Software Components for Data Acquisition

G.M. Cooper, R. Aguilar, T. Kluegel, R. Nelson, J. Ross, J. Sandoval, J. Seal, P. Trujillo, and B. Williams
Los Alamos National Laboratory

In support of new neutron scattering instruments in design at the Los Alamos Neutron Science Center, we have initiated the development of a new data acquisition system. This paper will identify and demonstrate work in progress with a focus on the software components.

To control development costs, enhance flexibility, and facilitate rapid development, we have integrated key third-party software packages: EPICS (the Experimental Physics and Industrial Control System), VxWorks from Wind River, Visual Cafˇ from Symantec, IDL from Research Systems, and Internet Information Server from Microsoft.

Our fundamental software strategy is to extend EPICS from a world of slow controls into an environment that includes "simple" high-speed data acquisition. In this context simple data acquisition means each event is characterized by a few parameters (<10) that can be processed in real time and the results recorded in a histogram in memory. For EPICS this histogram becomes a new type of record to manage in IOCs - real time Input/Output Computers that run VxWorks - and associated databases and applications.

We use SymantecÕs Visual Cafˇ to visually build graphical user interfaces (GUIs). Both indicators and controls for EPICS I/O channels are available as Java "beans" that may be dropped into place on panels that comprise the GUI. Other components provide access to data acquisition run controls, database contents, and visualization controls. Visual Cafˇ generates Java code that allows the GUI to be run as an applet by users of the World Wide Web. Thus data acquisition is no longer limited to on-site users.

Our Web-based image generation is accomplished through ION, "IDL On the Network" from Research Systems. This variant of the familiar IDL visualization package permits a Web browser to remotely run and display IDL-based applications.

Finally, control functionality, monitor data, and results are served to the applet by way of MicrosoftÕs Internet Information Server. It runs on a host machine that controls user access and data flow to and from the experiment hardware.

(posted 18-Nov-97 jw)