Malvern Instruments Zetasizer 1000, Basic Reference Manual

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5.1 Exchange of Data with other programs
Two basic methods are available to the user. DDE (dynamic data exchange) is a message
passing system which can be used to set up a link to other applications This is essentially a
Macro program in the PCS program which is run to transmit the necessary data. This is either
done explicitly by running a program containing DDE POKE’S addressed to the partner
application (in this mode the PCS program is referred to as the ‘client’, the partner as the ‘server’).
Alternatively the client-server relationship can be reversed by ‘posting’ data as being available
from the PCS program. This is done by selecting COPY LINK from the EDIT menu.
The ‘client’ application that wants to receive the data must then provide a PASTE LINK function
which will receive the information. The actual format of the content of the data is governed by
the macro program DDELINK. This program is run, after COPY LINK is pressed, whenever the
LIVE BUFFER is updated by an analysis or file transfer operation.
Also under EDIT are COPY GRAPH and COPY TABLE which are used to place ‘pictorial’ data
on the clipboard allowing data to be ‘pasted’ into the target application. This method is referred
to as a ‘cold link’
The other method, possibly simpler in conception, is to write a variant of a page description or
other Macro program containing statements that write data to a file in an essentially text format.
Each of these methods are explored further below. The DDE and file methods are obviously
useful when ‘live data’ needs to be transferred, as it is available, to a spreadsheet or process
control application, for example. The clipboard method is suitable for building up a report
incorporating output from the PCS application.
5.1.1 Transferring data by DDE with the PCS program as Client
In this method of interprocess communication a Macro program run from the PCS application is
‘in charge’ of the transfer. It can run the ‘server’ application and uses special transfer statements
to send string data to that application. Since Print ... using can be used to format even numerical
data into a string form, a very flexible type of communication is possible. It is quite possible for
the user to write their own applications to communicate by DDE with the PCS program, but the
examples we shall discuss here are restricted to the PCS program sending data to ‘standard’
applications, in particular Microsoft’s Word and Excel packages. (© Microsoft Ltd.). The example
shown below will copy a single piece of data from the PCS program to Word.
The first line of the program ‘execute normal “d:\winword\winword” will run Word for Windows.
(Details of the pathname may be different on your system). It is shown as ‘commented out’ as
Word was already running when the example was being tested. With Word running the DDE
Connect statement opened DDE channel 1 to Document1, the default Word filename. A print ...
using statement is used to assign to a$ a simple zeta potential result, which is then printed to
the special DDE ‘string buffer’ with print string. The DDE poke statement sends data on DDE
channel 1, the parameter being the ‘item’. In the case of ‘Word for Windows’ this item is a so
called ‘Bookmark’, a user inserted label delineating the destination for the transferred data. The
status of the 5 DDE links allowed can be examined under View DDE Links, shown for the present
example below.
To put in the bookmark, go to Word’s Insert Bookmark menu item, and put (for example) label1
as a bookmark. When the POKEX1 is run the string (for a particular example) Zeta Potential =
22.2 will appear in document1. Note that the topic and item can be referred to via string variables
that can be set up using a ‘print string’ construct.
Advanced Features MAN 0179
Page 5.1
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