FB_VN_WriteContainer
This FB writes a container as an xml file to the hard drive.
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 |
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_XMLTCVN_CEF_XML_SERIALIZEDTCVN_CEF_CSVTCVN_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. 4024.44 or later | PC or CX (x64) with PL50, e.g. Intel 4-core Atom CPU | Tc3_Vision |