Measuring strain with strain gauges tutorial developer zone national instruments figure 2. This lab explores the concept of strain measurement using a strain gage. In this project, students will use methodologies outlined in the previous labs to design and implement their own strain measurement system for a given measurement need students will determine the right sensor, signal conditioning circuit, adc sampling, software approach. Concepts covered include strain and strain gauge overview, strain gauge measurement, signal conditioning for strain gauges and ni data acquisition systems for. R3 is a dummy resistor placed perpendicular to the direction of strain, and will therefore exhibit changes in resistance only due to temperature drift. One such strain gauge is the lb11, which is a cylindrical electrical foil strain gauge suitable for use in screws to measure the axial force watch this video and learn how to integrate the cylindrical strain gauge lb11 into a measurement screw. Stress analysis strain gages gauges micromeasurements. National instruments has software options for quickly logging data to disk as well as for full programming environments for complex system architectures. A strain gauge is a sensor whose resistance varies with applied force. Labview measurements manual chalmers university of technology. This eliminates errors due to changes in excitation voltage. Measure strain using an analog bridge sensor matlab.
Then they will measure the natural frequency of the beam assembly by applying a fast fourier transform to the response of the beam due to an impulse. Itm provides software development, structural and mechanical testing services, industrial monitoring, strain gauging, and data analysis solutions to clients on six continents. A variety of instruments for use in strain related applications, from dataloggers, bridges and amplifiers to full systems. You need to consider the gage factor of the transducer gt, the gage factor of the amplifier module ga, excitation voltage requirements and gain. Nidaq is a registered trademark of national instruments corporation. Measuring strain with strain gages national instruments. How to calibrate strain gagebased transducers using di. How to calibrate strain gagebased transducers using di5b38 strain amplifiers.
Bonded metallic strain gauge it is very important that the strain gauge be properly mounted onto the test specimen so that the strain is accurately transferred from the test specimen, through the adhesive and strain gauge backing, to the foil itself. Data acquisition system instrument daq supplier hbm. Learn how to take strain gauge measurements with strain gauges using the builtin. This session introduces and explains the concepts, and techniques of measuring strain with strain gages. Compactdaq getting started tutorial national instruments. The rest of the bridge as shown in figure 2 is completed inside the prosig p8000 system. When a bridge input is selected the windmill software automatically monitors excitation voltage and performs the bridge calculation to produce a reading in microstrain. We are a group of geotechnical and electronics engineers in the uk with many years of experience throughout the world in design, manufacture and supply of intelligent sensors, data acquisition systems and geotechnical instrumentation. Each tutorial in this series will teach you a specific topic of common measurement applications by explaining. Strain gages may also be used to measure dynamic strain due to transient events or vibration. Strain gage measurements provide a means to determine the strain, stress and load on machinery components. Strain gauge, device for measuring the changes in distances between points in solid bodies that occur when the body is deformed. Measurements provided are in microstrain which is the ratio of the strain measured by the instrument at its measuring base.
This tutorial is part of the national instruments measurement fundamentals series. Manometers can measure absolute, gauge, and differential pressure. Therefore, if we replace r4 in figure 3 with an active strain gauge, any changes in the strain gauge resistance will unbalance the bridge and produce a nonzero output voltage. Strain gauge measurement using signal generator strain. Students will take measurements from and calibrate a strain gage mounted on a cantilever beam and placed in a quarterbridge wheatstone configuration. The configurations that strain gauges can be used in are, quarter bridge is the most common strain gauge configuration. Strain gage measurement with usb data acquisition hardware. Most strain gage measuring solutions provide an option to measure quarter, half, and fullbridge configurations. Mtis 1510a portable signal generator offers a simple method for monitoring the accuracy of these strain gauge meters. If the nominal resistance of the strain gauge is designated as rg, then the straininduced change in resistance. The most widely used gauge, however, is the bonded metallic strain gauge. Strain gages may be used to measure static strain due to relatively constant loads such as pressure or thermal expansion. National instruments has software options for quickly logging data to disk as well as for full programming.
For this example use national instruments compactdaq chassis ni cdaq 9178 and module ni 9219 with id cdaq1mod7. Strain gaugeload cell and how to use them to measure weight duration. Strain gauges wiring ni community national instruments. Learn how to install the lb11 cylindrical strain gauge. Connecting strain gages to a daq device national instruments. Data acquisition using labview nxg national instruments. Measure pressure using silicon piezoresistive pressure sensor pressure is defined as a force per unit area and the u tube manometer is traditionally used to measure it. Measure pressure using silicon piezoresistive pressure. A strain gauge also spelled strain gage is a device used to measure strain on an object. Consider an example, shown below in figure 1, of an ni compactdaq system with an ni 9237 fourchannel simultaneous bridge module.
Stress is defined as the objects internal resisting forces, and. Measurements using the airfoil, flat plate, and cylinder with the flow bench duration. Strain gages are configured in wheatstone bridge circuits to detect small changes in resistance. With ni modular hardware and flexible software, you can create a strain measurement system that meets the specific and unique needs of your application. Strain gauges, to be spot welded or embedded in concrete, are used for the measurement of strains caused by force applied strain to concrete, iron beams, reinforcement cages, piles and other. Our ivi drivers also fully support national instruments switch executive and all of our pxi switch modules can be accessed from agilent vee. Acquire data from strain gauges in labview nxg youtube. Measure up to 128 strain gauges, balanced bridges like pressure transducers or voltages over usb. Our combined experience means that our equipment can be easily adapted to provide unique solutions to electronic and geotechnical. Strain gage related instruction manuals can be downloaded. This document provides stepbystep instructions for wiring and configuring your daq device for strain gage measurements. The strain gauge is a classic example of a piezoresistive element, a typical strain gauge element shown here on the tip of my finger.
Stress is a force exerted on an object, while strain is the deformation an object undergoes under. When configuring the strain measurement task in software, you will need to select quarter bridge ii in the task set up. Those sensors have 3 wires red, white, black picture 1. As can be seen in figure 4 it is actually a three wire configuration. Every data acquisition task has its own special challenges. You can measure strain with a strain gage, which is a device with electrical resistance that varies in proportion to the amount of strain in the device, and with signal conditioning. When external forces are applied to a stationary object, stress and strain are the result. Each tutorial in this series will teach you a specific topic of common measurement applications by explaining theoretical concepts and providing practical examples. Measurements i 12 bridge strain gauge labview tutorial youtube. The media on which you receive national instruments software are warranted not. When using a strain gage, you bond the strain gage to the device under test, apply force, and measure the strain by detecting changes in resistance. Ruge in 1938, the most common type of strain gauge consists of an insulating flexible backing which supports a metallic foil pattern. Whatever your application, mobile or stationary, on a test cell or under extreme environmental conditions, hbm has the right measurement data acquisition system for your needs.
Strain gauge sensors or piezoresistive sensors piezoresistive means pressuresensitive resistance, or a resistance that changes value with applied pressure. Strain gauges are used either to obtain information from which stresses internal forces in bodies can be calculated or to act as indicating elements on devices for. Explore the fundamentals of data acquisition using sensors, ni data acquisition hardware, and labview nxg. Most strain gages measure changes in electrical resistance that occur when an object undergoes strain. Strain gage measurement strain gage installation simutech.
Strain gages are fundamental sensing devices that function as the building blocks of many other. If a true stress is ignored, the cost of not acting is usually far higher than the cost of dealing with the problem earlier. Measurements i 12 bridge strain gauge labview tutorial. Connecting strain gauges and shunt resistors to the ni. Hbm offers a wide range of strain gauges for a variety of applications. Micromeasurements complete portfolio of highperformance stress analysis strain gages deliver strain data you can count on and help you find practical solutions to prevent potentially catastrophic events. Use the nidaqmx driver to measure, generate, and synchronize data acquisition tasks.
Pcbased data acquisition and logger products can be applied to monitor, record and analyze a. Several of hbms data acquisition systems provide easytouse interfaces when used with the labview software. Measures bridgebased sensors, such as strain gages and load cells, in rugged environments. With ni modular hardware and flexible software, you can create a strain measurement system that. Fielddaq devices are dust and waterresistant and offer tsn technology for simplified distribution. Nov 04, 2014 overview this tutorial is part of the national instruments measurement fundamentals series. For this example use national instruments compactdaq chassis ni cdaq9178 and module ni 9219 with id cdaq1mod7. R 1 and r 2 compose one voltage divider circuit, and r 4 and r 3 compose the second voltage divider circuit. You can also set a zero reference level and monitor changes relative. Watch this video for a brief overview of some of the great tools this software offers.
This tutorial introduces and explains the concepts and techniques of measuring strain with strain. Oct 28, 20 overview this tutorial is part of the national instruments measurement fundamentals series. Use the finder tool to view a refined list of strain gages with only the specifications you need. Pickering offers comprehensive software drivers for windows, labwindows cvi and labview. Itm is a recognized national instruments gold alliance partner. The metallic strain gauge consists of a very fine wire or, more commonly, metallic foil arranged in a grid pattern. Open labview by doubleclicking the ni labview link on the desktop or navigating to startall programsnational instrumentslabview 8. Measures bridgebased sensors, such as strain gages and load cells, in pxi systems. How to choose strain gagebased transducers for pcbased data acquisition applications. Software drivers and downloads pickering interfaces. When used with a notebook, the emant300 usb 24 bit daq data acquisition module becomes a low cost portable, batteryoperated instrument which can be configured as a six channel strain indicator and recorder.
The media on which you receive national instruments software are warranted not to fail to execute programming. Learn the basics of hardware selection, including resolution and sample rate, and the foundation of sensor connectivity, including grounding and wiring configurations. How to choose strain gagebased transducers for pcbased. Hi, we have bought a chassis national instrument, a module ni 9237 strain gauge measurement with a dsub. To set up one of these configurations, please click on one of the below options. Hello everyone and i thank everybody that help others with their knowledge. Strain gauge working principle instrumentation tools. If the nominal resistance of the strain gauge is designated as rg, then the strain induced change in resistance. I have to attach a strain gauge on a aluminum tube to measure 3d forces on it. The wheatstone bridge is the electrical equivalent of two parallel voltage divider circuits. Refer to the installing labview and nidaqmx document for more information. Strain gauge instruments a variety of instruments for use in strain related applications, from dataloggers, bridges and amplifiers to full systems. Before you begin using your ni daq hardware, you must install your application development environment and nidaqmx driver software. Foil type strain gauges are small, low mass, and low in cost.
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