INSTRUMENT MAINTENANCE
PRACTICAL TASK P2. BALANCE CALIBRATION Outline This procedure checks the accuracy of a properly maintained balance by the use of standard masses. The masses used and the acceptable limits depend on the type of balance used (top pan/analytical) and the number of decimals places allowed (2‐4). Procedure This must be done for the balance you have been assigned for Task P1. 1. Obtain a set of calibration weights. 2. Check that the balance is clean and level. 3. Close all doors and switch on (if necessary). 4. Tare the balance. 5. Measure the weight of the standard masses specified in Table 1 below. You must use the supplied tweezers to handle the standard masses. TABLE 1. Masses to be used depending on balances Balance type Analytical 4‐place Top pan 2 & 3‐place Masses to be used 100 mg, 1 g, 10 g 1 g, 10 g, 100 g Reporting Requirements Use the standard Performance Check reporting sheet. Table 2 provides the acceptable tolerances. TABLE 2. Accepted tolerances Standard masses 4‐place 3‐place 2‐place 100 mg 0.0005 g na na 1 g 0.0005 g 0.001 g 0.01 g 10 g 0.001 g 0.002 g 0.02 g 100 g na 0.005 g 0.05 g This is a compulsory task.