A Higher Level Language Data Acquisition System (III) - The User Data Acquisition Program

The nuclear physics group at the University of Illinois has implemented a data acquisition system using modified versions of the Concurrent Pascal and Sequential Pascal languages. The user, a physicist, develops a data acquisition "operating system", written in these higher level languages, which is tailored to the planned experiment. The user must include only those system functions which are essential to the task, thus improving efficiency. The user program is constructed from simple modules, mainly consisting of Concurrent Pascal PROCESSes, MONITORs, and CLASSes together with appropriate data type definitions. Entire programs can be put together using "cut and paste" techniques. Planned enhancements include the automating of this process. Systems written for the Perkin-Elmer 3220 using this approach can easily exceed 2 kHz data rates for event by event handling; 20 kHz data rates have been achieved by the addition of buffers in the interrupthandling software. These rates have been achieved without the use of special-purpose hardware such as micro-programmed branch drivers. With the addition of such devices even higher data rates should be possible.