June 20, 2010
June 20, 2010
June 23, 2010
Electrical and Computer
15.113.1 - 15.113.9
A Web Service and Interface for Electronic Device Characterization
User access to lab instruments is often accomplished with heavyweight program extensions such as LabView applets and plug-ins, which do not provide quick and simple remote instrument con- trol. Instead, growing support for Web Services (WS) has recently enabled lightweight XML messaging for instrument control and measurement readings. Here we report the development of a WS and website interface designed for remote measurements of electronic devices, with class- room and Internet-wide applications. Using standard browsers (e.g. Firefox, Safari even on an iPhone) without additional plug-ins, remote users control a Keithley 2612 source-measurement unit and monitor results in real time from any computer connected to the network. This interface presently allows users to perform a variety of typical transistor measurements, but can be ex- panded to future applications in micromechanical or bio/nano device testing.
Instruments for electrical testing may be connected and controlled by a computer for data capture via the IEEE-488 general purpose interface bus (GPIB) or through Ethernet ports utilizing the VXI-11 protocol.1 This has ushered in an era of remote instrument control for virtual laboratories as the World-Wide-Web (WWW) and WWW-capable instruments have become ubiquitous. While web-based remote instrumentation control has been investigated for over a decade, these environments have generally centered on Java server software, PHP Hypertext Processor (PHP) server scripts, or direct control via LabView.1-4 Previous LabView implementations of remote electronic measurements require users to download either a ~100 megabyte LabView plug-in or a specific Java Runtime Engine,5 in addition to having a compliant browser.6 Other remote labo- ratories required LabView or XWindows to be downloaded.7
The advent of Web Services (WS) enables the connectivity between vastly different computing services by combining the Hypertext Transfer Protocol (HTTP) for universal communication that does not depend on opening other network ports,8 and the Extensible Markup Language (XML) for universally parsable text data transfer.9 A WS is a standardized means to expose the inputs and outputs of a process to a variety of other remote systems using standardized messaging pro- tocols. The service-oriented model presented by WS has been successfully used for remote in- strument control middleware with many possible interfaces.9-10 Representational State Transfer- based (ReSTful) WS are a class of WS in which messaging is accomplished by having the client send requests using HTTP (e.g. GET, PUT, POST, and DELETE) while receiving XML re-
Server Server Nanotube, Electrical Nanotube, GPIB Keithley 2602 2612 graphene, or Connection graphene or WWW WWW Intel CMOS Intel CMOS User User
Figure 1. Schematic of user interaction with remote instrument and device via WWW interface.
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