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Summary: DDE communication between InTouch and the
WinWedge Serial Server can be set up in different ways, depending on the
requirements of the application involved. In a typical application, InTouch
is used with
WinWedge to bring data in from a serial device, display it on a window
in InTouch or send a command out to the serial device. The following is a
guide that will
help you configure WinWedge links which would be best for your application
and
how to quickly set up these links.
1. The MODE
of WinWedge must be configured as a DDE Server.
2. The COM port that will be used to communicate with the serial
device needs to be configured. WinWedge requires the normal serial connection
configuration - Baud rate, Parity, Data Bits, Stop Bits, Flow Control,
and the Buffer size. These will need to be matched to the serial device
that is being read. The COM port can be analyzed to determine the type
of signal being sent from the serial device. For DDE communication, WinWedge's
topic will be the COM port being used by the serial device.
3. The Input Record Structure needs to be defined. Since Software
Wedge has no way of knowing the type of information it will be receiving
from the COM port, it allows you to configure the Start and End of Record
Events. Please refer to the WinWedge manual for the different options.
4. The valid item addresses need to be defined using the Input Record
Definition Editor - DDE Server Mode. This dialog will come up in Software
Wedge after the Input Structure has been defined. Depending on the number
of fields per data record, the valid item addresses are Field(n) where
n is the field number defined in Software Wedge.
5. If it is necessary to send messages out the COM port, an Output
Buffer DDE Link will need to be defined. An Output Buffer DDE Link is a
one-time write which allows InTouch to act as a server for Software Wedge.
The Output Buffer DDE Link would have View as the DDE Application, Tagname
as the DDE Topic, and a user defined Tagname in WindowMaker as the DDE
Item. The user defined Tagname can either be a memory tag (if it is changed
only in InTouch) or a DDE tag (if communication to another program other
than Software Wedge is desired).
In this case, InTouch is the client (requesting
application) and WinWedge is the DDE server. All points read
from the serial device via WinWedge Serial server need to
be defined as DDE tagnames in InTouch. Valid item names are
defined in WinWedge's Input Record Definition Editor. For
example, a typical tag would be defined as follows:
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Tagname: Product1
Type: DDE Message
DDE Access name: BarCode
Application / Server name: Winwedge
DDE Topic Name: COM2
Item: Field(1)
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When WindowViewer first starts or when this tag is active,
InTouch lets the server know that the point needs to be updated.
Once initialized, the I/O server will check for the point
to change in the serial device and will advise InTouch when
its value changes. If the tag is not active in InTouch or
if its value does not change in the serial device, the server
will not advise InTouch of the point's value. This makes
communication between InTouch and the I/O server very efficient.
In this case, InTouch is the client (requesting application)
and the WinWedge is the DDE server. All points read from
the serial device via the WinWedge Serial server need to
be defined as DDE Tagnames in InTouch.
For DDE communication, the DDE application name for the WinWedge is "WINWEDGE" and
the DDE topic will be the COM port that the Wedge is set up for (i.e. COM1, COM2,
etc.)
Because the Wedge can parse incoming data records into individual data "Fields" the
valid item addresses are "Field(1)" through "Field(n)" where
n is the number of the data field as defined in WinWedge.
For example, a typical tag would be defined as follows:
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Tagname: Product 1
Type: DDE Message
DDE Access Name: AnyNameYouWant
Application/server Name: WinWedge
DDE Topic Name: COM2
Item: Field (1) |
When WindowViewer first starts
or when this tag is active*, InTouch lets the server know
that the point needs to be updated. Once initialized, the
I/O server will check for the point to change in the serial
device and will advise InTouch when its value changes. If
the tag is not active in InTouch or if the value does not
change in the serial device, the server will not advise InTouch
of the point’s value. This makes communication between
InTouch and the I/O server very efficient.
*Points are active in InTouch when they are:
- On an open window
- Historically logged
- Alarmed
- In a real-time trend
- Advised from another DDE Client
- Used in a script
Related Links
Controlling WinWedge from InTouch |
