The Power Analyzer Accuracy and Basic Uncertainty Calculator from Yokogawa Test&Measurement helps users determine the uncertainty in voltage, current, and active power (watts) measurement values for various frequency ranges and wiring systems. Download the Uncertainity Calculator then select the appropriate sheet that matches the instrument you are using. From there enter the fields highlighted in yellow (voltage and current reading and ranges, frequency and power factor) and the calculator displays the uncertainty values in the subsequent tables.
The Power Analyzer Accuracy and Basic Uncertainty Calculator also applies to external current sensors. The EX mV input must be converted to Amps. For example, with 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. Enter the reading value and the high accuracy calculator displays the uncertainty at the input terminals. Please note this does not include the error of the EX device.