## Feature #1285

Updated by tin over 6 years ago

**Computation of the drift rate of calibration constant 72 (will take 1 week to complete): C = [(A – B) * 1000000] / [A * D] ppm per day A = the value of the calibration constant 72 (following an ACAL on day 1 of the test) B = the value of calibration constant 72 (following an ACAL on the last day of the test) C = the drift rate of calibration constant 72 in ppm per day D = the number of test days where the instrument was powered on during the test interval (See Note # 1) If the absolute value of C is > 0.43 ppm per day, then the A3 assembly in your instrument needs to be replaced. *Complete an ACAL just prior to obtaining the present value of Calibration Constant 72* |Date |CAL 72 after ACAL|ppm Deviation| |11/16| | Initial | |11/17| | Initial | |11/18| | Initial | |11/19| | Initial | |11/20| | Initial | |11/21| | Initial | |11/22| | Initial | |11/23| | Initial | |11/24| | Initial | |11/25| | Initial | |11/26| | Initial |