Product Overview
Program loss on a running line is a maintenance engineer’s worst nightmare. The Allen-Bradley 1766-MM1 is a 384 KB memory module built for the MicroLogix 1400 controller family. It plugs directly into the controller’s dedicated memory module slot and holds user programs and data as a separate backup. When a fault, surge, or operator error wipes the processor, this module lets you restore quickly instead of rebuilding logic from scratch.
Technical Specifications
384 KB of Dedicated Backup Memory
The 1766-MM1 provides 384 Kbytes of user memory. This is not an expansion of the controller’s integrated memory; it is a separately allocated store. That distinction matters on the plant floor: your running program stays untouched while a verified copy sits in the module.
Write Protection and Program Compare
The module supports data file and memory module write protection, plus program comparison. You can lock the backup against accidental edits and confirm that the stored logic matches what the controller is running.
Automatic Loading and Status Bits
With bit S:1/11 set to “Load Memory Module Always,” the controller loads from the module automatically. Status bits S:1/10, S:1/11, and S:1/12 report module state, so your ladder logic can flag a missing or mismatched module before it becomes a downtime event.
Removal and Insertion Under Power
The 1766-MM1 can be removed or inserted while the controller is powered. The module is recognized after the next power cycle, which simplifies spare swaps during planned maintenance windows.
Compatibility with MicroLogix 1400 Controllers
The module is designed for the MicroLogix 1400 series and fits these controllers: 1766-L32AWA, 1766-L32AWAA, 1766-L32BWA, 1766-L32BWAA, 1766-L32BXB, and 1766-L32BXBA. Each of these ships with the memory module port and cover in place, so installation is a direct plug-in with no adapters.
Practical Applications
Press and Safety-Critical Control
The module supports special safety and security functions for press control and other critical applications. A stored, write-protected program gives you a known-good reference after any fault.
Program Transport Between Machines
Because the module stores programs for use with other controllers, it doubles as a transfer medium. Commission a second MicroLogix 1400 by moving the module rather than re-entering logic.
Auto-Recovery After a Fault
After a controller fault, the module enables auto-recovery through a power cycle. For remote pump stations or unmanned skids, that means fewer site visits and faster restart.
Installation and Maintenance Notes
Insert the module into the memory module slot and secure the cover. Configure loading through the controller screen following system prompts. Operating temperature is 0 to 55 deg.C, so keep panel ventilation within that range. During routine inspections, check that the module is seated and that status bits report correctly. For replacement and upgrade planning, contact Oil AutoTech for hands-on technical selection help and ready-to-ship spares.
Please verify current lifecycle status and availability with Oil AutoTech before ordering.
