FB_XmlSrvRead

The function block FB_XmlSrvRead can be used to initialise a PLC variable with data from an XML file. The input variable sXPath has to point to a valid node in the XML file specified via sFilePath. The symbol to be initialised is identified unambiguously by the symbol address and size.

Inputs

VAR_INPUT
    sNetId      : T_AmsNetId; 
    ePath       : E_OpenPath := PATH_GENERIC; 
    nMode       : WORD := XMLSRV_SKIPMISSING;
    pSymAddr    : DWORD;
    cbSymSize   : UDINT;
    sFilePath   : T_MaxString;
    sXPath      : T_MaxString;
    bExecute    : BOOL; 
    tTimeout    : TIME := T#60s; 
END_VAR

Name	Type	Description
sNetId	T_AmsNetId	String containing the network address of the TwinCAT 3 XML Server. For the local computer (default) an empty string may be specified.
ePath	E_OpenPath	This input can be used to select a TwinCAT system path on the target device for opening the file.
nMode	WORD	This input can be used to control how the XML file is evaluated. Only the XMLSRV_SKIPMISSING mode is initially supported for the command XmlSrvRead.
pSymAddr	DWORD	Address of the PLC variable to be written with the data from the XML file.
cbSymSize	UDINT	Size of the PLC variable to be written with the data from the XML file.
sFilePath	T_MaxString	Contains the path and file name for the file to be opened. The path can only point to the local file system of the computer. This means that network paths cannot be used here.
sXPath	T_MaxString	Contains the address of the tag in the XML document from which the data are to be written. The address must be a valid XPath instruction. The name of the tag must be different from the name of the symbol.
bExecute	BOOL	The function block is activated by a positive edge at this input.
tTimeout	TIME	Maximum time allowed for the execution of the function block.

Outputs

VAR_OUTPUT
    bBusy   : BOOL;
    bError  : BOOL;
    nErrId  : UDINT;
END_VAR

Name	Type	Description
bBusy	BOOL	This output is set when the function block is activated and remains set until feedback is received.
bError	BOOL	This output is set up after the bBusy output has been reset if there has been an error in transmission of the command.
nErrId	UDINT	If the bError output is set, this parameter returns the TwinCAT 3 XML Server error number.

Requirements

Development environment	Target system type	PLC libraries to be linked
TwinCAT v3.1 Build 4011	PC or CX (x86, x64, Arm®)	Tc2_XmlDataSrv