators:\u003c\/strong\u003e Controller status LEDs indicate memory health and battery status\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSystem Integration \u0026amp; Compatibility\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePrimary Platform:\u003c\/strong\u003e ControlLogix 1756 chassis (first generation)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompatible Processor:\u003c\/strong\u003e 1756-L1 Logix 5550 Controller\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRelated Memory Modules:\u003c\/strong\u003e\n    \u003cul\u003e\n      \u003cli\u003e1756-M1 — 512 KB expansion memory\u003c\/li\u003e\n      \u003cli\u003e1756-M2 — 1 MB expansion memory\u003c\/li\u003e\n      \u003cli\u003e1756-M3 — 2 MB expansion memory (this part)\u003c\/li\u003e\n      \u003cli\u003e1756-M1K — 512 KB conformal coated\u003c\/li\u003e\n      \u003cli\u003e1756-M2K — 1 MB conformal coated\u003c\/li\u003e\n      \u003cli\u003e1756-M3K — 2 MB conformal coated\u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRelated Processors:\u003c\/strong\u003e 1756-L1M1 (512 KB base), 1756-L1M2 (1 MB base), 1756-L1M3 (2 MB base with integrated memory)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eEnvironmental \u0026amp; Operational Limits\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOperating Temperature:\u003c\/strong\u003e 0°C to 60°C (32°F to 140°F)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eStorage Temperature:\u003c\/strong\u003e -40°C to +85°C (-40°F to 185°F)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHumidity:\u003c\/strong\u003e 5% to 95% RH, non-condensing\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eVibration:\u003c\/strong\u003e 2G, 10 to 500 Hz\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eShock:\u003c\/strong\u003e 30G operating\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eESD Immunity:\u003c\/strong\u003e 6 kV indirect contact discharge; 8 kV air discharge (IEC 61000-4-2)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eEmissions Class:\u003c\/strong\u003e Group 1, Class A\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIEC Temperature Code:\u003c\/strong\u003e T4A \/ T4\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eIndustrial Applications\u003c\/h3\u003e\n\u003cp\u003eDeployed in legacy ControlLogix systems from the late 1990s to early 2000s, primarily in manufacturing, material handling, and process control applications where expanded program memory was required for complex ladder logic, sequential function charts, and structured text programs on the original Logix 5550 platform.\u003c\/p\u003e\n\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\n\u003ch4\u003eWhat is the 1756-M3 used for?\u003c\/h4\u003e\n\u003cp\u003eIt is a \u003cstrong\u003e2 MB memory expansion module\u003c\/strong\u003e for the 1756-L1 Logix 5550 ControlLogix processor, expanding user program capacity from 160 KB base memory to 2 MB total.\u003c\/p\u003e\n\n\u003ch4\u003eWhich controllers are compatible with the 1756-M3?\u003c\/h4\u003e\n\u003cp\u003eThe 1756-M3 is designed specifically for the \u003cstrong\u003e1756-L1 Logix 5550\u003c\/strong\u003e first-generation ControlLogix controller. It is not compatible with later 1756-L6x, L7x, or L8x series controllers which have integrated memory.\u003c\/p\u003e\n\n\u003ch4\u003eWhat is the difference between 1756-M3 and 1756-M3K?\u003c\/h4\u003e\n\u003cp\u003eThe \u003cstrong\u003e1756-M3\u003c\/strong\u003e is the standard version. The \u003cstrong\u003e1756-M3K\u003c\/strong\u003e features \u003cstrong\u003econformal coating\u003c\/strong\u003e on the circuit boards for enhanced protection against moisture, dust, and corrosive gases in harsh industrial environments.\u003c\/p\u003e\n\n\u003ch4\u003eIs the 1756-M3 still supported by Rockwell Automation?\u003c\/h4\u003e\n\u003cp\u003eNo — the 1756-L1 Logix 5550 platform and its memory modules are \u003cstrong\u003elegacy\/obsolete\u003c\/strong\u003e products. Rockwell Automation no longer manufactures or supports these modules. Replacement units must be sourced from authorized surplus dealers or refurbishment services.\u003c\/p\u003e\n\n\u003ch4\u003eWhat are the related part numbers?\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e1756-M1 — 512 KB expansion memory\u003c\/li\u003e\n  \u003cli\u003e1756-M2 — 1 MB expansion memory\u003c\/li\u003e\n  \u003cli\u003e1756-M3 — 2 MB expansion memory (this part)\u003c\/li\u003e\n  \u003cli\u003e1756-M1K — 512 KB conformal coated\u003c\/li\u003e\n  \u003cli\u003e1756-M2K — 1 MB conformal coated\u003c\/li\u003e\n  \u003cli\u003e1756-M3K — 2 MB conformal coated\u003c\/li\u003e\n  \u003cli\u003e1756-L1 — Logix 5550 base processor (160 KB)\u003c\/li\u003e\n  \u003cli\u003e1756-L1M3 — Logix 5550 with integrated 2 MB memory\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Allen Bradley","offers":[{"title":"Default Title","offer_id":53684211024056,"sku":"1756-M3","price":99.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0935\/6132\/3704\/files\/1756-M3_3.png?v=1782974010","url":"https:\/\/www.globalpetroparts.com\/products\/1756-m3-ab-allen-bradley-controllogix-logix5550-expansion-memory-module","provider":"Global Petro Parts Automation","version":"1.0","type":"link"}