FB_VN_ReadCalibrationResult

Syntax

Definition:

FUNCTION_BLOCK FB_VN_ReadCalibrationResult
VAR_INPUT
    sFilePath               : STRING;
    aCameraMatrix           : Reference To  TcVnMatrix3x3_LREAL;
    aDistortionCoefficients : Reference To  TcVnArray8_LREAL;
    aRotationMatrix         : Reference To  TcVnMatrix3x3_LREAL;
    aTranslationVector      : Reference To  TcVnVector3_LREAL;
    bRead                   : BOOL;
    nTimeout                : TIME;
END_VAR
VAR_OUTPUT
    bBusy                   : BOOL;
    bError                  : BOOL;
    nErrorId                : UDINT;
END_VAR

Inputs

Name	Type	Default	Description
sFilePath	STRING		Full path of the file or relative path to the default directory on the target pc
aCameraMatrix	Reference To TcVnMatrix3x3_LREAL		Returns the camera matrix
aDistortionCoefficients	Reference To TcVnArray8_LREAL		Returns the distortion coefficients
aRotationMatrix	Reference To TcVnMatrix3x3_LREAL		Returns the rotation matrix
aTranslationVector	Reference To TcVnVector3_LREAL		Returns the translation vector
bRead	BOOL		Reading the file is triggered by a rising edge at this input.
nTimeout	TIME	VISION_ADS_TIMEOUT	Indicates the time before the function is cancelled.

Outputs

Name	Type	Description
bBusy	BOOL	This output remains TRUE until the function block has executed a command, but at the longest for the duration supplied to the 'nTimeout' input. While bBusy = TRUE, no new command will be accepted at the inputs.
bError	BOOL	This output is switched to TRUE as soon as an error occurs during the execution of a command. The command-specific error code is contained in ‘nErrorId’. If the function block has a timeout error, 'bError' is TRUE and 'nErrorId' is 1861 (hexadecimal 0x745). Is reset to FALSE by the execution of a command at the inputs.
nErrorId	UDINT	Contains the ADS error code or the command-specific error code of the last executed command. Is reset to 0 by the execution of a command at the inputs.

Further information

The function block FB_VN_ReadCalibrationResult loads the calibration results from a file asynchronously into the PLC.

	Loading of changed calibration results. When loading the calibration results, the vision service caches the data internally. Loading modified results is therefore not possible in the standard system. To do this, adjust the cache settings or see the sample Serial loading of images to the PLC for an alternative.

Parameter

Some parameters are described centrally in the section File Access Parameters.

Calibration results

The loaded calibration results can be accessed via the following variables after a successful read operation:

// Calibration results
aCameraMatrix            : TcVnMatrix3x3_LREAL;
aDistortionCoefficients  : TcVnArray8_LREAL;
aRotationMatrix          : TcVnMatrix3x3_LREAL;
aTranslationVector       : TcVnVector3_LREAL;

Application

Loading the calibration results from the path C:\TcVision\ CalibrationResult.json looks like this, for example:

fbReadCalibrationResult(
        sFilePath                := 'C:\TcVision\ CalibrationResult.json', 
        aCameraMatrix            := aCameraMatrix,
        aDistortionCoefficients  := aDistortionCoefficients,
        aRotationMatrix          := aRotationMatrix,
        aTranslationVector       := aTranslationVector,
        bRead                    := TRUE,
        nTimeout                 := T#500MS);

IF NOT fbReadCalibrationResult.bBusy AND NOT fbReadCalibrationResult.bError THEN
    // calibration results are accessible
END_IF

Related function block: FB_VN_WriteCalibrationResult.

Required License

TC3 Vision Base

System Requirements

Development environment	Target platform	PLC libraries to include
TwinCAT V3.1.4024.54 or later	PC or CX (x64) with PL50, e.g. Intel 4-core Atom CPU	Tc3_Vision