About

The 1764-MM3RTC MicroLogix 1500 Memory Module with a real-time clock by Allen-Bradley is a memory module for the 1500LRP MicroLogix controller which allows for program backups and confers data downloads and memory protection for safety. The 1764-MM3RTC has a 16KB maximum memory size and the real-time clock (RTC) provides Year, Month, Week, Day, Hour, Minute, and Second information to the function file in the 1500LRP MicroLogix controller. The real-time clock has a temperature-dependent accuracy of +34 to -70 seconds/month at 0°C (32°F), through -133 to -237 seconds/month accuracy at 55°C (131°F).  The real-time clock has an internal battery which provides backups for stored time-stamped data, and its battery has a 5-year minimum lifespan when used at a temperature range of 0-40°C (32-104°F). The 1764-MM3RTC can only store 1 user program at a time, and it is capable of providing application memory security because it prevents the controller from execution if the program on the memory module does not match the one on the controller. The 1764-MM3RTC also supports a “read many” and “write once” function, and it is designed to remain undamaged if it is removed at any time from the controller. It has an operating temperature range of 0-55°C (32-131°F), at 5-95% non-condensing relative humidity, and it is built for storage at a temperature range of -40-85°C (-40-185°F).