OVERVIEW

Official designation: Allen-Bradley 1756-M3 (ControlLogix, Expansion Memory Module)

Role/Application: Increases user memory capacity for legacy ControlLogix controllers to support larger data tables and complex logic execution.

KEY SPECS SUMMARY

Power: Controller powered

Interfaces / Ports: Internal module pin

Indicators: N/A

Operating Temp: 0 to 60 degrees C

Platform / Compatibility: ControlLogix 5555

Limit: 2 MB User Memory

Lifecycle: Discontinued

FREQUENTLY ASKED QUESTIONS

Technical Specifications:

Q: What is the specific memory capacity added by the 1756-M3?

A: This module adds 2 Megabytes of SRAM to the controller.

Wiring & Installation:

Q: Does the 1756-M3 require external wiring or terminal blocks?

A: No, it installs directly onto the controller circuit board.

Troubleshooting & Compatibility:

Q: Which controllers are compatible with this memory expansion?

A: It is designed exclusively for the 1756-L55 series.

Replacement & Upgrades:

Q: What is the recommended upgrade path for this discontinued module?

A: Transition to 1756-L7 or L8 controllers with built-in memory.