UA_Read

This function block reads values from a given node and connection handle.

Inputs

VAR_INPUT
    Execute           : BOOL;
    ConnectionHdl     : DWORD;
    NodeHdl           : DWORD;
    stNodeAddInfo     : ST_UANodeAdditionalInfo;
    pVariable         : PVOID;
    cbData            : UDINT;
    Timeout           : TIME := DEFAULT_ADS_TIMEOUT;    
END_VAR

Name	Type	Description
Execute	BOOL	The command is triggered by a rising edge at this input.
ConnectionHdl	DWORD	Connection handle previously output by the function block UA_Connect.
NodeHdl	DWORD	Node handle that was previously output by the function block UA_NodeGetHandle.
stNodeAddInfo	ST_UANodeAdditionalInfo	Defines additional information, such as which attribute is read from the UA namespace (default: 'Value' attribute) or which IndexRange is to be used. Specified by STRUCT ST_UANodeAdditionalInfo.
pVariable	PVOID	Pointer to data memory where the read data is to be stored.
cbData	UDINT	Determines the size of the data to be read.
Timeout	TIME	Time until the function is aborted. DEFAULT_ADS_TIMEOUT is a global constant, set to 5 seconds.

Outputs

VAR_OUTPUT
    Done        : BOOL;
    Busy        : BOOL;
    Error       : BOOL;
    ErrorID     : UDINT;
    cbData_R    : UDINT;
END_VAR

Name	Type	Description
Done	BOOL	Switches to TRUE if the function block was executed successfully.
Busy	BOOL	TRUE until the function block has executed a command, at the most for the duration of the "Timeout" at the input. The inputs accept no new command as long as Busy = TRUE. It is not the connection time that is monitored but the reception time.
Error	BOOL	Switches to TRUE if an error occurs while executing a command. The command-specific error code is contained in nErrID.
ErrorID	UDINT	Contains the command-specific ADS error code of the most recently executed command.
cbData_R	UDINT	Number of bytes to be read.

Requirements

Development environment	Target platform	PLC libraries to include
TwinCAT 3.1	Win32, Win64, CE-X86, CE-Arm®	Tc3_PLCopen_OpcUa