FileExists
Description
This function block tests if a file exists.
Figure 7-205: The FileExists Function Block
Related Functions
FileCopy, FileDelete, FileRename, FileSize
See also: File Management
Arguments
Input
Execute | Description | On the rising edgeA rising edge is the transition of a digital signal from low to high. It is also called positive edge test to see if a file exists |
Data Type | BOOL | |
Range | 0, 1 | |
Unit | N/A | |
Default | — | |
Path | Description | The path to the file |
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 | |
Exists | Description |
The existence of the file. True: this value indicates the file exists False: this value indicates the file does not exist. |
Data Type | BOOL |
Example
Structured Text
(* FileExists example *)
CASE StepCounter OF
0:
Inst_FileExists(TRUE, 'Test.txt');
StepCounter := StepCounter + 1;
1:
Inst_FileExists(TRUE, 'Test.txt');
IF Inst_FileExists.Done THEN
TestFileExists := Inst_FileExists.Exists;
Inst_FileExists(FALSE, '');
StepCounter := StepCounter + 1;
END_IF;
END_CASE;