An intelligent electronic device with constant calibration capabilities for high accuracy measurements and method thereof are provided. The intelligent electronic device presented herein constantly samples the output of at least one signal from a sensor and at least three reference signals, where the reference signals include a high reference signal, a low reference signal, and a medium reference signal. Using the constant calibration implementations provided, the intelligent electronic device can calibrate and compensate a signal from a sensor in real time. The constant calibration implementations provided are independent of time and temperature, and are advantageous in a rapidly changing environment. Furthermore, the constant calibration implementations provided enable the intelligent electronic device to track changes in an applied correction factor for traceability in the error correction process. The intelligent electronic device can determine, when the correction factor is applied, how often, and temporary drifts in accuracy.