Supervisory Control and Data Acquisition (SCADA) systems aren’t new; they’ve been used to monitor and control complex systems such as water and wastewater plants for years. SCADA systems have been limited to a computer equipped with PLCs (programmable logic controllers) to communicate with a network of RTUs (remote terminal units) used as monitoring and control devices. The RTUs simply measured the sensors and sent the information back to the control computer.
Today, there is a growing awareness of the value that an independently powered, programmable device with memory, such as a datalogger, adds at the remote sites. The problem has been interfacing the datalogger with the existing SCADA software.
Enter OPC, which stands for OLE for Process Control. OLE is Microsoft’s Object Linking and Embedding protocol for communications between software applications.
In the past few years, a number of very sophisticated HMI applications—including National Instruments’ LabVIEW and Lookout, Iconics’ Graphworks, CI Technologies’ CITECT, Wonderware’s InTouch—have integrated OPC as an interface between the control computer and the RTUs.
Campbell Scientific now supports the OPC standard with a LoggerNet client product, the CSI OPC Server. The CSI OPC Server acts as a "bridge" between the LoggerNet Server and a third party client. This allows you to monitor measurements, control datalogger ports and flags, and set input locations in the datalogger. The CSI OPC Server acts as a server to the SCADA software, but runs as an add-on client to the LoggerNet Server. The SCADA software can run on a different PC than LoggerNet. However, the CSI OPC Server must be running on the same PC as the SCADA software and that PC must have a TCP/IP link to the PC running LoggerNet.
Setup of the CSI OPC Server is easy. Most SCADA applications that support OPC will let you drag and drop graphical objects onto a screen and then set the properties for those objects, including the data source. Typically, SCADA software has a button or control to let you select data from "OPC Tags." Once LoggerNet is running and the CSI OPC Server is installed and registered on the SCADA computer, the CSI OPC Server automatically displays the dataloggers, data tables and values being collected by LoggerNet.
The CSI OPC Server lets you adjust input locations, flags, ports, and variables in the dataloggers right from the SCADA application. OPC provides a complete measurement and control system using Campbell Scientific dataloggers and your third party application.
To order, specify PC-OPC for one copy, or PC-OPC/10 for 10 copies.
