PDAHow often should the calibration of the Pile Driving Analyzer (PDA) be checked?
American Society for Testing and Materials (ASTM) D4945 requires that an internal calibration check be performed at least once for each test day. Therefore, it is recommended that a Calibration Test (CT) signal be recorded at the beginning of each test (or at least once a day). This CT Signal can later be replayed with the calibration settings specified in Question Q1007, and the values of VMX and MEX checked as described in that Question. It will then be possible to confirm that the internal calibration of the PDA was correct when the test was done.If frequent calibration checks are made as described above (or with a Calibration Box in case Piezoresistive (PR) accelerometers are used), there should be no need for further calibration of the PDA, unless the measured data is questionable (such as if there is consistently bad proportionality between force and velocity times impedance at early impact times). Pile Dynamics recommends that the PDA be sent for recalibration at least once ever
