In a computer integrated manufacturing system, shop floor control needs to access state and data information at a supervisory control level for SPC (stochastic process control) or SQC (stochastic quality control) purposes. While more and more shop floor control packages provide an open system operating environment, most supervisory control that directly relates to equipment control communicates in a proprietary (i.e., closed) environment, thus making data integration less direct and requires general customized design. We present the development of a data acquisition agent that allows users to collect state and data from multiple pieces of RS-232 accessible equipment (supervisory control level) and to forward to an SQL database server at a workstation (shop floor control level) over a TCP/IP communication network. More precisely, on a Windows-based PC, a Visual Basic application program is designed to be capable of: (i) collecting data and state information in database tables of Access format, and (ii) providing the capability of transferring database tables over TCP/IP to a database server of an SQL relational database at a remote workstation. Also shown in this tutorial is the construction of a SQL database server located remote site accessible by the PC.
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