In this example, we will setup NetDDE connection in an EXCEL spreadsheet (the NetDDE Client) to read tags from a remote WebAccess SCADA node (the DDE Server) using the DDE Share configured in the previous section. This example works for Windows 2000 and Windows XP Professional.
1. Log on the Client Windows Operating System with a user name and password that is recognized by the SCADA Node Windows Security. This can be either a Domain User common to both PCs or a user account created on both PCs with the same user name and password.
2. Start EXCEL
3. Select a Cell.
4. Enter a formula with the following format:
To read data using the WebAccess example in the previous section:
If the computer name is DEMO and the tagname is SPEED
Notice that there is a single quote ( ‘ ) between the equal sign (=) and the double backslash (||). There is also a single quote after NDDE$. EXCEL is very fussy about this. The two single quotes enclose ‘\\COMPUTER\NDDE$’.
Figure 14.3 - NetDDE connection to WebAccess in Excel
5. Save the Workbook.
6. Close the Workbook.
7. Reopen the Work book.
8. EXCEL will ask if you want to update Links? Select YES.