This article was printed in CONTROL's March 2009 edition.
Bachelor Controls is a system integrator serving clients in process and other industries. When integrating control and ERP systems, they typically employ Microsoft SQL Server as a middleware transfer point, as in this recent project.
A large pharmaceutical client contracted with Bachelor to connect plant-floor software with its SAP ERP system. “Using Microsoft SQL Server as a data transfer agent allowed us to make the connections the client wanted, avoid information exchange it did not need or want, and present the information in a format it could leverage within its existing business model and procedures,” explains Jerry Leuthold, senior software engineer at system integrator Bachelor Controls.
The SQL database resides on a separate SQL Server and is used only as an intermediate storage and transfer point, not as a historian. Bachelor’s proprietary BCI Batch Engine software stores production information from bar-code readers, lot tracking and production data results. SAP stores raw materials, inventory, labor and equipment resource information.
“SQL Server brokers data back and forth between our batch engine software and SAP using relatively simple commands and well-defined data fields,” says Leuthold.
According to Leuthold, SQL Server is a big improvement on prior non-standardized methods of data exchange. “In the past, this sort of data exchange was accomplished using flat files. This required programmers and engineers to deal with a complex set of rules that made data exchange quite problematic. The more structured SQL Server simplifies the intermediate transfer language with easier definitions, so engineers and programmers can place more focus on meeting client needs and less time on technical issues and troubleshooting,” observes Leuthold.
Not only is SQL Server easier for Bachelor to implement, it’s also better for the client. “The biggest advantage of using SQL Server as an intermediate transfer point lies in the flexibility it provides the client. Competing shrink-wrap solutions work well in some cases, but many MES applications force users to either change their business processes to meet the software setup or to modify the software programming to meet their existing business practices,” explains Leuthold.
“For this application, SQL Server allowed our client to make only the specific data transactions it wanted without doing any adjustments to an off-the-shelf package. Ultimately our client received better value for its money because it only paid for what it wanted. Using a separate intermediate transfer point also provides crucial flexibility for future system changes as no re-programming is necessary―one simply updates the SQL data fields,” concludes Leuthold.