Recommended Procedure for System Specification and Design: Automation of a Gas Chromatograph — Mass Spectrometer System

Too often the development of laboratory automation systems has proceeded without adequate specifications or design. It is not unusual to find systems which are orders of magnitude too powerful—or, conversely, grossly inadequate—for the automation tasks required. A typical pitfall involves the specification of computer hardware independent of any detailed consideration of the real requirements of the laboratory instrumentation. Presented here will be an outline of a recommended approach to laboratory automation design. This approach recognizes three steps in the development of an automation system: user-level specifications of objectives and constraints; preparation of a hardware-independent functional design; and implementation of the design with specific hardware/software components. Thus, the selection of system components is not made until after the functional characteristics of the system are defined. At this point, hardware/software tradeoffs can take place to achieve an optimum configuration. A specific example will be discussed here to illustrate this approach. The example involves the development of a computer-automated gas chromatograph-mass spectrometer laboratory instrument for nonroutine analytical investigations.