Allen-Bradley 1764-MM2RTC MicroLogix 1500 Memory Module with Real-Time Clock

Product Overview

The 1764-MM2RTC provides critical data redundancy and time-stamping capabilities for the MicroLogix 1500 controller platform. This dual-function expansion module integrates 16 KB of non-volatile memory for program backup alongside a high-precision Real-Time Clock (RTC). It ensures the controller retains vital ladder logic and register data during power cycles while enabling time-scheduled automation events. Although the manufacturer has discontinued this series, we supply this unit as 100% Brand New original hardware, allowing you to maintain existing MicroLogix installations without upgrading the entire control architecture.

Technical Specifications

The 1764-MM2RTC combines memory storage and chronological tracking in a compact form factor:

Engineering Advantages

• Non-Volatile Program Security: The 16 KB flash memory stores a complete backup of the user program and data table. This prevents catastrophic data loss if the controller's internal battery fails, allowing for immediate automatic recovery upon power-up.

• Precision Time-Stamping: The integrated Real-Time Clock enables the PLC to execute time-of-day, day-of-week, or calendar-based control logic. This functionality proves essential for data logging applications where every event requires an accurate temporal marker.

• Eliminates Manual Program Loading: By setting the controller to "Load on Power-up," the 1764-MM2RTC automatically transfers the stored program to the processor's RAM. This feature minimizes downtime in remote locations where a technician with a laptop may not be immediately available.

• Compact Plug-in Design: The module seats directly into the specialized memory port on the front of the MicroLogix 1500 processor. Its low-profile architecture ensures it does not interfere with the controller's wiring or physical footprint within the enclosure.

• Bumpless Maintenance: The module allows for easy "cloning" of PLC programs. You can program one module and physically move it to another MicroLogix 1500 unit to replicate control parameters quickly across multiple machines.

Installation Guidelines

1. Power Down: Always remove power from the MicroLogix 1500 base unit before inserting or removing the 1764-MM2RTC to prevent electrical transients from damaging the flash memory.

2. Alignment: Remove the protective cover from the memory module port on the processor. Align the module pins carefully with the port and press firmly until it seats flush.

3. Software Configuration: Use RSLogix 500 software to configure the "Memory Module" settings in the Controller Properties. You must define whether the processor should load from the module on every power cycle or only upon memory error.

4. Clock Sync: Use the "Set Date and Time" function in the programming software to synchronize the RTC with your local time zone after the initial installation.

FAQs

Q: Can I use the 1764-MM2RTC in a MicroLogix 1100 or 1200 controller?

A: No. The 1764-MM2RTC specifically fits the 1764-series processor used in the MicroLogix 1500 system. Other MicroLogix models utilize different memory module form factors (such as the 1762 or 1763 series).

Q: Does this module require a battery to maintain the 16 KB memory?

A: No. The 16 KB memory uses non-volatile flash technology, which retains data indefinitely without power. However, the Real-Time Clock function relies on the controller's internal battery to keep time while the system is powered off.

Q: What is the difference between the 1764-MM1 and the 1764-MM2RTC?

A: The 1764-MM1 provides memory backup only. The 1764-MM2RTC adds the Real-Time Clock feature, which is necessary if your ladder logic includes RTC-based instructions like "Read Clock" or "Write Clock."

Q: Is it possible to write-protect the program on the memory module?

A: Yes. You can configure write-protection via the RSLogix 500 software settings to prevent unauthorized or accidental overwriting of the backup program stored on the 1764-MM2RTC.