Read LVDT Calibration Procedure text version

Linear Variable Displacement Transducer (LVDT) Calibration Procedure By Javier Ubilla Rensselaer Polytechnic Institute

-

The main components of the LVDT are the Body, the Core and the Rod.

Body

Core

Rod

-

Estimate the maximum displacement expected to be measured during the test. According to this estimation select a LVDT Range and Core Length from the following table: LVDT Model Schaevitz 050 MHR Schaevitz 250 MHR Schaevitz 500 MHR Schaevitz 1000 MHR LVDT Range 0.1 in 0.5 in 1 in 2 in Core Length 0.5 in 1.12 in 2 in 3 in

-

For more information about this models of LVDT visit http://www.schaevitz.com/ Connect the LVDT to the National Instruments Data Acquisition System (DAQ), using the Modulus SCXI-1540 and the Accessory SCXI-1315. Input an Initial Calibration Factor (ICF) in the DAQ software. This initial factor should be close to the Actual Calibration Factor (ACF). Depending on the range of the LVDT the recommended ICF to get a measurement in [mm] are: LVDT Model Schaevitz 050 MHR Schaevitz 250 MHR Schaevitz 500 MHR Schaevitz 1000 MHR LVDT Range 0.1 in 0.5 in 1 in 2 in Recommended ICF 100 65 60 27

-

-

Move the core along the body of the LVDT and monitor the output in the DAQ software to make sure that the sensor is working properly. Mount the LVDT in the calibration device as shown in the figure at the same time that the output of the sensor is being monitored in the DAQ software.

-

-

Initially position the LVDT in such a way that the whole range of the LVDT is available for displacement in the calibration device. In the calibration device push ABS/INC to zero the initial reading. Make sure that the units displayed on the screen of the calibration device are in [mm]. Move the calibration device a distance D covering the whole range of the LVDT, at the same time record the change in the output reading in the DAQ, d. In the process of moving the calibration device from 0 to D stop at least 4 times in intermediate points Dintermediate and record the associated displacement at those intermediate points dintermediate from the DAQ. Calculate the ACF according to the following equation.

ACF = ICF d D

-

-

-

Plot the values Dintermediate versus dintermediate and check that the relation is nearly perfectly linear within the range of the sensor. Replace the ICF with the ACF in the DAQ software and repeat the procedure comparing the displacement recorded in the DAQ, d, with the displacement measured in the calibration device, D. Make sure to move the calibration device

-

along the whole range of the LVDT and make at least 3 comparisons calculating the error in the measurement, if the error is more that 1% repeat the procedure. Save the ACF. This ACF is only valid for the pair Body-Core of the LVDT selected. If for some reason there is uncertainty of what Core corresponds to what Body it is recommended to repeat the calibration procedure.

Information

LVDT Calibration Procedure

3 pages

Find more like this

Report File (DMCA)

Our content is added by our users. We aim to remove reported files within 1 working day. Please use this link to notify us:

Report this file as copyright or inappropriate

851697


You might also be interested in

BETA
LVDT Calibration Procedure