Allen-Bradley 1764-RTC

The 1764-RTC real-time clock (RTC) module is manufactured by Allen Bradley/Rockwell Automation as part of the MicroLogix 1500 product line. This RTC module features a real-time clock which is used by the controllers in the MicroLogix 1500 series. The output source for this RTC module is a DC FET and relay port and has a memory capacity of 7 kilobytes, with 3.56 kilobytes specifically for the user program and 4 kilobytes dedicated for user data, when it is installed on 1764-LSP, it has 14 kilobytes with 10 kilobytes dedicated for the user program while 4 kilobytes for the user data. The 1764-RTC RTC module has a NEMA IP20 enclosure rating. For its battery to last, always ensure the storage temperature of this real-time module is between -40 to 40 degrees Celsius because higher temperatures can shorten battery life which us about 5 years under normal conditions. Allen Bradley 1764-RTC module comes with two-piece design consisting of a base unit and processor which can be independently replaced, and they can slide together and takes up only a minimal footprint. The module is designed for use for establishing a time-base for the MicroLogix 1500 controller which requires coordination with instantaneous events. The clock shows date and time. The operator can either install or remove Allen Bradley 1764-RTC module while the controller is in operation without any interference. Nonetheless, the RTC module may not be immediately recognized, but will only be recognized when it enters into a non-executing mode, fault condition, or program mode and after a power cycle.

An Allen Bradley product, the 1764-RTC is a real-time clock module and is classified as an accessory for the MicroLogix 1500 product line. This real-time clock (RTC) has the function to provide time data that includes the year, month, day, hour, minute, and second. This real-time clock also provides day of the week. This information is provided to the RTC function file that exists within the controller. This real time clock module is installed inside the processor and is seen just under the processor cover. This RTC and the memory module both have the ability to be inserted or removed even when powered. Doing this would not cause damage to the RTC, nor to the processor module. Additionally, if the module is installed while the ML1200 or ML1500 is executing, the module is not initialized and recognized until there is an occurrence of a power cycle or the controller is faulty or in programming mode. An internal battery is located within the real-time clock. This battery is not replaceable. The RTC has a function file, and it features indicators, one of which is a battery low indicator bit that shows the status of the RTC battery. The indicator bit is high when the battery is low, and the indicator bit is low when the battery has enough charge. The low indicator means that in less than 14 days, the battery will die. Additionally, this shows that the RTC needs to be replaced. If the RTC is not attached, the indicator bit is clear.