Allen-Bradley 1766-MM1 Memory Module

1766-MM1 MicroLogix 1400 Memory Expansion

Product Introduction

The 1766-MM1 memory module is a practical accessory for the Allen‑Bradley MicroLogix 1400 programmable controller series. It does not increase the processor’s built‑in RAM but instead supplies a separate 384 KB storage space. This space stores user programs and data files safely. You can use it to back up critical logic, move programs between compatible controllers, or enable automatic system recovery after a fault.

Many industrial facilities choose this module because it adds a layer of protection against data loss. Voltage fluctuations, operator errors, or unexpected controller halts can corrupt internal memory. The 1766-MM1 holds a clean copy of your application, so you can restore operations quickly. Additionally, its write‑protection feature prevents accidental overwrites, and the program‑compare function verifies that the loaded logic matches the stored version.

Key Technical Specifications

• User Memory: 384 Kbytes (separate from the controller’s built‑in memory)

• Supported Controllers: 1766-L32AWA, 1766-L32AWAA, 1766-L32BWA, 1766-L32BWAA, 1766-L32BXB, and 1766-L32BXBA

• Mounting Location: Directly inserts into the dedicated memory module slot on the MicroLogix 1400 CPU

• Automatic Loading Support: Yes, controlled via bit S:1/11 (“Load Memory Module Always”)

• Status Indicators: Bits S:1/10, S:1/11, and S:1/12 report module presence and load status

• Operating Temperature: 0 to 55 °C (32 to 131 °F)

The module supports removal and insertion while the controller remains powered. However, the system only recognizes the module after the next power cycle. This hot‑swap capability reduces downtime during maintenance. Moreover, the 1766-MM1 uses a simple plug‑in design, so no additional cabling or mounting hardware is required.

Functional Features for Critical Applications

This memory module offers several functions that go beyond simple storage. First, it allows program comparison between the module and the controller. This ensures that the running logic matches the backup, which is essential for press controls and other safety‑related processes.

Next, the 1766-MM1 provides data file protection and write protection for the memory module itself. These security measures prevent unauthorized or accidental changes. Furthermore, if a controller fault occurs, the module supports auto‑recovery through a power cycle. After restarting, the controller can automatically reload the program from the module, minimizing production interruptions.

In addition, you can use this module to transport programs from one MicroLogix 1400 to another. Simply save the application to the 1766-MM1, remove it, and insert it into a different compatible controller. This approach simplifies machine upgrades and fleet‑wide updates.

Installation and Configuration Guide

Installing the 1766-MM1 is straightforward. Follow these steps:

1. Power down the MicroLogix 1400 controller (optional but recommended).

2. Locate the memory module port on the front of the CPU. Remove the protective cover.

3. Align the module with the slot and press it firmly until it seats completely.

4. Reapply power to the controller.

For automatic loading, configure bit S:1/11 to “1” using your programming software. This setting forces the controller to load from the 1766-MM1 on every power‑up. If you prefer manual control, leave the bit at “0” and use the operator screen or RSLogix 500 to initiate the load.

Remember that if you insert or remove the module under power, you must cycle the power for the controller to recognize the change. Also, always verify that the module is fully inserted to avoid intermittent connections.

Environmental and Mechanical Data

• Operating Temperature: 0 to 55 °C

• Storage Temperature: -40 to 85 °C

• Relative Humidity: 5 to 95% (non‑condensing)

• Shock: 30 g peak acceleration, 11 ms duration

• Vibration: 5 g at 10 to 500 Hz

These ratings make the 1766-MM1 suitable for factory floors and harsh industrial environments. Its compact size and low weight do not add significant bulk to the control panel.

Packaging List

• 1 × Allen‑Bradley 1766-MM1 Memory Module

• 1 × Protective dust cover (pre‑installed on the module)

• 1 × Quick installation leaflet

Note: Cables, programming software, and mounting screws are not included.

Shipping Information

We ship all orders via FedEx, UPS, or DHL with full tracking. Each module is individually packed in anti‑static material to prevent ESD damage during transit.

Frequently Asked Questions (FAQ)

Q1: Does the 1766-MM1 increase the built‑in memory of the MicroLogix 1400?
No. The 1766-MM1 adds a separate 384 KB storage area for backups and transfers. It does not expand the processor’s working RAM.

Q2: Can I hot‑swap the module while the controller is running?
Yes, you can insert or remove it under power. However, the controller will only detect the module after a subsequent power cycle.

Q3: Which controllers work with this memory module?
This module supports the 1766-L32AWA, 1766-L32AWAA, 1766-L32BWA, 1766-L32BWAA, 1766-L32BXB, and 1766-L32BXBA models.

Q4: How do I enable automatic program loading?
Set bit S:1/11 to “1” in your RSLogix 500 program. This configures the controller to load from the 1766-MM1 on every power‑up.

Q5: What happens if the module fails during operation?
If a fault occurs, the controller can auto‑recover from the 1766-MM1 during the next power cycle, provided the module contains a valid program and the load bit is enabled.