Vibrating Wire Strain Gauges
Contents
1. VIBRATING WIRE AND RESISTIVE STRAIN GAUGES User Manual Vibrating Wire and Resistive Strain Gauges INDEX Introduction Pag 4 Description Pag 4 Preliminary checks Pag 6 Installation Pag 6 Taking measurements Pag 8 Data management Pag 9 Troubleshooting Pag 10 Maintenance Pag 10 Appendix 1 Pag 11 Information contained herein are property of SISGEO S r l This document is subject to change without notification and is subject to be returned upon request No part of this User s Manual may be reproduced in any form without SISGEO s S r l written permission SISGEO S r l Vibrating wire and resistive strain gauges EN 00 12 Page 2 of 11 Notes on the use of product Symbols Identification SISGEO S r l Vibrating Wire and Resistive Strain Gauges For a safe and efficient use of the instrument please read carefully the following instructions before starting any operation Any use of the instrument other then the one described in this manual shall be considered at user s full responsibility The same applies for any unauthorized modifications In addition to the hereby listed standards the user must comply with the provisions of the current legislation on the matter of personal safety and health of persons in the workplace SISGEO is not responsible for any trouble breakdowns accidents etc due to the lack of knowledge and or confidence or non compliance with with the requirements contained i2. engineering reading Lee electric reading S sensitivity factor obtained from Compliance Certificate Vibrating wire and resistive strain gauges EN 00 12 Pagina 9 di 11 Vibrating Wire and Resistive Strain Gauges Troubleshooting Vibrating wire strain gauges Problem Possible cause Solution Cable shield not connected Connect er shield Electromagnetic fields generated by r and remove the cause Measure not engines generators antennas Shield the signal cable stable welders or high voltage lines nearb Insulation loss FE Grounding not well done Provide efficient Cable cut or damaged Repair the cable cable splicing kit is Measure the resistance between the available at SISGEO Wire not red and black conductors detected Acceptable values 1602 10 Consider cable length Resistive strain gauges Unstable Uncorrect wiring Make proper wiring measure OmA Se Cable cut or damaged Repair the cable verrange measure Cable splicing kit available at SISGEO Maintenance After sales assistance for calibrations maintenance and repairs is performed by SISGEO s service department The authorization of shipment shall be activated by RMA Return Manufacturer Authorization Fill in the RMA module clicking on http www sisgeo com en assistance repairs Send back the instrument equipment with the complete accessories using suitable packaging or even better the original o
3. integral with the constructions to be monitored they change the electric signal according to the strains Strain gauges can be vibrating wire VW or resistive VIBRATING WIRE STRAIN GAUGES They consist in a hollow cylindrical body with an internal steel wire stretched between the two ends Outside a resin cover protects the coil An internal thermistor allows temperature measurement VW strain gauges can be 1 Embedment VW Strain Gauges nominal range 1500ue Embedment VW strain gauges 3D strain gauge assembly 2 Arc Weldable VW Strain Gauges nominal range 1500ue Fully assembled arc weldable vw strain gauges Mounting blocks Strain gauge Mounting jig 3 Embedment VW Strain Gauges for Shotcrete nominal range 5000uE Vibrating wire and resistive strain gauges EN 00 12 Pagina 4 di 11 Vibrating Wire and Resistive Strain Gauges 4 No Stress VW Embedment Strain Gauge nominal range 1500ue They are assembled in an ABS box and embedded in concrete Since it will not deformed it is used with other strain gauges for thermic compensation 5 Vibrating Wire Rebars nominal range 1500uE RESISTIVE STRAIN GAUGES Resistive strain gauges consist in a squared section steel rod with 4 extensometers connected in Wheatstone bridge configuration They have electric signal 4 20 mA current loop V V and V Nominal range is 1500ue Resistive strain gauges can be for CLS embedm
4. ck GND Voltage signal V Yellow Out White Out SISGEO S r l Vibrating wire and resistive strain gauges EN 00 12 Pagina 8 di 11 Data management SISGEO S r l Vibrating Wire and Resistive Strain Gauges For automatic measures connect the instrument to a datalogger To obtain reliable measures with 4 20mA instruments we recommend a warm up time not less than 10 seconds VIBRATING WIRE STRAIN GAUGES SISGEO readout provide the deformation measure directly in ue Conversion is based on the following equation ue f x10 xG where f is the wire vibration sequence in Hertz G is the gauge factor that can be obtained from the Compliance Certificate Note f x 107 is also named Digit G nominal values for the main models are e OVK4100VS00 0 391 e OVK4000VSO00 4 043 e OVK4200VC00 3 814 The exercise readings refer to the initial zero reading Aus Li Lo Lo zero reading HE Li exercise reading H Zero reading shall be taken carefully once the installation is performed and the instrument is in operating conditions Temperature reading SISGEO readout display the temperature directly in C If the thermistor resistance value is taken please use the conversion formula in Appendix 1 RESISTIVE STRAIN GAUGES With the resistive strain gauges the following formula allows to convert the electric measurements into engineering values Ling Lee S HE Ling
5. ent or arc weldable The instrument is supplied with two discs 1 screwed at the ends ready for the use A pair of optional mounting blocks 2 can be assembled instead of discs for the welding on metal structures amp SISGEO S r l Vibrating wire and resistive strain gauges EN 00 12 Pagina 5 di 11 Vibrating Wire and Resistive Strain Gauges Preliminary Before starting the installation we recommend to check the instrument connecting checks to a portable readout see Taking Measurements Useful tools e Allen key SW3 e iron tie for embedment type e welder for weldable type Installation Embedment Strain Gauges For the installation proceed as follows e Tie the strain gauges on the rebar so they won t move during the grouting e With the vibrating wire model tie lightly over the black sheath in order to protect the cylinder body e Pay attention through the grouting in order to avoid damaging the strain gauges e For the 3D assembly block the strain gauges on the mounting block with the supplied screws Installation examples SM UU a FORA IH L a a VW OP i X l HAN L ras I a5 ny HLR Wa Ei ML AN b u LIG SISGEO S r l Vibrating wire and resistive strain gauges EN 00 12 Pagina 6 di 11 Vibrating Wire and Resistive Strain Gauges Arc weldable strain qauges To install please proceed as follows Insert the mounting jig in the Tighten the first scr
6. ew Proceed with the remaining mounting blocks screws until the mounting jig is blocked Clean the surface and weld Once the monting blocks are Insert the strain gauge and the mounting blocks cold remove the mounting block it with the screws jig Connect the strain gauge to the readout and check that the value is approximately 2500uE 10 The strain gauge can be adjusted unscrewing the screws on the open mounting block once adjusted tighten the screws The strain gauge has a nominal range of 1000 4000ue Do not exceed this values to avoid damaging it irreparably Installation examples SISGEO S r l Vibrating wire and resistive strain gauges EN 00 12 Pagina 7 di 11 Vibrating Wire and Resistive Strain Gauges Arc weldable resistive strain gauges To install proceed as follows b Pei Remove terminal discs Assemble the mounting blocks on the strain gauge Clean the surface and weld the mounting blocks in the chosen position During the welding we recommend to protect the strain gauge and the cable with a wet rag to avoid heath damaging If necessary apply anti rust paint on the weldings Taking Manual readings are taken connecting the conductors to a readout according to the measurements following scheme 4 20 mA current Ioop Red Loop sl VW VW strain gauges Vcc strain gauges Blue Sensing ratiometric signal V V Green Sensing Yellow Out White Out Vcc Strain gauges Bla
7. n this manual Check that the instrument has not been damaged during the transport Verify that the package includes all items as well as any requested optional accessories if anything is missing please promptly contact the manufacturer The user must strictly follow all the operations described in this manual Maintenance or repair of the instrument is allowed only to authorized operators These operators must be physically and intellectually suitable For information about instrument or order spare parts request please always specify data written on the identification label when replacing parts always use ORIGINAL SPARE PARTS The manufacturer reserves the right to make changes without prior notice for any technical or commercial requests We ll try anyway to keep the manuals updated in order to reflect product s revisions updates This symbol will be used used to catch reader s attention on the manual Pay special attention to the following instruction Instruments can be identified From a production lot number written on the Compliance Certificate From a serial number s n engraved indelibly on the instrument From a label on the instrument From a label on the cable Vibrating wire and resistive strain gauges EN 00 12 Page 3 of 11 Introduction Description SISGEO S r l Vibrating Wire and Resistive Strain Gauges Strain gauges measures strain in steel concrete or reinforced concrete structures Once
8. nes The shipping costs shall be covered by the sender Please return to the following address with suitable delivery document SISGEO S r l Via F Serpero 4 F1 20060 MASATE MI On the delivery document is mandatory to indicate the RMA code received Technical assistance e mail assistance sisgeo com Vv y gt gt gt 4 SISGEO S r l Vibrating wire and resistive strain gauges EN 00 12 Pagina 10 di 11 Vibrating Wire and Resistive Strain Gauges Appendix 1 THERMISTOR TEMPERATURE CONVERSION Resistance to temperature equation 1 A B LnR C LnR 273 2 Where T temperature in C LnR natural Log of the thermistor resistance A 1 4051x10 coefficents calculated over the 50 to 70 C span B 2 369x10 C 1 019x10 SISGEO S r l Vibrating wire and resistive strain gauges EN 00 12 Pagina 11 di 11
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