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6.2.4.1 Procedure to find the tag number for the tag name to use in DDE applications
❖ Create DDE link from Real time viewer.
❖ Open Excel file. Three columns appear in the excel file as Name, Unit and Value as shown in the
Excel file.
➢ Name: This is tag name actually defined in the channel configuration
➢ Unit: This is unit for the tag name defined in the channel configuration
➢ Value: This is the specific cell where, process value for the tag will appear in real time.
❖ To find the DDE format for any tag in channel configuration, for a specific tag, double click at
"Value" column for the corresponding tag defined at Name. For ex: For Name= AI1 is at R2C1,
double click at cell R2C3 to see DDE format for AI1. Click on Esc button at the key board to see
process value at the cell from displaying DDE format.
❖ If any "Error" appears in any cell at excel, possible reasons is no data available at selected tag.
Check the channel configuration and make sure value is available
❖ If any "NAME" text appears in the excel file, it indicates that particular tag is not configured
properly. Tag name may not available at DAQ software.
Note:
If Excel file is not opening from the selected path, then check the following
✓ RAM size in the PC is very less. Restart the computer and then create the DDE link once
again and open the Excel file.
✓ Increase virtual memory in the PC. Please contact system administrator to check the virtual
memory settings at the PC.
My computer-properties-advanced-performance settings –advanced virtual memory.
6.2.4.2 DDE with 3
rd
Once the data is available at Excel at particular cell, then data can be exchanged with the
3
party applications like PLC, SCADA, and Visual Basic etc. If data is to be exchanged with PLC,
rd
then PLC programmer can write Visual basic macro in Excel from the following link
Excel – Tools – macro
For the source code examples, PLC programmer may check the PLC manuals for DDE
sample macros. It is also possible to exchange data from recorder to SCADA applications through
DDE.
party applications
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