FB_FileWrite

The function block FB_FileWrite writes data into a file. For write access the file must have been opened in the corresponding mode, and it must be closed again for further processing by external programs.

	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;
    pWriteBuff : PVOID;
    cbWriteLen : UDINT;
    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.
pWriteBuff	PVOID	Address of the buffer containing the data to be written. The buffer can be a single variable, an array or a structure, whose address can be found with the ADR operator.
cbWriteLen	UDINT	Number of bytes to be written
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;
    cbWrite  : 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.
cbWrite	UDINT	Contains the number of the last successfully written data bytes. A write error indicates that the number of successfully written data bytes is less than the requested length (cbWriteLen) or zero. A write error can occur if the data carrier is full, for example. If a write error occurs, the bError and nErrID outputs are not set. Since the PLC application knows the number of data bytes to be written, it can compare the actual written length with the requested length and detect write errors. When a write error occurs, the internal file pointer has an undefined position.

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 block in ST:

File access from the PLC

Example of calling the block in FBD:

PROGRAM Test
VAR
    fbFileWrite      : FB_FileWrite;
    hFile            : UINT;
    bFileWrite       : BOOL;
    bFileWriteBusy   : BOOL;
    bFileWriteError  : BOOL;
    nFileWriteErrorId: UDINT;
    nFileWriteCount  : UDINT;
    fileData         : ARRAY[0..9] OF BYTE;
END_VAR

In the example, after a rising edge at bFileWrite, 10 bytes of the array FILEDATA are written to the file.

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)