Optimize Your Automation with Distributed Intelligence

With powerful control and analysis algorithms deployable on any target, National Instruments LabVIEW has emerged as the development environment of choice when it comes to programming intelligent nodes to optimize automation. Intelligent nodes can be PCs; programmable automation controllers (PACs); and programmable logic such as FPGAs, DSPs, or microprocessors deployed as part of your automation system to help achieve faster changeover times, better quality, reduced waste, and increased throughput. NI LabVIEW 8 builds on the open architecture and I/O support of the LabVIEW graphical development platform and adds distributed intelligence technology to streamline building and managing large automation systems. With LabVIEW 8, you not only can add more intelligent nodes to your automation system with accurate sensing, real-time analysis, automated inspection, and precision motion, but you also can easily "talk" among distributed nodes to communicate throughput and faults, generate reports for enterprise systems, and seamlessly integrate with existing programmable logic controllers (PLCs) and other devices in your automation system.

Machine-to-Machine Communication with Shared Variables
One of the primary challenges faced by automation engineers building complex automation systems is the tight integration of multiple intelligent subsystems for motion control, logic, process control, vision, monitoring, enterprise connectivity, and machine-to-machine communication. Consider an example where your automated packaging application includes distributed intelligent subsystems for monitoring and control. You may have a PXI-based PAC for vibration monitoring on the bearings in your system. A PAC such as the National Instruments Compact Vision System inspects labels as your finished products roll out on the production line. PACs such as National Instruments Compact FieldPoint optimize process control with multiple PID loops for reliable temperature control. FPGA-based PACs like National Instruments CompactRIO manage high-performance motion control operations and fault handling. PLCs help sequence these multiple operations. In the past, machines were less complex and engineers implemented the aforementioned operations using gears and cams connected to a single motor via a line shaft. With today's servo-driven machinery, you need multiple intelligent subsystems to communicate with each other to accomplish a common task. While Ethernet has emerged as a common thread to tie all these distributed pieces together, programming communication interfaces with TCP/IP functions is not trivial and may result in added system complexity or suboptimal performance.

Just as local and global variables have facilitated communication within and across LabVIEW VIs on the same machine, new shared variables in LabVIEW 8 can help you read and write live data among multiple machines across the network. A shared variable is similar to a PLC tag that you can bind to an I/O channel or data value and is accessible from any intelligent node on the network. You now can configure shared variables in LabVIEW 8 to establish machine-to-machine communication among these intelligent subsystems. The FPGA-powered PAC immediately can shut down the system if the vibration monitoring system reports a negative status or can activate a solenoid to remove a defective piece from the conveyor line based on data from the PAC for inspection.

Figure 1. With the new shared variable in LabVIEW 8, you achieve easy machine-to-machine and machine-to-enterprise communication.

You can configure and implement shared variables with little or no block diagram programming. You can configure shared variables to have data sources such as data acquisition channels from the NI-DAQmx I/O server for connectivity to all NI data acquisition devices; the FieldPoint I/O server for connectivity to all NI FieldPoint devices including the new networked cFP-1808 Ethernet backplane; the Modbus TCP I/O server for connectivity to third-party gateways for PROFIBUS, DeviceNet, or wireless protocols; and any user-defined I/O server through the LabVIEW Datalogging and Supervisory Control (DSC) Module. You can access data from a shared variable using front-panel binding, the shared variable node in the block diagram, DataSocket functions, or the VI Server interface. Shared variables greatly simplify machine-to-machine communication.

Machine-to-Enterprise Communication with LabVIEW 8
To reduce inventory and streamline the supply chain, manufacturers are implementing lean manufacturing techniques like "just in time" (JIT) and "pull to order." Companies such as Dell and Toyota ensure that parts and materials arrive at the production line only when needed. To implement such technology, you need tight integration between the systems that manage inventory and the machines that manufacture the final product on the production floor. Being able to communicate with databases like Oracle via structured query language (SQL) is an important requirement for machines. Modern systems use eXtensible Markup Language (XML) for machine-to-enterprise communication. Machines also need to be able to react quickly to any deviation from normal operation -- whether this means sending e-mail or SMS messages to key personnel when faults are detected or being remotely controlled via a Web browser or a PDA in case corrective action is needed.

LabVIEW includes a variety of features to help you implement effective machine-to-enterprise communication. LabVIEW 8 includes a new Class Browser feature that you can use to select available object libraries, such as ActiveX and .NET, and to view classes, properties, and methods within the selected object library. LabVIEW toolkits for statistical process control (SPC), database connectivity, and Internet connectivity help you connect to popular databases such as Oracle, Microsoft Access, Microsoft SQL Server, dBASE, and more. LabVIEW also supports OLE for Process Control (OPC) for information exchange among disparate automation devices. LabVIEW 8 includes compatibility with OPC Data Access 3.0 -- a recent addition to the OPC specification that increases performance and reliability for accessing real-time data from process control hardware and software.

LabVIEW 8 also adds alarming, scaling, and logging capabilities to the LabVIEW shared variable feature with the LabVIEW 8 DSC Module. All it takes is a right-click on the shared variable to enable alarms if the temperature goes too high, to log data or events that caused the fault condition, and to scale values to real-world units for effective reporting. With the new LabVIEW 8 PDA Module, you now can programmatically dial phone numbers or send SMS messages directly from your PDA if a fault condition is detected. LabVIEW 8 introduces XControls to create custom controls and indicators that have built-in intelligence. With XControls, your temperature indicator can display results in different ranges with different fault conditions depending on your task.

Building and Managing Intelligent Automation Systems with Project Explorer
Establishing machine-to-machine and machine-to-enterprise communication is an important part of building complex automation systems, however managing multiple intelligent nodes in a distributed environment can be quite a challenge. You need a single development environment that assists you in building and managing these intelligent subsystems based on PC, PAC, or embedded technologies; supports a variety of I/O disciplines; and helps you use multiple programming architectures like data flow and state diagrams.

While LabVIEW always has provided a single development environment for multiple I/O disciplines, the new LabVIEW Project feature in LabVIEW 8 helps you manage the development and deployment of distributed intelligent subsystems. You can use projects to manage different targets, group files, create build specifications, and deploy or download files to multiple targets. These include Windows, LabVIEW Real-Time, LabVIEW FPGA, and LabVIEW PDA targets. With the LabVIEW Project, you can simultaneously open and run VIs on different targets, greatly simplifying development for multiple intelligent subsystems.

Figure 2. The new LabVIEW Project feature helps you manage multiple intelligent subsystems based on PC, PAC, or embedded technologies.

Optimizing Automation with PACs Powered by LabVIEW 8
LabVIEW 8 makes it easier to optimize automation with PACs like CompactRIO, Compact FieldPoint, Compact Vision System, and PXI by establishing machine-to machine communication among PACs and with other PLCs in the system. LabVIEW 8 also makes machine-to-enterprise communication easy and helps you manage multiple intelligent nodes in your automation system with the new LabVIEW Project feature.

Rahul Kulkarni
Product Marketing Manager
Industrial Data Acquisition and Control
rahul.kulkarni@ni.com

Learn more about how LabVIEW 8 features can help you optimize your automation applications.

This article first ran in the Q4 2005 LabVIEW Special Edition issue of Instrumentation Newsletter.

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