The Computrac® MAX® 500, 1000, and 2000 series instruments and the CT-3000 have internal batteries that maintain power to the memory during times the instruments are switched off, or in the case of a mains power failure. ...
These instruments should not be left unplugged for weeks at a time, since the batteries could run down, resulting in the loss of stored calibration parameters and memory start information. These batteries are replaced by the factory when the instruments are sent in for annual calibration.