FB_PMA_Protection

The FB_PMA_Protection function block is used to monitor network data or results using thresholds and hysteresis. Any number of input channels can be monitored simultaneously. An additional output summarizes whether at least one threshold value has been exceeded or not reached.

Syntax

Definition:

FUNCTION BLOCK FB_PMA_Protection
VAR_INPUT
    stInitPars        : ST_PMA_Protection_InitPars;
END_VAR
VAR_OUTPUT
    bError            : BOOL;
    ipResultMessage   : I_TcMessage;
    bNewResult        : BOOL;
    bProtectionResult : BOOL;
    tLastEvent        : ULINT;
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 possible by calling the Init method again.

Name	Type	Description
stInitPars	ST_PMA_Protection_InitPars	Function-block-specific structure with initialization parameters

Outputs

Name	Type	Description
bError	BOOL	TRUE if an error occurs.
ipResultMessage	I_TcMessage	The interface offers detailed information about the return value.
bNewResult	BOOL	TRUE once new results have been calculated.
bProtectionResult	BOOL	TRUE as soon as an input channel is outside the threshold values.
tLastEvent	ULINT	Timestamp at which the bProtectionResult output last changed.

Methods

Methods can be used to scale different systems (single-phase or three-phase) and different resolutions (16 bits or 32 bits).

Name	Description
Call	The method is called to perform the calculation.
Init	Alternative to the function block initialization
Reconfigure	The method is called to reconfigure the function block at runtime.
Reset	The current calculations are reset with the method.
SetChannelValue	Method for transferring values to the algorithm.

Example

VAR CONSTANT
    cInitPars: ST_PMA_Protection_InitPars :=
    (
        nNumChannels := 3,
        fSetpoint := 230.0,
        fMinThreshold := 0.9,
        fMinThresholdHysteresis := 0.01,
        fMaxThreshold := 1.1,
        fMaxThresholdHysteresis := 0.01
    );
END_VAR
VAR
    fbProtection : FB_PMA_Protection := (stInitPars:= cInitPars);
    tTimestamp : ULINT;
    fVoltage_FeedIn : LREAL;
    fVoltage_Conumer1 : LREAL;
    fVoltage_Conumer2 : LREAL;
    aOut : ARRAY[1..3] OF BOOL
END_VAR

// Get current dc time - Tc2_EtherCAT lib has to be included
tTimestamp := Tc2_EtherCAT.F_GetActualDcTime64();

// Call algorithm
fbProtection.SetChannelValue(1, fVoltage_FeedIn);
fbProtection.SetChannelValue(2, fVoltage_Conumer1);
fbProtection.SetChannelValue(3, fVoltage_Conumer2);
fbProtection.Call(tTimestamp, ADR(aOut), SIZEOF(aOut));

Requirements

Development environment	Target platform	PLC libraries to include
TwinCAT v3.1.4024.0	PC or CX (x86, x64)	Tc3_PowerMonitoring

Further Information