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The Advanced Signal Acquisition Program Alive in the ME 385 Lab

Computer automated data acquisition, signal processing, and control has been utilized in the laboratory for ME 385 (Modeling and Instrumentation for Physical System) in the School of Mechanical Engineering since the 1986 Fall semester. The system ASAP (Advanced Signal Acquisition Program) introduces digital data acquisition and signal processing principles to juniors in the School. The system consists of a dedicated software interface between an IBM compatible personal computer and a Keithley Model 570 Data Acquisition Workstation. Design criteria included, (1) user friendliness, (2) a steep but short learning curve, and (3) system versatility. This has resulted in a system which is very easy to use and can be easily expanded.

ASAP was developed in the FORTH programming language, which produces high speed, compact programs in an interactive environment. The system allows the Keithley workstation to be configured through a series of deterministic menus. Configurations available include a range of samples from 1 to 2048, a range of sample rates from 1 to 19,700 samples per second, and up to four channels of differential input with programmable gains from 1 to 1000. Three types of triggering are available, a burst trigger, an asynchronous level trigger, and the ability to trigger at user determined, asynchronous intervals. Several real time plotting configurations are available, including signal versus time with user determined sampling rates and signal versus signal. Real time control capability is also available, including a zero order hold with user controlled delay as well as a PID controller. The gain range of the controller is two orders of magnitude and systems with frequencies up to 100 Hz can be controlled. Finally, signals measured with the ASAP system can be easily uploaded to the ECN for further analysis or waveforms generated on the ECN may be down loaded to test controllers.

Those interested in further information may contact Professor Galen King in Mechanical Engineering (login: kinggb).

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