FB_PMA_BasicValues_Period_1Ph

The function block FB_PMA_BasicValues_Period_1Ph calculates analysis values for the signal sequence of current and voltage in a single-phase system. These include the mean value, the RMS value, the peak value, the rectified value, the crest factor and the form factor for current and voltage. The results refer to a configurable number of signal periods. The period duration refers to the frequency specified at the start of the period at the input of the Call method. The statistical results refer to the entire runtime or the time at which the statistical results were last reset.

The input buffer is provided via the function block FB_PMA_Source_1Ph. This can include one or more signal periods or individual fragments of oversampling arrays.

Syntax

Definition:

FUNCTION BLOCK FB_PMA_BasicValues_Period_1Ph
VAR_INPUT
    nOwnID                : UDINT;
    tTransferTimeout      : LTIME := LTIME#500US;
    stInitPars            : ST_PMA_BasicValues_Period_InitPars;
END_VAR
VAR_OUTPUT
    bError              : BOOL; 
    ipResultMessage     : I_TcMessage;
    bNewResult          : BOOL;
    nCntResults         : ULINT;
    fMeanValue_U        : LREAL;
    fRMS_U              : LREAL;
    fRMS_U_Min          : LREAL;
    fRMS_U_Max          : LREAL;
    fPeakValue_U        : LREAL;
    fPeakHold_U         : LREAL;
    fRectifiedValue_U   : LREAL;
    fCrestFactor_U      : LREAL;
    fFormFactor_U       : LREAL;
    fMeanValue_I        : LREAL,
    fRMS_I              : LREAL,
    fRMS_I_Min          : LREAL,
    fRMS_I_Max          : LREAL,
    fPeakValue_I        : LREAL,
    fPeakHold_I         : LREAL;
    fRectifiedValue_I   : LREAL;
    fCrestFactor_I      : LREAL;
    fFormFactor_I       : LREAL;
    bValidStatistics    : BOOL;
END_VAR

Inputs

The input parameters of this function block represent initialization parameters and must be assigned when declaring the function block instance (alternative: Init method). They may only be assigned once. A change at runtime is not possible.

Outputs

Methods

Sample

VAR CONSTANT
    cOversamples : UDINT := 10;
    cSourceInitPars: ST_PMA_Source_InitPars := (
        nBufferLength := cOversamples);
    cFrequencyInitPars : ST_PMA_Frequency_Period_InitPars := (
        nBufferLength := cOversamples,
        fSampleRate := cOversamples * 1000,
        fMinFreq := 45.0,
        fMaxFreq := 55.0,
        nPeriods := 1,
        nFilterOrder := 2,
        fCutOff := 70.0,
        eInputSelect := E_PMA_InputSelect.Voltage,
        fMinInput := 200.0);
    cBasicValuesInitPars : ST_PMA_BasicValues_Period_InitPars := (
        nBufferLength := cOversamples,
        fSampleRate := cOversamples * 1000,
        fMinInputCurrent := 0.01,
        nPeriods := 1);
END_VAR
VAR
    aVoltage AT%I* : ARRAY[1..cOversamples] OF LREAL;
    aCurrent AT%I* : ARRAY[1..cOversamples] OF LREAL;
    fbSource : FB_PMA_Source_1Ph := (nOwnID := 1, aDestIDs := [2,3], stInitPars := cSourceInitPars);
    fbFrequency : FB_PMA_Frequency_Period_1Ph := (nOwnID := 2, stInitPars := cFrequencyInitPars);
    fbBasicValues : FB_PMA_BasicValues_Period_1Ph := (nOwnID := 3, stInitPars := cBasicValuesInitPars);
END_VAR

// Call source
fbSource.Call(ADR(aVoltage), ADR(aCurrent), SIZEOF(aVoltage), 0);

// Call algorithms
fbFrequency.Call(FALSE);
fbBasicValues.Call(fbFrequency.fFreq, FALSE);

Requirements