When Accelemetrics, a supplier of gas measurement software solutions, was looking to provide an OPC interface in its CommFidence software application, it had no desire to become an OPC expert and be in the software driver business. Accelemetrics President Danny Lee visited Software Toolbox in the OPC Foundation booth at the 2004 ISA Expo, and chose its tools to provide OPC client connectivity. Software Toolbox, based in Matthews, N.C., provides a wide variety of OPC solutions and is a charter member of the OPC Foundation. Lee states, “The Software Toolbox OPC Data.NET component has allowed Accelemetrics to focus on strategic .NET development activities, instead of delving into the details of OPC. This was particularly important to us, as we had a lot to do to implement our domain specific expertise in this application.”
Accelemetrics’ CommFidence is a hybrid application with powerful features found in large-scale supervisory control and data acquisition (SCADA) and human-machine interface (HMI) systems. Many energy companies have simple “data collection” systems that do not have any SCADA or HMI capabilities. CommFidence falls into the middle range between these two categories of software.
CommFidence provides a straightforward alarming system suited for hundreds to thousands of similar devices, with a limited number of data points. It is not intended to replace a general purpose HMI system, but instead takes a more vertical approach to provide specialized data alarming and system monitoring solutions, primarily in the oil and gas industry. CommFidence works with any OPC Data Access Server, including the Software Toolbox TOP Server and servers with a particular focus on energy data collection systems, such as AutoSol.
Frozen values
A particularly important problem that CommFidence solves for its users is a type of specialized alarm detection known as “frozen values.” For example, a pressure transmitter might fail with the pressure frozen at a certain value. Gas flow computers frequently communicate with other intelligent devices, such as gas chromatographs. If the flow computer should fail to communicate, or if the gas chromatograph should fail to analyze the gas, the value returned from the flow computer via OPC will be frozen. The mole component analysis from the chromatograph is used directly in the calculations to generate gas volume and heat content, so this type of failure can have a significant financial impact, especially if a pipe is moving millions of cubic feet of gas per day. CommFidence can find this type of problem in minutes, instead of waiting for the problem to show up in an hourly data report. This type of “frozen value” alarming is not typical in other HMI or SCADA systems.
CommFidence provides a multi-window Viewer application to display alarms and device communication statistics in scrollable grid windows. Alarms are tracked as they go “into” alarm states and “return to normal,” with an option for users to acknowledge the alarms. Communication statistics, such as last poll time, number of successful polls, number of failed polls and the like, are tracked for each OPC device.
CommFidence has a convenient dual grid for viewing and editing device and item configurations. A macro ability to configure a single device and copy to multiple identical devices is a tremendous time saver. Security is provided to allow read-only access, operator access (adds the ability to acknowledge alarms) and administrative access to all rights, including configuration.
All CommFidence data is written to a Microsoft SQL Server database (optionally Microsoft SQL Server Desktop Engine, or MSDE). The primary CommFidence monitoring application executes as an operating system “service” for robust operation. All code is written with .NET programming tools, including the Software Toolbox OPC Data.NET library, a tool that has saved Accelemetrics a tremendous amount of development time. Lee adds, “The Software Toolbox team is extremely knowledgeable, enthusiastic and willing to help us however we need it. Software Toolbox has built a reputation for having the best support in the industry, which is why it is our first choice for this type of product.”
For more information on OPC solutions from Software Toolbox, visit www.softwaretoolbox.com/opc.
