These powerful devices guarantee uninterrupted operation through a backup capable microcontroller which supports real-time clock (RTC) operation and power management from the main as well as from up to two separate auxiliary supplies. Real-time clock and calendar modes are password protected and operate from a separate voltage supply with a programmable charger for accurate data logging and measurements with no loss of data. By default, the system operates from the primary supply. In case of power loss, however, automatic or manual switching to the auxiliary power supply is facilitated. This switch is done while maintaining full functionality, assuring that there will be no data loss. The backup supply can either be a battery for larger power outages or a capacitor for shorter durations. Automatic threshold based monitoring of primary and auxiliary power supplies provides a second layer of assurance against data loss.