FileOpenR

Description

This function block opens a file for reading.

Files must be closed using the FileClose function block.

• 
  
• The controller allows only 32 open files at any given time.

Figure 7-208: The FileOpenR function block

Related Functions

FileClose, FileEOF, FileOpenA, FileOpenW, FileReadLine, FileReadBinData, FileSeek, FileWriteBinData, FileWriteLine

Arguments

Input

Execute	Description	On the rising edge A rising edge is the transition of a digital signal from low to high. It is also called positive edge request to open a file
	Data Type	BOOL
	Range	0, 1
	Unit	n/a
	Default	—
Path	Description	The path of the file to open or create.
	Data Type	STRING
	Range	n/a
	Unit	n/a
	Default	—

Output

Done	Description	If TRUE, then the command completed successfully
	Data Type	BOOL
Error	Description	If TRUE, an error has occurred
	Data Type	BOOL
ErrorID	Description	Indicates the error if Error output is set to TRUE. See the table in Search IndexFile and TCP/IP Function Block ErrorID Output
	Data Type	DINT
ID	Description	ID of the open file.
	Data Type	UDINT

Example

Structured Text

(* FileOpenW example *)
(* Replace FileOpenW with FileOpenA or FileOpenR as needed*)
CASE StepCounter OF
0:
   Inst_FileOpenW(TRUE, 'Results.txt');
   StepCounter := StepCounter + 1;
1:
   Inst_FileOpenW(TRUE, 'Results.txt');
   IF Inst_FileOpenW.Done THEN
      ResultsFileID := Inst_FileOpenW.ID;
      Inst_FileOpenW(FALSE, '');
      StepCounter := StepCounter + 1;
   END_IF;
END_CASE;