Creating LabVIEW Applications to Communicate Between PACs and the NI TPC-2006 Industrial Touch Panel Computer

For engineers implementing distributed monitoring or control applications, the National Instruments TPC-2006 provides the ideal Human Machine Interface (HMI) for interacting with and managing remote systems. The NI TPC-2006 offers an on-board processor programmable using the LabVIEW PDA Module, a rugged LCD touch panel display and interface, and an assortment of integrated I/O ports for system integration. These features make the NI TPC-2006 the best choice for interfacing with ‘headless’ networked controllers such as Compact FieldPoint and CompactRIO systems. This document describes the important features of the TPC, discusses common applications, and outlines how to effectively develop and integrate the HMI into your distributed application.

Common Applications for Distributed Intelligence

The NI TPC-2006 is an industrial touch panel computer well suited for monitoring, controlling, or otherwise interacting with distributed systems. Industrial control systems often consist of a number of independent Programmable Automation Controllers (PACs) managing specific tasks in an industrial environment. A stand-alone PAC can be used to control a relatively basic task, but as the task grows in complexity, the control duties must be split among a number of PACs. Ideally, this results in a system of controllers communicating to each other and working together to perform a difficult job. When these PACs are networked together, they serve as nodes of an intelligent distributed system to control an industrial process.

System managers and operators need a way to monitor and control such a distributed system, and National Instruments now offers a complete solution to this problem of system integration. The NI TPC-2006 industrial touch panel computer serves as a rugged and compact HMI for operators and developers of distributed industrial systems. By networking the NI TPC-2006 with National Instruments programmable logic solutions, like Compact FieldPoint and FPGA-based CompactRIO systems, engineers can now easily incorporate an industrial quality HMI for real distributed intelligence.


The key advantage of the NI TPC-2006 lies in the ability to easily develop and deploy embedded applications using the LabVIEW PDA Module. The ability to develop programs for the HMI in the familiar LabVIEW graphical programming environment, combined with its compatibility and ease of integration with other National Instruments products, allows users to easily overcome the typical obstacles of system design.

See Also:
Optimize Your Automation with Distributed Intelligence

Summary of Important HMI Features

The NI TPC-2006 features a robust and compact design that combines a powerful and efficient portable computer with a durable touch panel display and user interface. An ARM9 fanless microprocessor running at 266 MHz provides the perfect balance of performance and minimum power consumption. The 5.7” LCD display, with a native 320x240 resolution, displays three-dimensional front panel controls and indicators in high-fidelity. A rugged resistive touch panel interface incorporated into the LCD display allows the user to easily interface with the computer in almost any environment. Storing and transferring data becomes possible with the onboard and removable CompactFlash memory. These basic features combined with the device’s variety of I/O connection options represent a dramatic improvement in the world of HMIs.

Hardware and Connectivity Features
· Rugged, industrial, and compact design
· Fanless processor for efficient operation and powerful performance
· Sharp LCD display incorporated with resistive touch screen
· Variety of I/O ports for integration into existing networks
· Onboard and removable FLASH memory
· Mounting system

The industrial computer components of the NI TPC-2006 run the Windows CE OS, which means that programs can be developed, compiled, and deployed to the device from the LabVIEW PDA Module development environment. The LabVIEW PDA Module includes many features, such as the PDA Project Wizard and templates for PDA VIs that make for easy and rapid application development. By standardizing development for multiple platforms, such as PACs and HMIs, under the same development environment, system engineers can realize the goal of rapid system development and integration.

Programming, Development, and Distribution
· Integration and compatibility with other NI products and systems
· Processor running Windows CE Operating System
· Easily programmable using the LabVIEW PDA Module
· LabVIEW 8 PDA Project Wizard for rapid application development
· Tools to compile, download, and execute LabVIEW PDA executables

See Also:
NI TPC-2006 Product Page

Rapid Application Development with the LabVIEW PDA Module

As distributed systems grow in complexity and functionality, developing and deploying applications to manage these systems becomes increasingly difficult. The LabVIEW graphical development environment has emerged as the leading tool for implementing complex data acquisition, analysis, and control applications. To meet the needs of developing a modern distributed architecture, LabVIEW 8 introduces the Project Explorer to easily and logically organize applications across multiple targets and programming environments. The ability to logically organize, access, and develop programs that span multiple targets in the Project Explorer allows system engineers to simultaneously develop distributed applications for PACs, HMIs, and other embedded targets in a single environment. The Project Explorer also overcomes the obstacles of application deployment by including the ability to save and execute Build Specifications that automatically compile and distribute applications to the appropriate target.

The LabVIEW PDA Module leverages these new features to streamline development and distribution of applications for Windows CE OS devices such as the NI TPC-2006. The new PDA Project Wizard guides users through creating the framework for developing, compiling, and distributing LabVIEW applications to a HMI target like the NI TPC-2006. The LabVIEW PDA Module comes equipped with VI templates that are scaled to 640 x 440 resolution for use with the NI TPC-2006 5.7" display. The development environment provides front panel controls and indicators for designing user interfaces for the compact screen of the NI TPC-2006. Specialized block diagram functions exist for developing applications specific to the Windows CE environment, including custom memory management, application control, and error checking VIs. To aid in application development and debugging, the PDA Emulator can be used to view the performance and execution of your program without having to physically deploy it. When it does come time to distribute the application, the Build Specifications Tool allows you to configure and save how the program should be compiled and deployed. These tools of the LabVIEW PDA Module allow users to successfully create and distribute programs for the NI TPC-2006.

See Also:
What is the LabVIEW PDA Module?

Client/Server Communication Architecture

The backbone of any network of distributed controllers is the communication between the nodes of that network. Because of the availability and reliability of existing Ethernet infrastructure in many industrial environments, a networking protocol such as TCP/IP is often used to perform this communication. A command-based protocol built on an architecture with multiple clients and a single server proves to be the most effective way to manage communication between embedded targets like Compact FieldPoint and CompactRIO systems, and host devices like PCs, PDAs, and HMIs. The basis for this architecture is outlined in a series of documents and example VIs, each building on the previous to provide a complete solution to creating distributed systems with HMI targets. communication.

Note: Source code is available and linked below for download, with libraries of functions that can be used to programmatically implement the communication procedure outlined in these Application Notes. You can place these utilities in the functions palette in LabVIEW by placing them in the User Library directory, located at C:\Program Files\National Instruments\LabVIEW x.x\user.lib.

1. Simple TCP/IP Messaging Protocol
A viable Client/Server Communication Architecture relies on an effective and efficient protocol for sending and receiving commands over a network. The network nodes need to be able to package and send various data types, receive and decode that data, and manipulate that information as a series of commands or raw data. The main requirement is that this protocol must be flexible and easily scalable for use in developing and maintaining communication applications. The following document explains how basic TCP/IP functions are used to create such a protocol. The source code available in the 'Related Links' section contains a library of PDA TCP/IP VIs that can be added to the function palette for use in application development.

Simple TCP/IP Messaging Protocol Application Note

2. Command-Based Architecture
Expanding on the Simple TCP/IP Communication Protocol, this next document outlines the concepts behind the Client/Server Architecture. This document discusses the necessary considerations and solutions for communicating between an embedded target and a networked host such as the NI TPC-2006, with special attention to LabVIEW Real-Time tools used to program Compact Fieldpoint and CompactRIO systems.

Command-based Architecture for LabVIEW Real-Time

3. Managing Connections Between Clients and Servers
This final Application Note describes how to implement the tools and concepts discussed in the previous documents to implement a connection manager for a distributed system. The source code available in the 'Related Links' section contains a library of Connection Manager VIs that can be added to the function palette for use in application development.

Building a Multi-Client Single Server Distributed Architecture Application Note

The Client/Server Communication Architecture for distributed systems requires an understanding of how the basic messaging protocol sends and receives data, how communication functions should be implemented in clients and servers, and how connections between targets should be managed and optimized.

See Also:
TCP/IP Connection Manager Example Code
Simple TCP/IP Messaging Protocol for HMIs Example Code

Conclusion

The NI TPC-2006 is the ideal solution for adding an industrial HMI to a distributed PAC system. System engineers can rapidly integrate the NI TPC-2006 into their networks by programming and deploying applications to the HMI using the LabVIEW PDA Module. The Client/Server Command Based Communication Architecture ensures efficient, effective, flexible, and scalable communication for distributed systems, resulting in a top-down National Instrument solution for the future of distributed intelligence.
Related Links:
HMI and Industrial Touch Panels

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