Difference between revisions of "Library Functionality"

Revision as of 11:33, 24 October 2011

Systems Integrators and other power users sometimes need to implement communication between the Techno CNC Controller and other custom software. This is sometimes done via a DLL (Dynamic Link Library).

Given the rare and complex nature of these tasks, Techno has decided to implement a different methodology to enable this behavior.

Instead of writing code around the Techno DLL which can be difficult and time consuming, users are now advised to write a SAC script in the techno cnc interface with the ability to communicate with external software via two files dynamically stored on the hard disk. This allows for extreme flexibility, robustness and ease of programming.

Things to keep in mind:

1. When reading and writing files, make sure you're always reading the most recent line, or when writing, empty the file first.
2. Be sure to create a parser in both programs to handle all possible commands

'Example of executing a program...
Set WshShell = CreateObject("WScript.Shell")
WshShell.Run ("%windir%\notepad")


'EXAMPLE OF READING AND WRITING TO SEPARATE FILES FOR COMMUNICATION PURPOSES 
'file reading/writing stuff:
'http://msdn.microsoft.com/en-us/library/czxefwt8%28v=vs.85%29.aspx

DIM SERIAL_NUMBER
DIM TEXT_FROM_FILE
SERIAL_NUMBER=1

SENDTEXT ("COMMUNICATION")
READTEXT ()
MSGBOX("File contents = "& TEXT_FROM_FILE )

MSGBOX("Operations Complete!")


PUBLIC FUNCTION SENDTEXT (TEXT_TO_SEND)
DIM FSO, FILEOBJECT
   Set FSO = CreateObject("Scripting.FileSystemObject")
   If FSO.FileExists("C:\SAC_TO_INTERFACE.TXT") Then 
      'SOMETHING HERE IF YOU DIDN'T KNOW THE FILE EXISTED
   Else
      'SOMETHING HERE IF YOU EXPECTED IT TO EXIST AND IT DOESN'T
   End If
   'CREATE OR REPLACE THE EXISTING FILE
   Set FileObject = FSO.CreateTextFile ("C:\SAC_TO_INTERFACE.TXT")
   FileObject.WriteLine TEXT_TO_SEND & "|| " & SERIAL_NUMBER & " ||" & Now()
   SERIAL_NUMBER = SERIAL_NUMBER +1
   FileObject.Close()
END FUNCTION


PUBLIC FUNCTION READTEXT ()
DIM FSO, FILEOBJECT

   Set FSO = CreateObject("Scripting.FileSystemObject")
   If FSO.FileExists("C:\INTERFACE_TO_SAC.TXT") Then 
      'GOOD, IT SHOULD. 
   Else
      MSGBOX("FILE IS NOT PRESENT! IF YOU ARE TESTING, MAKE A FILE WITH SOME STUFF IN IT.")
      'ERROR HANDLING
      EXIT FUNCTION
   End If
   
   'OPEN THE EXISTING FILE
   Set FILEOBJECT = FSO.OpenTextFile("C:\INTERFACE_TO_SAC.TXT", 1)
   TEXT_FROM_FILE = FILEOBJECT.ReadLine
   FILEOBJECT.Close
   'Delete the line from the other software after you're sure it has been read here
   'Otherwise, be sure to read the last line of the file when you read.
   'Send TEXT_FROM_FILE to your parser
END FUNCTION