User Program - While at the Beamline - BluIce - EPICS Interface

Our beamline control software is based on a combination of EPICS and SSRL Blu-Ice. The software is available for downloading here. EPICS is a toolkit for designing distributed control systems and Blu-Ice is a control system for macromolecular crystallography beamlines popular due to its convenient all-in-one interface. The way these two systems ineract with each other at GM/CA beamlines is presented on the figure below.

In the original SSRL design, Blu-Ice 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 Blu-Ice 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, Blu-Ice 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 Blu-Ice user interface. The structure of Blu-Ice integrated into EPICS is shown on the figure below.

The way Blu-Ice and EPICS interact with each other is illustrated on the following figure.

When a motor is moved from Blu-Ice this is visible in EPICS environment and vice versa.

The following Blu-Ice tabs are currently functional:

On 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.

On Collect tab users can compose frame collection sequences and view acquired images.

On Scan tab users can acquire fluorescent spectra and perform MAD scans around chosen absorption edge. images. Next plans for Blu-Ice include implementation of automated sample centering, controls for sample mounter, controller for bimorph focusing mirrors and scripts for automated beamline alignment after changing energy.