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A tutorial on how to create a simple solution using common off-the-shelf software to solve a variety of manufacturing data collection needs.
Process and quality engineers, production managers, and others in the discrete and process industries are increasingly asking for snapshot and composite reports of control and production data. Their motivations for these requests are wide ranging. An engineer at one site wants machine cycle data in a spreadsheet to ponder process improvements. Another engineer wants a complex report created for each machine cycle but does not plan to look at it often; therefore, he just wants it stored in a format that any computer system can import. The list of such divergent requirements goes on and on.
Despite the diversity of their data needs, one thing they have in common is difficultly finding a simple solution. Doing an online search for data acquisition resources returns a multitude of confusing results. To address this information gap, this article clarifies some rather vague terms (see "Terminology" box), and helps readers understand why the solution to their own requirement is often different from what those terms typically refer to. To help clarify things further, a method is described that uses existing control system software to extract data in a form and location that can be opened in a spreadsheet, database or any other computer system application-including MES or ERP systems. This solution leverages Microsoft technologies commonly installed on operator interface computers.
Types of data acquisition
Because SCADA has "data acquisition" in its name, a person interested in plant data reports who searches online often gets immersed in articles about control systems. The term SCADA had a somewhat different meaning a few years ago. When mines, oil and gas fields, and other industries had scattered controllers and needed to acquire data and adjust setpoints or parameters, SCADA referred to the art of collecting this far flung data (data acquisition) and making adjustments to the controls (supervisory control) in response.
Despite the roots of the name, many current references to SCADA often refer to a PLC/HMI-based control system. This shift occurred when operator interface computers (HMIs) became a common part of just about every control system.
Another common data acquisition (DAQ) activity, which is much different from SCADA, is...