Flowdde, 2 flowdde – Bronkhorst EL-FLOW Prestige User Manual
Page 18
Bronkhorst High-Tech B.V.
EL-FLOW Prestige
9.17.084
18
3.4.2
FlowDDE
RS232 communication can be used for operating the instrument using the Bronkhorst FlowDDE server application. Dynamic Data
Exchange (DDE) provides the user a basic level of interprocess communication between Windows applications. FlowDDE is a DDE
server application. Together with a client application, either self-made or with a SCADA-program from third parties, it is possible to
create an easy way of data exchange between the flow meter/controller and a Windows application. For example, a cell in
Microsoft Excel could be linked to the measured value of the EL-FLOW Prestige and when the measured value changes, it will be
updated automatically in the Excel spreadsheet.
The FlowDDE server offers the user a different and user-friendly interface to the instrument. FlowDDE makes use of specific
parameter numbers for communicating with the instrument. A DDE-parameter number is a unique number in a special FlowDDE
instruments/parameter database and not the same as the parameter number from the process on an instrument. Node-address
and process number will be translated by FlowDDE to a channel number.
DDE-client applications communicate to the FlowDDE server by using DDE messages. Before messages can be exchanged, a DDE link
has to be made. A DDE link consists of three parts: the server, the topic and an item. For separation the characters '|' and '!' may be
used, so a DDE link in e.g. Microsoft Excel becomes: Server|Topic!Item.
For standard instrument parameters and the FlowDDE server, these are:
Server: FlowDDE or FlowDDE2
Topic: ‘C(X)’ for channel number X
Item: ‘P(Y)’ for parameter number Y
An example of a DDE link in a Microsoft Excel cell is =FlowDDE|’C(1)’!’P(8)’ to read parameter 8 of channel 1.
How to setup a DDE link with FlowDDE is described in the
help-file of the FlowDDE application and in the instruction
manual document 9.17.067. Programming examples are
available for making applications in: Visual Basic, LabVIEW
and Microsoft Excel.
When not using FlowDDE for communication with the
instrument, each parameter value is addressed by:
Node address of the instrument
Process number on the instrument
Parameter number on the instrument
Refer to section 3.9 for more information regarding
instrument parameters.
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For more information regarding FlowDDE, see document 9.17.067 'Instruction manual FlowDDE' which can be found
on: