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PDFAs companies look to optimize their existing infrastructures by adding new devices such as programmable automation controllers (PACs), it is essential that their HMI/SCADA systems are open and flexible enough to communicate to a variety of different hardware systems. The importance of an open system becomes even more critical when a company grows through acquisitions that result in different hardware platforms integrating into one system. With an open and flexible system such as National Instruments LabVIEW software and the LabVIEW Datalogging and Supervisory Control (DSC) Module, you can connect to legacy devices, programmable logic controllers (PLCs), and PACs using one software package.
Figure 1. An open, flexible HMI/SCADA system connects to both new and old hardware.
Enhanced Connectivity Options with LabVIEW DSC
OPC is a standard for communicating real-time plant data between control devices from different manufacturers. OPC was introduced in 1996 so engineers could bridge systems based on Microsoft Windows such as HMI/SCADA applications and process control hardware. For many years, engineers also have used NI LabVIEW to connect to PLCs using OPC. NI has further enhanced its OPC support with the release of new OPC servers, which include drivers for all the latest PLCs. With the new LabVIEW 8.5 DSC Module, you also can quickly debug any OPC connectivity issues using the OPC diagnostics log file.
In addition to OPC, you can connect to any Modbus device with the inclusion of 32-bit integer addressing. Modbus I/O server performance also has greatly improved with compatibility for more data types such as 64-bit signed and unsigned integers and arrays. For legacy devices that do not communicate over OPC or Modbus, you can write your own drivers using low-level protocols such as TCP/IP, UDP, and serial available in LabVIEW.
Improved HMI Infrastructure in LabVIEW 8.5 DSC
In addition to enhanced connectivity options, you can take advantage of several new features and improvements to the human machine interface (HMI) infrastructure in the LabVIEW 8.5 DSC Module to develop a high-channel-count application. With the improved Multiple Variable Editor, you can create and bind thousands of shared variables within minutes. With more spreadsheet-like features, you also can sort and search shared variables based on properties, and you can collapse and expand different columns to further reduce the time spent working with shared variable libraries.
Figure 2. An HMI application built with the LabVIEW 8.5 DSC Module shows
themultisegmented pipe.
With the new multisegment pipe control, you can draw pipes in different shapes and sizes to create an intuitive user interface. Once the HMI/SCADA system is online, you can positively affect process quality with statistical process control tools now available with the LabVIEW DSC Module. LabVIEW also can perform real-time analysis with Pareto charts so you can narrow down the primary cause for downtime.
View a webcast on connecting LabVIEW to any PLC using OPC.
This article first appeared in the Q3 2007 issue of Instrumentation Newsletter.
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