EVermont is a nonprofit research and development organization that works with engineering firms, energy companies and vehicle manufacturers to spearhead design, development and evaluation of new technologies and to integrate existing technologies into alternatively fueled vehicles. Proton Energy Systems and Northern Power, both wholly owned subsidiaries of Distributed Energy Systems, were contracted by EVermont to build an advanced demonstration hydrogen fueling station in Burlington, Vt. The project was partially funded through the U.S. Department of Energy’s Hydrogen Program.
The station was designed by Proton Energy and generates hydrogen on site from electricity and water using its H-Series electrolyzer (hydrogen generator). This customized system is built to withstand Vermont’s harsh winters and uses a separate control system to start/stop the system, and to maintain appropriate temperatures within the hydrogen generator.
The station monitors hydrogen production using Northern Power’s SmartView monitoring and control software. The SmartView software contains OPC client capabilities to maximize interoperability with different control systems and typically relies on OPC servers from Kepware, based in Yarmouth, Maine, to handle the device connectivity.
For this installation, KEPServerEX was used to gather data from both an Allen-Bradley controller and from the hydrogen generator itself, which has a proprietary controller with a Modbus interface. According to Brendan Taylor, of Northern Power, “We already understood the benefits of OPC, and we have the capability of developing our own OPC servers. However, we chose KEPServerEX because it provides consistent access to a wide variety of devices and control systems, and allows us to focus resources on our core business—designing and installing integrated power systems.”
As the system neared completion, the controls engineers wanted to develop a way for the A-B controller to command the hydrogen generator to start. Dry contacts were out of the question due to input/output (I/O) constraints, and other connection methods were more complicated and expensive.
Since an OPC server was already connected to both controllers, it made sense to look for a way to link data between these items in the OPC server. Proton Energy downloaded Kepware’s LinkMaster product, and in minutes was able to implement the strategy. The LinkMaster application links an OPC item in KEPServerEX, representing an output bit from the A-B controller, to an OPC item representing the generator start bit in the Modbus-enabled controller. This method reliably solved the connection problem and saved valuable time and money on the project.
For more information about OPC solutions from Kepware Technologies, visit www.kepware.com.
