Analytical Balance

Analytical balances are precision weighing instruments designed for the highest accuracy in laboratory applications. They use electromagnetic force compensation (a servo-controlled electromagnet that balances the load) to achieve resolutions of 0.1 mg or finer. Analytical balances typically include a draft shield enclosure to protect against air currents, and must be placed on vibration-free, level surfaces for reliable operation.

Calibration of analytical balances involves testing with calibrated reference weights at multiple points across the range. Key parameters include corner load errors (eccentric loading), repeatability, linearity, and the accuracy of internal calibration weights (if equipped). Reference weights must be OIML Class E1 or E2 to provide sufficient accuracy for calibrating analytical balances. Calibration also includes verification of the level indicator, draft shield integrity, and environmental conditions (temperature, humidity, air currents, vibration).

In calibration management, analytical balances require particular attention to environmental conditions and user technique. Temperature fluctuations, air currents, static electricity, and vibration can all cause measurement errors larger than the balance's resolution. Many modern analytical balances include internal motorized calibration weights and can perform automatic calibration when temperature changes are detected. However, these internal calibrations must be verified periodically using external traceable reference weights. Calibration intervals are typically 6-12 months, with daily or weekly verification using check weights as an essential practice.