The Power Analyzer Accuracy and Basic Uncertainty Calculator can be used to determine the uncertainty in voltage, current, and active power (watts) measurement values for various frequency ranges and wiring systems. To use the calculator please download the Excel spreadsheet and select the appropriate sheet that matches the instrument you are using. Simply enter the fields highlighted in yellow (Voltage & Current Reading and Ranges, Frequency and Power Factor) and the calculator will display the uncertainty values in the subsequent tables.
The Power Analyzer calculator also applies to external current sensors. The EX mV input must be converted to Amps. For example, if you had a 500A DC Shunt or CT, slide the spreadsheet to the right, where the lookup table is located. At the bottom of the current table is a blank field. Enter the value for the Full Scale Range of the external device, 500 in this example. Then enter the reading value and the calculator will display the uncertainty at the input terminals. Keep in mind that it does not include the error of the EX device.