THE APPLICATION OF GRAPHIC DESKTOP SOFT-WARE IN
SINGLE CRYSTAL DIFFRACTOMETRY.
By Dirk Abeln* and Juergen Kopf;
Institut fuer Anorganische und Angewandte Chemie der Universitaet
Hamburg, Martin-Luther-King-Pl. 6, D-20146 Hamburg, Germany.
One of the first scientific instruments to be controlled by a
computer was the single crystal diffractometer (Busing, W. R. and
Levy, H. A., Acta Cryst., 1967, 22, 457). Early
computer-contolled diffractometers were built at Hilger &
Watts (Y290), Enraf-Nonius (CAD4), Philips (PW1000) and
Siemens (AED). The programs developed for those instruments
were written in assembler, mostly for a DEC PDP-8 computer.
The first diffractometer software, completely written in the
high-level computer-language FORTRAN IV, was the control program
for the Syntex P21.
The past ten years have seen a revolution in computing and
graphics hardware with the arrival of PCs and powerful graphic
workstations which become increasingly faster and cheaper. New
desktop systems, like GEM, WINDOWS or X/WINDOWS, allow an
unexperienced user easy interaction with the computer.
In connection with the electronic rebuilding of a 22 years old,
mechanically still reliable Hilger & Watts (Y290) we have
developed a new graphically oriented program for the diffractometer
control which uses the above mentioned advantages. A new interface
(Lange, J. and Burzlaff, H., J. Appl. Cryst., 1991, 24,
190), using a 68008-based single-board microcomputer for
serving the four stepper motors of the four circles, is connected
to an ATARI Mega ST2 via the serial interface RS232. The
diffractometer control software is completely written in FORTRAN77
and has the following features:
The power of this new program Y290 is derived from a sophisticated
menu-driven user interface which is much easier to use than the
``classical'' command-line input.
- drop-down-menus, dialog-, alert- and fileselector-boxes
- fast random peakfinding routine
- rotation- and axes-photographs
- centering routine with graphical representation of reflection profiles
- fexible indexing-, lsq- and bravais-routines
- graphical simulation of precession photographs
- Psi-scan of single reflections with transmission curve
- flexible data- and Psi-data-collection output in windows
Last changed: 16-Nov-2001. Jürgen Kopf