13-08-2012, 12:13 PM
VI BASED TEMPERATURE SENSING AND CONTROLLING USING NI LABVIEW
1VI BASED TEMPERATURE.pdf (Size: 3.19 MB / Downloads: 94)
INTRODUCTION
Any industry will have various parameters that are to be continuously monitored and
controlled from a remote place. In most of the cases the use of manpower becomes almost
impossible and therefore remote monitoring and control systems are extensively developed and
used.
Consider a remote application in a process industry where the temperature of various
sources at different places, need to be monitored and controlled within an acceptable tolerance.
For such an application a low-cost user-friendly programmable temperature controller compatible
with the PC for industrial purpose which has to be monitored continuously in a remote place is
required.
All this features can be implemented easily with low cost by designing a temperature
sensing and controlling unit based on a VI (Virtual Instrument) program with minimum hardware
design to acquire, analyze the data and to initiate the control action accordingly.
Virtual Instrumentation
Virtual Instrumentation uses off-the shelf mainstream computer technologies combined
with innovative, flexible software and modular high-performance hardware technologies to
create powerful computer based instrumentation solutions. The objective in virtual
instrumentation is to use a PC to mimic real instruments with their dedicated controls and
displays with the added versatility that come with software.
Virtual Instrumentation combines hardware and software with industrial standard
computerized technologies to create user-defined instrumentation solutions. National Instruments
specializes in developing plug-in, distributed hardware and driver software for data acquisition
(DAQ), IEEE 488(GPIB), PXI, serial and industrial communications. The driver software is the
application programming interface to the hardware and is consistent across National Instruments
application software, such as LabVIEW, Lab windows and Measurement Studio. These platforms
deliver the sophisticated display and analysis capabilities that Virtual Instrumentation requires.
Virtual Instrumentation Applications
Virtual instrumentation is applicable in many different types of applications, starting from
design to prototyping and deployment. The LabVIEW platform provides specific tools and
models to solve specific applications ranging from designing signal processing algorithms to
making voltage measurements and can target any number of platforms from the desktop to
embedded devices – with an intuitive, powerful graphical paradigm.
Integrated Hardware Platform
A virtual instrument consists of an industry-standard computer or workstation equipped
with powerful application software and cost-effective hardware such as plug-in boards, and
driver software, which together perform the functions of traditional instruments. Virtual
instruments represent a fundamental shift from traditional hardware-centered instrumentation
systems to software-centered systems that exploit the computing power, productivity, display,
and connectivity capabilities of popular desktop computers and workstations.
Although the PC and integrated circuit technology have experienced significant advances
in the last two decades, software truly offers the flexibility to build on this powerful hardware
foundation to create virtual instruments, providing better ways to innovate and significantly
reduce cost. With virtual instruments, engineers and scientists build measurement and automation
systems that suit their needs exactly (user-defined) instead of being limited by traditional fixedfunction
instruments (vendor-defined).
LabVIEW - Ideal for virtual instrumentation
LabVIEW is an integral part of virtual instrumentation because it provides an easy-to-use
application development environment designed specifically for engineers and scientists.
LabVIEW offers powerful features that make is easy to connect to a wide variety of hardware
and other software. This ease of use and these features deliver the required flexibility for a virtual
instrumentation software development environment. The result is a user-defined interface and
user-defined application functionality. One of the most powerful features that LabVIEW offers is
its graphical programming paradigm. With LabVIEW, engineers and scientists can design
custom virtual instruments by creating a graphical user interface on the computer screen through
which they
Measurement and control services software
Measurement and control services software is equivalent to the I/O driver software layer.
However, it is much more than just drivers. Though often overlooked, it is one of the most
crucial elements of rapid application development. This software connects the virtual
instrumentation software and the hardware for measurement and control. It includes intuitive
application programming interfaces, instrument drivers, configuration tools, I/O assistants, and other software included with the purchase of National Instruments hardware. National
Instruments measurement and control services software offers optimized integration with both
National Instruments hardware and National Instruments application development environments.
As an example, National Instruments raised the bar for data acquisition software when it
introduced NI DAQmx for the Windows OS and increased the ease, speed, and power with
which scientists and engineers take measurements. NI DAQmx leverages several technologies
that legacy drivers do not exhibit including multithreading, simplified application programming
interface (API), interactive configuration, and intelligent multi-device synchronization.
Additionally, NI-DAQmx supports broad ranges of programming languages, devices, buses,
sensors, and even mixed signal types