OVERVIEW

Official designation: Allen-Bradley 1764-MM1RTC (MicroLogix 1500, Memory Module with Real-Time Clock)

Role/Application: Combination accessory module providing 8KB EEPROM non-volatile memory for user program storage and backup, plus an integrated Real-Time Clock for precise timekeeping in MicroLogix 1500 systems.

KEY SPECS SUMMARY

Power: Internal non-replaceable battery for RTC

Interfaces / Ports: Memory module slot (internal)

Indicators: RTC battery low status (RTC:0/BL)

Operating Temp: 0 to 55 degrees C

Platform / Compatibility: 1764-LSP and 1764-LRP processors

Limit: 8 Kbytes user program and data

Lifecycle: Discontinued/Obsolete

FREQUENTLY ASKED QUESTIONS

Technical Specifications:

Q: What is the rated battery life for the internal real-time clock?

A: The non-replaceable RTC battery has an expected lifespan of 5 years at 0 to 40 degrees C.

Wiring & Installation:

Q: Can the 1764-MM1RTC module be removed from the controller while power is on?

A: Yes, the module supports removal and insertion under power without damaging the unit or controller.

Troubleshooting & Compatibility:

Q: What happens if the RTC battery voltage drops below its minimum operating threshold?

A: The RTC battery low status bit RTC:0/BL is set, signaling potential time loss within 14 days.

Replacement & Upgrades:

Q: What are the higher memory capacity options available in the MicroLogix 1500 memory module line?

A: The 1764-MM2RTC module is available, offering a larger 16KB memory capacity with the same RTC feature.