FB_FileSeek

The function block FB_FileSeek sets the file pointer of an open file to a definable position.

	This function block is only suitable for logging in real-time to a limited extent. For good performance, we recommend using the TF3500 TwinCAT Analytics Logger product, which is subject to a charge.

Inputs

VAR_INPUT
    sNetId    : T_AmsNetId;
    hFile     : UINT;
    nSeekPos  : DINT;(* new seek pointer position *)
    eOrigin   : E_SeekOrigin:= SEEK_SET;
    bExecute  : BOOL;
    tTimeout  : TIME := DEFAULT_ADS_TIMEOUT;
END_VAR

Name	Type	Description
sNetId	T_AmsNetId	String containing the AMS network ID of the target device to which the ADS command is addressed (type: T_AmsNetId).
hFile	UINT	File handle, which was generated when the function block FB_FileOpen was created.
nSeekPos	DINT	New position of the file pointer
eOrigin	E_SeekOrigin	Relative position, to which the file pointer is to be moved (type: E_SeekOrigin).
bExecute	BOOL	The function block is activated by a rising edge at this input.
tTimeout	TIME	States the length of the timeout that may not be exceeded by execution of the ADS command.

Outputs

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

Name	Type	Description
bBusy	BOOL	When the function block is activated, this output is set to TRUE and remains set until feedback is received. As long as bBusy is TRUE, no new command can be executed.
bError	BOOL	If an error occurs during command execution, this output is set, once the bBusy output has been reset.
nErrId	UDINT	Returns the ADS error code or the command-specific error code when the bError output is set.

Command-specific error code	Possible cause
0x703	Invalid or unknown file handle.
0x70E	File was opened with wrong method (e.g. with obsolete FILEOPEN function block).

Example of calling the function block in FBD:

PROGRAM Test
VAR
    fbFileSeek       : FB_FileSeek;
    hFile            : UINT;
    nSeekPos         : DINT;
    bFileSeek        : BOOL;
    bFileSeekBusy    : BOOL;
    bFileSeekError   : BOOL;
    nFileSeekErrorId : UDINT;
END_VAR

Requirements

Development environment	Target system type	PLC libraries to include (Category group)
TwinCAT v3.1.0	PC or CX (x86, x64, ARM)	Tc2_System (System)