June 15, 1997
June 15, 1997
June 18, 1997
2.29.1 - 2.29.7
A Networked Instructional Instrumentation Facility
Stephan C. Werges, David L. Naylor Department of Electrical Engineering and Computer Science, University of Illinois at Chicago
The Networked Instructional Instrumentation Facility (NIIF) is a prototype system to allow multi- user access to a library of sophisticated test equipment for measurements on a library of devices, in real time via the World Wide Web (WWW). This prototype system is the first realization of our primary goal to make measurement equipment available in real time to a broad range of users via the WWW. Since the NIIF is available on the WWW for public use, there are many special design issues that must be considered. These issues include: 1) The efficient scheduling and queuing of measurement jobs that may take one or more instruments to perform; 2) Security precautions to prevent malicious use of the facility; 3) Making the NIIF fault tolerant and robust; and 4) Designing the client user interface to be intuitive and easy to use for a wide range of users. To meet these challenges we have developed an object oriented client/server architecture and a Measurement Applications Programming Interface (MeAPI) for the NIIF.
The basic architecture for the NIIF server consists of four integral parts: instrument objects; the control objects; measurement objects; and job objects. The instrument object is the lowest level object in the server, and allows the server to communicate with the instruments that are physically or logically attached to the server. These instrument objects conform to the MeAPI, which allows them to plug in to the control object. The control object is responsible for the validation, queuing and scheduling of measurement jobs, control of the matrix switch that connects test equipment to test devices, communication with the client, and control of the instruments. The control object uses a measurement object to define what instruments and parameters are needed for a given measurement. Lastly, the job object contains the client information that the control object needs to perform a measurement and returns the data to the client.
The NIIF's client architecture consists of two parts: the send object, and the receive object. The send object allows the user to choose a type of measurement, a set of specific measurement parameters, and a device to test. This object collects the measurement parameters, and sends the data to the server. The receive object listens for incoming data from the server and allows the data from the server to be displayed in a variety of different ways. This paper will describe how the object oriented client/server architecture described above and MeAPI is implemented to meet the special design requirements of the NIIF.
The explosion of the Internet and especially the World Wide Web (WWW) has revolutionized how the public obtains and deals with information. The WWW has given the public a simple way to access vast repositories of on-line information, but the paradigm for this access has been predominantly a static client/server model. Over the past two years, this static client/server
Werges, S. C., & Naylor, D. L. (1997, June), A Networked Instructional Instrumentation Facility Paper presented at 1997 Annual Conference, Milwaukee, Wisconsin. https://peer.asee.org/6705
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