FB_XmlSrvWrite

FB_XmlSrvWrite 1:

The FB_XmlSrvWrite function block can be used for writing the value of a PLC variable into 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 written is identified unambiguously by the symbol address and size.

FB_XmlSrvWrite 2: 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 which data are written into the XML file. XMLSRV_SKIPMISSING and XMLSRV_ADDMISSING modes are available for the XmlSrvWrite command. In XMLSRV_SKIPMISSING mode, only those subelements of a PLC symbol that already exist in the XML file are written to the XML file. In XMLSRV_ADDMISSING mode, missing subelements are added to the XML file. From product version 3.2.31.0 it is possible to write the comments from the declaration section into the XML file with the parameters XMLSRV_SERIALIZESYMCOMMENT and XMLSRV_SERIALIZETYPECOMMENT.

pSymAddr

DWORD

Address of the PLC variable to be written to the XML file.

cbSymSize

UDINT

Size of the PLC variable to be written to 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.

Requirements

Development environment

Target system type

PLC libraries to be linked

TwinCAT v3.1 Build 4011

PC or CX (x86, x64, Arm®)

Tc2_XmlDataSrv

FB_XmlSrvWrite 3: 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.