Dynamic Data Exchange (DDE)
Dynamic Data Exchange (DDE) allows other applications to "talk" to SpectraPLUS-SC -applications can send commands to the analyzer and request data in return. This powerful feature allows you to build custom signal processing solutions using SpectraPLUS-SC.
DDE is supported by all major spreadsheet programs, databases and programming languages. We recommend using Visual Basic for Applications (VBA) which Microsoft has incorporated into the latest versions of all their major applications. This provides a very flexible yet easy to learn macro language which is consistent across their entire product line. Note - DDE has support has been removed from Visual Basic (v5.0 and up); however Excel still supports DDE through VBA (Visual Basic for Applications).
DDE support consists of two major types of operations - Commands and Data Requests.
Commands are actions messages such as "Run" and "Stop" which are sent to SpectraPLUS-SC for control purposes.
Data Requests are messages such as "THD" or "Spectrum" which cause SpectraPLUS-SC to send the corresponding data values to the requesting application.
Establishing a DDE Hot Link automatically:
It is possible to set up what is known as a "hot link" wherein SpectraPLUS-SC will send an "advise" message whenever it has computed new data values. When the application receives this advise message it should then request the corresponding data. A hot link can be quickly established using the external application's <Paste Special> or <Paste><Link> menu command. For example, to establish a hot link with Excel, perform the following steps:
Highlight the Spectrum View in SpectraPLUS-SC.
Click on the <Edit><Copy> menu command in SpectraPLUS-SC
Go to Excel, highlight a destination cell and click on the <Edit><Paste Special> menu command.
Click "Paste Link" as the source type and press Ok.
At this point a "DDE hot link" will be established. Whenever the spectral data changes, the spreadsheet contents will update immediately. Any cells computed from these spectral values will be recomputed.
Estabishing a DDE link manually:
Before an application can "talk" to SpectraPLUS-SC it must first initiate what is known as a "DDE conversation". When initiating a conversation, the program must know the name of the DDE server and the topic. When requesting data, the name of the item must be known. All available Item names for SpectraPLUS-SC are documented as follows:
DDE Server name:
Topic names Supported:
DDE Data Request Items