User Program - While at the Beamline - BluIce - EPICS Interface
ATTENTION: This page describes
a previous version of GM/CA user interface software that was replaced by
JBluIce in May of 2010. This page
may be helpful for understanding the architecture of GM/CA control
system that did not change in the course of transitioning to JBluIce, but for
the look and feel of present system and the latest updates please refer
to the JBluIce page.
Our beamline control software is based on a combination of EPICS and SSRL BluIce. The software is available for downloading
here. EPICS is a
toolkit for designing distributed control systems and BluIce is a control
system for macromolecular crystallography beamlines popular due to its
convenient all-in-one interface. The way these two systems interact with each
other at GM/CA beamlines is presented on the figure below.
In the original SSRL design, BluIce is a full-scaled distributed control
system consisting of three software layers: GUI, DCSS (distributed control
system server, or "dispatcher" layer coordinating different hardware servers
and instances of the GUI), and multiple DHS (distributed hardware servers).
The bridge between BluIce and EPICS was made possible due to redesigning of
DCSS and DHS layers. DCSS was removed and its functions were delegated to
EPICS servers. The DHS were converted into a set of EPICS-DHS controllers
(Support, Motion, CCD, Scaler, Shutter, MCA, and etc.; one per device type)
and merged with the GUI into single application. As a result, BluIce became
a compact EPICS client application of the same class as MEDM, Striptool, and
etc. Since the DCSS and DHS layers were hidden from users, the redesign did
not have any impact on BluIce user interface. The structure of BluIce
integrated into EPICS is shown on the figure below.
The way BluIce and EPICS interact with each other is illustrated on the following figure.
When a motor is moved from BluIce this is visible in EPICS environment and vice versa.
As of May 2010, the following BluIce tabs are functional (see
JBluIce page for the most recent look and feel):
On the Hutch Tab users can change energy, attenuate the beam, open/close shutter,
control slits, position CCD detector and do point-and-click sample centering
with low-res and hi-res video cameras.
The Sample Tab complements the Hutch tab with a bigger view of sample video,
controls of light intensity, collimator, beamstop and fine adjustments of the
The Raster Tab Provides controls for searching tiny optically invisible
crystals and finding good spots on poorly diffracting crystals.
On Collect tab users can compose frame collection sequences and view
On Scan tab users can acquire fluorescent spectra and perform fluorescence
scans around chosen absorption edge in either automatic or advanced controls
The Screening Tab contains all the controls needed for screening crystals
and their indexing with WebIce. This Tab also provides controls for the sample
BluIce also includes automated sample centering and scripts for automated
beamline alignment after changing energy.