Calibration Command

The configuration command (CAL) is used to automatically calibrate the board. It requires accurate and stable voltage and current sources and loads, which can be provided by a meter test bench, such as the WECO (or equivalent equipment). Refer to the Calibrate the Demo Board Using the Demo Meter Application for additional information.

This command must be sent after a configuration command, to ensure that the proper configuration was applied.

There are six variants of the calibration command:

  • CAL_A to calibrate the phase A individually.
  • CAL_B to calibrate the phase B individually.
  • CAL_C to calibrate the phase C individually.
  • CAL_N to calibrate Neutral line individually.
  • CAL_T to calibrate the three phases simultaneously.
  • CAL_TN to calibrate the three phases and Neutral simultaneously.

The configuration command has the following parameters:

  • The CAL_A, CAL_B, and CAL_C commands:
    • Ua (for CAL_A), Ub (for CAL_B), Uc (for CAL_C): Rms voltage applied to the voltage input. Units: Volts.
    • Ia (for CAL_A), Ib (for CAL_B), Ic (for CAL_C): Rms current applied to the current input. Units: Amps.
    • Aa (for CAL_A), Ab (for CAL_B), Ac (for CAL_C): Angle between the voltage and current vectors. Units: Degrees. The value is positive if the current is lagging the voltage.
  • The CAL_N command:
    • In: Rms current applied to the Neutral current input. Units: Amps.
    • An: Angle between the voltage on dominant phase and Neutral current vectors. Units: Degrees. The value is positive if the current is lagging the voltage.
  • The CAL_T command:
    • Ua: Rms voltage applied to the voltage input (phase A). Units: Volts.
    • Ub: Rms voltage applied to the voltage input (phase B). Units: Volts.
    • Uc: Rms voltage applied to the voltage input (phase C). Units: Volts.
    • Ia: Rms current applied to the current input (phase A). Units: Amps.
    • Ib: Rms current applied to the current input (phase B). Units: Amps.
    • Ic: Rms current applied to the current input (phase C). Units: Amps.
    • Aa: Angle between the voltage and current vectors (phase A). Units: Degrees. The value is positive if the current is lagging the voltage.
    • Ab: Angle between the voltage and current vectors (phase B). Units: Degrees. The value is positive if the current is lagging the voltage.
    • Ac: Angle between the voltage and current vectors (phase C). Units: Degrees. The value is positive if the current is lagging the voltage.
  • The CAL_TN command:
    • Ua: Rms voltage applied to the voltage input (phase A). Units: Volts.
    • Ub: Rms voltage applied to the voltage input (phase B). Units: Volts.
    • Uc: Rms voltage applied to the voltage input (phase C). Units: Volts.
    • Ia: Rms current applied to the current input (phase A). Units: Amps.
    • Ib: Rms current applied to the current input (phase B). Units: Amps.
    • Ic: Rms current applied to the current input (phase C). Units: Amps.
    • In: Rms current applied to the Neutral current input. Units: Amps.
    • Aa: Angle between the voltage and current vectors (phase A). Units: Degrees. The value is positive if the current is lagging the voltage.
    • Ab: Angle between the voltage and current vectors (phase B). Units: Degrees. The value is positive if the current is lagging the voltage.
    • Ac: Angle between the voltage and current vectors (phase C). Units: Degrees. The value is positive if the current is lagging the voltage.
    • An: Angle between the voltage on dominant phase and Neutral current vectors. Units: Degrees. The value is positive if the current is lagging the voltage

The maximum resolution available is 0.001V (voltages), 0.0001A (currents), 0.001º (angles) and 0.01 Hz (frequency).

Examples:

  • Calibrate phase A, applying 220.00V, 5.000A, angle = 60.00º: “CAL_A (Ua = 220.00, Ia = 5.000, Aa = 60.00)”.
  • Calibrate phase B, applying 230.00V, 10.000A, angle = 60.00º: “CAL_B (Ub = 230.00, Ib = 5.000, Aa = 60.00)”.
  • Calibrate phase C, applying 120.00V, 1.000A, angle = 60.00º: “CAL_C (Uc = 120.00, Ic = 1.000, Aa = 60.00)”.
  • Calibrate Neutral line, applying 1.000A, angle = 60.00º with dominant phase: “CAL_N (In = 1.000, An = 60.00)”.
  • Calibrate a three phases system, applying to all phases 220.00V, 5.000A and a phase shift of 60.00º: “CAL_T (Ua = 220.00, Ia = 5.000,Aa = 60.00, Ub = 220.00, Ib = 5.000, Ab = 60.00, Uc = 220.00, Ic = 5.000, Ac = 60.00)”.
  • Calibrate a three phases system, including Neutral line, applying to all phases 220.00V, 5.000A and a phase shift of 60.00º: “CAL_T (Ua = 220.00, Ia = 5.000,Aa = 60.00, Ub = 220.00, Ib = 5.000, Ab = 60.00, Uc = 220.00, Ic = 5.000, Ac = 60.00, In = 5.000, An = 60.00)”.