Laser-induced Fluorescence Detection Control Module

Project Overview
For this project, L’Monte designed and created a control program for an add-on device to a high-end, automated capillary electrophoresis system. The system supported a number of separation modes including capillary zone electrophoresis and isoelectric focusing. The add-on product was a laser induced fluorescence (LIF) device, which employed photomultiplier (PM) detectors. The control program for the LIF add-on was designed to allow the user to control various state variables of the PM tubes and lasers, start and stop data collection, and enable digital filtering of the data stream from the PM tubes as well as numerous other hardware functions. The program also managed data archival and allowed sophisticated, real-time graphical views of generated data.

Software Design and Methodology
The overall architecture of the add-on control program was conceived as a separate executable plus an extension DLL. This structure suggested itself because of intensive modifications, which were simultaneously being made to the main instrument control program. This structure was also appealing because it allowed a single API of new functions to be exported to the existing main instrument control program as well as that to the add-on. Because the add-on control program was designed to be spawned by the main program, the two communicated using IPC mechanisms and a proprietary communications protocol. Hardware and software development proceeded in tandem. In addition, a number of high-risk elements were identified early in the project planning stage. For these reasons, an evolutionary prototyping model was selected as the software development methodology. This model made sense because it allowed developers to first focus on high-risk elements since the outcome for these elements would determine design directions for better-understood subsystems.

Project Outcome
This project was begun in September 1996 and was finished on schedule, 10 months later. It contained 100% of its originally specified features plus a diagnostics utility, which, although not originally specified, was created to facilitate unit and acceptance testing.