Hello and In this tutorial I will explain how to Search files from specific keywords in a Directory. Different things but just some know-how.I will share how to do it.

Function Block

This Function Block can return all the files with specific Keywords in a directory.And it only can start a new search only if the previous search has been fully completed.

The search is completed only if bEOE is True or eCmd is eEnumCmd_Abort.

For the TwinCAT system, the search may not yet be completed if the PLC application has already found the file or directory that was sought.And If bEOE=TRUE was reached or if an error occurs, eEnumCmd_Abort is automatically executed internally.

VAR_INPUT

sNetID	T_AmsNetID	The NetworkId of the target TwinCAT system. The String can be empty for the local System.
sPathName	T_MaxString	The Directory or Directory with specific name.But Also with special wildcards(* and?)
eCmd	E_EnumCmdType := eEnumCmd_First	The Command of the FB
pFindList	DWORD	Array variable address (pointer variable) of type: ST_FindFileEntry.
cbFindList	UDINT	Array variable byte size of type: ST_FindFileEntry.
bExecute	BOOL	The command is executed with a positive edge at the input
tTimeout	TIME := DEFAULT_ADS_TIMEOUT	Maximum time allowed for the execution of the ADS command.

VAR_OUTPUT

bBusy	BOOL	True= the function block is activated
bError	BOOL	True=ADS Error
nErrId	UDINT	The Error information
bEOE	BOOL	End of enumeration was reached
nFindFiles	UDINT	Number of valid files in the buffer.

TYPE E_EnumCmdType

Enumeration command parameter used by enumeration function blocks. Not all parameters are supported by every function block!

TYPE E_EnumCmdType :
(
eEnumCmd_First := 0,
eEnumCmd_Next,
eEnumCmd_Abort
);
END_TYPE

eEnumCmd_First	Enumerate first element.
eEnumCmd_Next	Enumerate next element.
eEnumCmd_Abort	Command to abort enumeration (closes opened handles).

TYPE ST_FindFileEntry

Here is the DUT to store the result of FB_EnumFindFileList.

sFileName	T_MaxString	A null-terminated string that is the name of the file.
sAlternateFileName	STRING(13)	A null-terminated string that is an alternative name for the file.
fileAttributes	ST_FileAttributes	file attributes of the file or directory
fileSize	T_ULARGE_INTEGER	64 bit unsigned integer. The size of the file is equal to (dwHighPart * (0xFFFFFFFF+1)) + dwLowPart.
creationTime	T_FILETIME	specifies when the file or directory was created.
lastAccessTime	T_FILETIME	specifies when the file was last read from or written to.For a directory
lastWriteTime	T_FILETIME	specifies when the file was last written to

TYPE T_FILETIME

The T_FILETIME structure is a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601 (UTC).

dwLowDateTime	DWORD
dwHighDateTime	DWORD

FUNCTION FILETIME_TO_DT

This Function converts time from FILETIME format into DATE_AND_TIME format (DT),allowed minimum conforms to the value DT#1970-01-01-00:00:00 and the maximum to DT#2106-02-06-06:28:15.

VAR_INPUT

fileTime

T_FILETIME

Implementation

I will use this Function Block to implement this image browsing operation and show the properties of that image.

VAR

VAR
EnumFindFileList:FB_EnumFindFileList;
FindList:ARRAY[0..49]OF ST_FindFileEntry;
bExecute:BOOL;
commnd:E_EnumCmdType;
bBusy:BOOL;
hmiIndex:INT:=0;
bError: BOOL;
nErrID: UDINT;
bEOE: BOOL;
nFindFiles: UDINT;
hmiDisplayFileEntry:DUT_HMIFileEntry_Display;
FileTime:DT;
sBasicPath:STRING:=’file:\\\C:\FTPFiles\’;
bDisplay:BOOL;
hmiIndexDisplayBackup:INT;

END_VAR

Code

EnumFindFileList(
sNetId:=’192.168.217.146.1.1′
,sPathName:=’C:\FTPFiles\*.jpg’
,eCmd:=commnd
,pFindList:=ADR(FindList)
,cbFindList:=SIZEOF(FindList)
,bExecute:=bExecute
,bBusy=>bBusy
,bError=>bError
,nErrID=>nErrID
,bEOE=>bEOE
,nFindFiles=>nFindFiles
);

IF bExecute AND (EnumFindFileList.bEOE OR EnumFindFileList.bError)THEN
bExecute:=False;
END_IF

IF hmiIndex >=0 AND
hmiIndex <=15 THEN
hmiDisplayFileEntry.FileEntry:=FindList[hmiIndex];
END_IF
IF hmiIndex <0 THEN
hmiIndex:=15;
ELSIF hmiIndex >15 OR hmiIndex > EnumFindFileList.nFindFiles-1 THEN
hmiIndex:=0;
END_IF

IF hmiIndex <>hmiIndexDisplayBackup THEN
hmiIndexDisplayBackup:=hmiIndex;
bDisplay:=TRUE;
END_IF

hmiDisplayFileEntry.CreationTime:=
FILETIME_TO_DT(
fileTime:= hmiDisplayFileEntry.FileEntry.creationTime);

hmiDisplayFileEntry.LastAccesTime:=
FILETIME_TO_DT(
fileTime:= hmiDisplayFileEntry.FileEntry.lastAccessTime);

hmiDisplayFileEntry.LastModificationTime:=
FILETIME_TO_DT(
fileTime:= hmiDisplayFileEntry.FileEntry.lastWriteTime);

hmiDisplayFileEntry.ImagePath:=CONCAT(STR1:=sBasicPath,STR2:=hmiDisplayFileEntry.FileEntry.sFileName);

GVL.currentPath:=hmiDisplayFileEntry.FileEntry.sFileName;