FB_VN_WriteContainer

Syntax

Definition:

FUNCTION_BLOCK FB_VN_WriteContainer
VAR_INPUT
    ipContainer   : Reference To  ITcVnContainer;
    sFilePath     : STRING;
    eExportFormat : ETcVnContainerExportFormat;
    bWrite        : BOOL;
    nTimeout      : TIME;
END_VAR
VAR_OUTPUT
    bBusy         : BOOL;
    bError        : BOOL;
    nErrorId      : UDINT;
END_VAR

Inputs

Name	Type	Default	Description
ipContainer	Reference To ITcVnContainer		The container to write
sFilePath	STRING		Full path of the file or relative path to the default directory on the target pc (e.g. only a file name). If the string is empty, a file name will be generated (containing the current time).
eExportFormat	ETcVnContainerExportFormat	TCVN_CEF_XML	Container export format (default is human readable xml)
bWrite	BOOL		Writing the container 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_WriteContainer saves a container from a file asynchronously into the PLC.

Parameter

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

Container

The container ipContainer is saved as an XML file with the specified file path.

Export format

The export format eExportFormat specifies via the enum EtcVnContainerExportFormat whether the container is to be saved in a human-readable form or serialized:

TCVN_CEF_XML
TCVN_CEF_XML_SERIALIZED
TCVN_CEF_CSV
TCVN_CEF_BINARY

The human-readable form (XML, CSV) has the advantage that entries in the container can be simply checked and edited manually. However, this can lead to rounding inaccuracies. The serialized format has the advantage that no rounding inaccuracies occur. However, the format is not easy to read or edit. The CSV format has the advantage that the data can be easily processed externally in other programs. The binary format is recommended for large amounts of data.

Application

The saving of a container in the serialized XML format in the file C:\TcVision\Container.xml looks like this, for example:

fbWriteContainer(
    ipContainer     := ipContainer,
    sFilePath       := 'C:\TcVision\Container.xml', 
    eExportFormat   := TCVN_CEF_XML_SERIALIZED,
    bWrite          := TRUE,
    nTimeout        := T#500MS);

IF NOT fbWriteContainer.bBusy AND NOT fbWriteContainer.bError THEN
    // container was written successfully to file
END_IF

Related function block: FB_VN_ReadContainer.

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