Pressure&Force Help en 2014.07.08.

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Pressure & Force 3Labview measurement program for multi-channel

pressure, force and hotwire measurements, synchronizedwith a probe positioning traverse

Márton BalczóTranslated by sztella Balla

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HELP

Labview library Version Content

Pressure&force.llb 3.37 measurement program and its routines

Transducer_calibration.llb 4.32 routines performing linear transducercalibration, one component hotwirecalibration and the matrix calibration ofmulti-component force measurementsystems

isel_ui4.x.llb 1.21 interface program of the isel motioncontroller

PointEditor.llb 0.19 measurement point file editor

ARA_Joystick.llb 0.1 joystick controller routinesARA_Utils.llb, 1.06 common routines

Date: 8 July 2014


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Pressure & Force HELP 4/37

In the File menu the main measurement file can be opened, saved or a newfile can be created. To keep the settings it is advisable to save the formermeasurement file, then delete the measurement lines in it and save it with a

new name. Thus there is no need to edit the settings one more time.

Main window

At the top of the main window the measurement control buttons are located,beyond them the measurement data and the settings can be found on the tabsof a Tab Control. Proceeding from left to right we begin with the settings andend up with the results.

Initial settings - Settings tab

The settings of this tab will appear in the main measurement file's header. To

apply the settings of the field on the left side click on the Apply settings button. The current settings can be seen in the table on the right side.

Note: after the first click on the Apply settings button the programwould like to save the file on the hard disk drive, and will ask where tosave it.

The measurement settings stored in the file:

• Measurement time : the time of the measurement can be chosen byclicking on the clock button

• Measurement name • Personnel • Header comment: the description of the measurement in one line• Barometric pressure [Pa]: barometric pressure during the

measurement: it can be given or retrieved from the Settings menu• Temperature [C]: temperature during the measurement: it can be

given or retrieved from the Settings menu• Read barometric pressure at each measurement: after each

measurement it retrieves the atmospheric pressure from theDatasocket URL given in the Settings menu ( Barometric pressureand temperature... ) and stores it in the main measurement file'scurrent measurement line

• Read temperature at each measurement: after each measurement itretrieves the temperature from the Datasocket URL given in theSettings menu ( Barometric pressure and temperature... ) and storesit in the main measurement file's current measurement line

• Use temperature correction (hot-wire): in case of hot-wire (CTA)measurements it reads the temperature source given in the Settingsmenu ( Barometric pressure and temperature... ) and after each

measurement corrects the calculated velocity values.• Save time-resolved data: Shall the time-resolved data be saved inseparate files? It is recommended to save them because this way fromthe measured values e.g. a FFT can be made subsequently.


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Measurement "ile tab

In the table of this tab the measurement results can be seen line by line. Thecolumns are:

• Meas. point name: the name of the measurement, expediently it is a

number• Comment : short comment in a line• X, Y, Z [mm]: current position of the traverse• mérési adatok oszlopai (1-4) x a csatornák száma: a

csatornabeállításoktól függ ő en tartalmazhatják a mértátlagfeszültséget, az abból számolt átlag fizikai mennyiséget, illetveezek RMS-ét (Root Mean Square Error) the columns of themeasurement data (1-4) x is the number of channels: depending on thechannel settings they can contain the measured average voltage andthe average physical quantity calculated from it, and also the RMS(Root Mean Square Error) of these.

• p0: barometric pressure, if we have chosen to read the barometricpressure at each measurement

• T0: temperature, if we have chosen to read the temperature at each

measurement• name of the data file, if we have activated the "save time resolveddata" setting

After selecting a line, the Name and Comment fields can be modified withthe Add comment & name button. The lines can be deleted using the Deleteline button. Multiple lines can be selected by pressing the Shift button.

Note: If the Save file after each measurement option (at the bottom ofthe Measurement settings tab) is switched on, then the program will add(save to the hard drive disk) the new line to the measurement file aftereach measurement so that in case of a crash the important measurementdata will not get lost. The changes made on the header of themeasurement file or on the Name and Comment fields of themeasurement lines are only stored in the memory. Therefore at the endof the measurement series it is recommended to save the mainmeasurement file one more time, for example by overwriting the originalmeasurement file.

Shifting between the completed measurements

Shifting between the measurements is possible by selecting a measurementline or by using the arrows on the right side above the Tab Control. If we

have saved the time data, the program will load them, calculate the average,display it on the Actual channel data tab, and on demand display the FFT aswell.


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#ctual channel data tab

For the continuous and immediate display of the measured physical quantitiesthe Show actual channel data button can be used. On the left side of theActual channel tab the current values of the measured quantities (calculatedpressure, force, etc.) can be seen.

From the Show actual channel drop-down menu we can choose the channelwhose graph we would like to display in the diagram to the right. Byactivating the Large display in separate window setting the current value ofthe channel selected from the list will appear in a large window.

Note: We have to select the channels which should be displayed in thelarge window before starting the measurement. The large displaywindow can be closed or opened during the measurement by untickingor ticking the box of the Large display in separate window setting.

ime resol!ed data tab

On this tab the measurement data of the Single measurement or the automaticmeasurement can be seen. We can zoom with the bottom in the bottom rightcorner, the Autoscale can be turned on/off by right-clicking on the axes. Witha right-click on the diagram the simplified image of the diagram can be savedto a .jpg, .wmf, .bmp file.

FF tab

On this tab the Fourier transform of the measured data can be generated, with

various window functions, sample size, number of averages. The diagram canbe customized as shown in the case of the Time resolved data tab.


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• With the Recalculate FFT button the FFT can be recalculated withthe modified parameters.

• With the Save FFT... button the FFT graph can be saved to a text file,separated with Tabs.

$hannel settings

The channel settings editor window can be reached by clicking on theChannel settings... button on the Measurement settings tab. Here:

• The lines of the table at the top can be modified by selecting (one ormultiple, by pressing the Shift button) them. The settings of theselected channels appear in the cluster under the table, themodifications can be made here.

• With the Load and Save buttons the channel settings can be loadedand saved to a file with a .chs extension. Saving the file is necessary,because the main measurement file refers to the .chs file.

• The dialog box can be closed with the OK and Cancel buttons.

• We can select the channels from which we want to acquire data. ( Editmeasurement channels... button). From the drop-down menu on theleft side of the dialog box the DAQmx global channels that havealready been defined can be selected or new ones can be created. Theorder of the channel list can also be changed.


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Features accessible "rom the menu

Setting the atmospheric pressure and temperature

The atmospheric pressure and temperature values are necessary for thecalculation of the flow velocity from dynamic pressure. These can be set inthe Barometric pressure & temperature menu item of the Settings menu.

The settings can be given:

• manually• by retrieving the data from a thermometer or a digital barometer

connected to another computer which is accessible through thenetwork. The data can be retrieved by giving the so-called DataSocketlink of the instrument and pressing the Test channel button. After 1-2seconds the measured value appears, or an error message if the datacould not be retrieved.

• Barometer: dstp://152.66.21.31/setra470• Big windtunnel thermometer (yellow):

dstp://152.66.21.31/GMH3710• Laboratory thermometer (blue): dstp://152.66.21.31/GMH3530

Note: the GMH 3530 thermometer can be connected to the computerwith which the measurement is carried out, e.g. if we want to measurethe temperature of the flowing air inside our device. In this case the NIDataSocket Server and the GMH3710.llb driver have to be started. Theprogram gives the current DataSocket URL, which can be given in thedialog box seen above.

The current values can be seen in the upper right corner of the main window,and can be updated using the Update env. data button.

$alibration

The calibration of the linear transducer can be made in the Linear

transducer calibration... item of the Setting menu. The one componenthotwire calibration can be found in the 1-D hotwire calibration... item of theSettings menu. The matrix calibration of multicomponent force measurementsystems can be made in the Multi-component balance calibration... menuitem. The detailed description of these can be found in the help of theTransducer_calibration.llb. (It can be openedwith the Help button of eachdialog box.)

ra!erse settings

1 to 3-axis, ISEL type motion controllers can be used for the automatictraverse movement performed by the Pressure & Force program. The settingsof the controllers (initialization, change of the coordinate system, manualmotion etc.) can be made in the Traverse settings item of the menu. Thedetailed description of the motion controller can be found in the help of the

isel_UI4.x.llb.


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Note: An automatic measurement cannot be started without theinitialization of the traverse!

%pdate time-resol!ed data paths

With this function of the Tools menu the place of the dataset file referred inthe lines of the given measurement file can be modified. Since these areabsolute references, when copying the program to a new computer or adifferent hard disk drive, the program would not find the datasets. On theUpdate time-resolved data paths... panel the references in selected lines orin all lines can be set to a new time data directory.

With the Update measurement file header option the directory in the headerof the measurement file can also be modified, i.e. the time data of new

measurements will also appear in the new directory.

Note: To save the modification of the main measurement file to the harddisk drive, the file has to be saved with the Save measurement... !

$on!ert time-resol!ed data

The time-resolved data of the completed measurements can be convertedbetween 3 formats with the help of this panel. The following can beconverted:

• the lines selected in the main measurement file• all lines• files selected from the file browser window.

The original files can be overwritten or the new files can be copied to anotherdirectory. In the latter case the references of the main measurement file canbe redirected with the update measurement file links option.

With the update measurement file header option the general settings of thetime-resolved data can be set to a new format or to a new position in the file's

header.


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Note: To save the modification of the main measurement file to the hard

disk drive, the file has to be saved with the Save measurement... !

'ther (I-s) Lab(IE* technical in"ormation

pressure&force-main.VI hierarchy:


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ransducer calibration•

Data • Introduction • Starting the program

o Independent run o In case of a version built into another measurement program

• Linear transducer calibration o Calibration mode o Measurement mode o Diagram and error bar settings

• Hotwire calibration o Introduction o Temperature compensation o Use of the program o Calibration mode o Hotwire calibration with measurement in single points o Curve fitting o Hotwire calibration with blow down method o Advanced tab

• Matrix calibration for multiple load cell balances o Introduction o Use of the program o The panel on the left o Lower control buttons

o Settings tab o Voltages tab o Calculate matrix tab o Loading recalculated tab o Graph, 3D Graph tab

• Other VI-s, LabVIEW technical information

Data

Name of Labview library: Transducer_calibration.llb

Version descriptions: Transducer_calibration_versions.txt

Required for running the program: ARA_Utils.llb

Note: The current version's name always includes the version number (e.g.Transducer_calibration_v4.15.llb). To use it in other programs (ARA-LDA.llb, Pressure&Force.llb) the version number has to be removed from thefile name (Transducer_calibration.llb) and the file has to be copied to thesubdirectory where the program is.

Introduction

For fluid mechanical measurements numerous measurement devices are usedwhich have analog voltage signal output, e.g. pressure transducer, load cell,hotwire probe. Most of these have linear characteristics, i.e. there is a linear

relation between the measured physical quantity and the voltage, e.g. in thecase of pressure:

p[Pa] = slope * U[V] + zero

where slope and zero are the constants of the calibration curve.


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In the Channel list editor the measurement channels can be selected for themeasurement. After closing the panel the physical quantities measured withthe reference device can be seen in the first column of the table on the left, inthe following columns the measured voltage values (in [V]) of each channelcan be found.

In calibration mode after setting the channels, the voltage measurements can

be carried out by pressing the Measure button. The sampling time and thesampling frequency can be modified. The results of the measurement appearin the table. The physical quantity measured with the reference device can be

added to the chosen line with the Add reference value command. The wrongmeasurement can be deleted with the Delete line command.

The curve fitting happens automatically after each measurement. Thecalibration curve of a specific channel can be selected in the Show channelgraph drop-down menu under the diagram on the right. If required the curvefitting and drawing can be repeated with the Redraw button.

With the Show error graph option the difference from the calibration curvecan be shown, here the X axis coincides with the calibration curve, the errorbars are horizontal lines. With this diagram any outstanding differences can

be identified, and in measurement mode it can also be seen if the verifyingmeasurements are within the error bar.

The data of the channel selected in the Show channel graph drop-downmenu can be seen in the blue box under the diagram. The date of thecalibration and the ID of the transducer is set here manually! If required, theconstants can also be edited.

Before finishing the calibration the calibration files have to be saved with theSave to file... command. The program offers the channelname .txt file name.

Measurement mode

Initially the program is in measurement mode. If we have not done it already,the channels through which we want to measure should be selected in the

Channel list editor . Using the Open file... button the calibration files can beopened. Here, a calibration file can be assigned to each channel by selectingthe line and pressing the Add button.


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The loaded calibration curves appear in the diagram on the right, and in theblue bordered box under it. If it is needed the Show channel graph drop-down menu and the Redraw button can be used.

Control measurements can be made with the Measure button. The differencebetween the calibration curve and the control measurement can be zeroedwith the Zero channels with selected line button. Prior to this a line has to beselected from the table to which we want to fit the calibration curve.

The modified calibration can be saved with the Save to file... command. It isadvisable to simply overwrite the existing calibration file.

Diagram and error bar settings

• Zooming and shifting is possible with the 3 gray buttons under the

diagram.• By right-clicking on the axes the autoscale can be turned on/off andthe axis can be formated.

• The appearance of the points and curves can be changed by right-clicking on the legend.

• With the Show error graph option the error of the curve fitting canbe shown.

• In the Error bar settings box we can set the error type which should bedisplayed:

• The mean error of the curve fitting• The maximum error of the curve fitting• An absolute error value (fix error value, can be set manually, for

example it can be the measurement error given in the specification ofthe device, e.g. +/- 5 Pa)

• Absolute error value given in the percentage of a measurement value(e.g. the measuring range of the device)

Hotwire calibration

Introduction

In hotwire anemometry (Constant Temperature Anemometry) the hotwire(CTA-) sensor is connected to a measuring bridge. The measuring bridgeconverts the resistance change caused by the change of the flow velocity atthe sensor to a voltage change, so on the output of the bridge we can measurea voltage value dependent on the flow velocity. However the relation is non-linear, it can be described with a third or higher order polynomial or with theso-called King's law:

U[V] = (A * v [m/s] ^n + B )^0.5


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where A, B and n are the constants of the calibration curve. In case ofpolynomial fitting the Ai constants of the polynomial are sought:

v [m/s] = A0 + A1 * U[V] + A2 * U[V]^2 + A3 * U[V]^3 + ... + An *U[V]^n

Knowing the constants - similarly to the sensors with linear characteristics -the flow velocity can be determined from the voltage signal.

The flow with known velocity can be created

• in a wind tunnel (another measurement device is put next to thehotwire sensor, for example a Laser Doppler Anemometer with whichthe velocity is measured directly or a Prandtl tube, in this case thevelocity of the fluid can be calculated from the measured dynamicpressure).

• with a calibrator, which is in fact a miniature blow-down wind tunnel,the air's velocity at the outflow of the nozzle can be calculated fromthe Bernoulli equation from the difference between the measuredpressure in the first cross section and the atmospheric pressure.

emperature compensation

In contrast to most of the pressure transducers and load cells, the CTAsystems are not temperature compensated, i.e. the temperature change of theflowing fluid causes error in the measurement. Therefore the temperature of

the fluid has to be measured during the calibration and the measurement, anda corrected voltage signal (referring to the calibration temperature) can becalculated from the current voltage signal.

%se o" the program

The program has two operation modes:

• calibration mode: creating measurement points and automatic curvefitting

• measurement mode: verification of an existing (opened) calibrationcurve

$alibration mode

The calibration mode can be opened with the New calibration button and canbe exited using the End Calibration button. With the help of the Open file...

/ Save file... the calibration files with .htwcal extension can be loaded andstored.

The following settings have to be made on the Settings tab before starting the

calibration:

• Personnel, Date, Calibration comment .


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In the Iteration constants frame the type of the fitted curve can be selected(Curve fit type ), it also contains the results of the curve fitting iteration, theconstants and the difference between the points and the fitted curve in m/s(Mean error, max error ). The fitting is done by the Fit curve button.

In the Error bar settings frame the displayed error bars can be chosen. If theShow error graph is checked then the digram shows the difference of thepoints around the fitted curve, and not the fitted curve. If the Show bothcurve fits is checked then both curves (according to King's law and thepolynomial) are displayed. (The 'selected' curve is the one chosen in theCurve fit type . The curve fitting for both types has to be made beforehand!)

Hotwire calibration with blow down method

The DISA and Dantec hotwire calibrators are able to create not only aconstant velocity but also a uniformly decreasing velocity by decreasing theprimary pressure continuously (by the blow down of the primary air tank).With this method a measurement with large number of points can bereplaced, if the voltage of the hotwire and the reference pressure is measuredsimultaneously. (In case of a wind tunnel measurement the same can beachieved by continuously revving up the wind tunnel.)

The blow down calibration is available on the Blow down tab.

1. The data acquisition is started with the Measure blowdown button.2. The blow down begins after pressing the Scan button on the hotwire

calibrator, after some time the velocity decrease stops. If the


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calibration is done in a wind tunnel, then the velocity is set from 0 tothe maximum velocity continuously.

3. The measurement is stopped with the Stop blowdown button.4. In the upper diagram the time resolved data of the measured velocity

can be seen. We have to zoom to the region where the velocitychanges, which will be used for the calibration! (If necessary thezoom out and fit zoom functions can be used, which can be found onthe Zoom toolbar in the lower left corner of the diagram.)

5. The program displays the measured reference velocity - hotwirevoltage pairs on the lower diagram. These are quite noisy, thereforethese points can be averaged ( Number of data points ) and the

averaged points can be added to the table on the Calibration tab.6. On the diagram of the Curve fitting tab the new points appear afterpressing the Redraw button.

With the help of the zoom and Number of data points the blowdown pointscan be adjusted arbitrarily. If we do not like the added points, then they canbe deleted with the Delete selected line(s) button on the Calibration tab.

It is worth repeating the blow down at different states of the calibrator'sFLOW control, thus the points cover a wider velocity range.

#d!anced tab

• Iteration settings o Termination : the parameters of the curve fitting iteration

according to King's law can be set here.o Extrapolation limits : the fitted curve can be extended beyond

the calibration limits (min. and max. voltage).o Error out : error message of the iteration routine

• Velocity indicator moving average : the actual flow velocity valueshown on the Calibration tab is formed from the moving average ofthe current measurements. By increasing the length of the movingaverage, the fluctuation of the displayed value can be decreased.


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Matri+ calibration "or multiple load cell balances

Introduction

In case of systems that measure multiple force components it cannot beexcluded that the load of one of the components (e.g. vertical force) has aneffect on the load cell or strain gauge used for the measurement of anothercomponent (e.g. horizontal force). Therefore when determining the load, notonly the signal of the particular cell has to be considered, but also the signalsof all other cells.

ji E f F =

where F i is the force or torque component, E j is the voltage measured on thecells, j = 1 . . . n is the number of load cells.

The relation is nonlinear, therefore even a forth or fifth order fitting can benecessary. However the cells' effect on each other is not always considered in

higher order products.

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For example when measuring two force components with two cells, the thirdorder relation is:

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which is in a shorter form:

E K F ⋅=

where K is the calibration matrix, F is the force and torque vector, E is thevector of cell voltages' products with different orders. The number ofconstants in one line of the K matrix is: 2 n + ( n − 1 ) n 2 . From the tablebelow it can be seen that in case of 6 force and torque components there can

be about 200 constants.

Number of force and torquecomponents

The size of the calibration matrixlinear 2nd order 3rd order

2 2x2 2x5 2x73 3x3 3x9 3x124 4x4 4x14 4x18

5 5x5 5x20 5x256 6x6 6x27 6x33

Accordingly during the calibration the number of the recorded Load1,Load2,...load combinations have to exceed significantly the number ofconstants.

From the F and E vectors recorded during the calibration the followingequation system can be formed for every force component:


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In the Channel list editor the measurement channels can be selected onwhich we would like to measure. The Reset button deletes every formermeasurement data from the table.

With the help of Open file... / Save to file... the calibration files with .mcal extension can be loaded and saved. The files are in ASCII format. The arraysrecorded during the calibration can be saved to a text format separated byTabs, which can be easily loaded to Excel, using the Save Arrays button.

Lower control buttons

• Measure : measurement on the set channels. Prior to it the value of theload has to be set at the LOAD vector next to the buttons. (The orderof the values is the same as the order of the channels.)

• Delete line : deletes the selected measurement.• Zero Channels with selected line : assigns the selected measurement

line to the 0 load, the unloaded state of the force measurement system.The value is stored in the Zero Vector ( Calibration matrix tab )

• Add loading to selected line : updates the load values of the selectedmeasurement line to the value written in the LOAD vector.

• Calculate matrix : determines the calibration matrix on the basis ofthe load and voltage vectors (see Calibration matrix tab )

• Recalculate loading : using the calibration matrix it calculates theloads from the measured voltages. This can be compared with the loadarray, in which the actual loads were recorded. (See Loadingrecalculated tab) A calibration carried out earlier can also be checkedwith this operation. For this the calibration file has to be loaded,measurements have to be made with random load combinations andthe load has to be calculated from the voltages using the Recalculateloading button.

Settings tab

• On the upper part of the tab the constants of the calibration matrixbelonging to the set dimension and order can be seen.( Parameternames )

• In the middle the data of the calibration can be set: Balance ID,Personnel, Date, Reference unit, Calibration comment

• At the bottom the Sampling frequency and the sampling time of thecalibration measurement can be set, and the set channels can also beseen.

(oltages tab

Shows the set cell loads and the measured voltage value for each load. Theprecision of the display can be set with the Digits of precision variable.


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Loading recalculated tab

On the tab the load recalculated with the calibration matrix and the differencebetween the recalculated and measured values, i.e. the error of the calibrationcan be seen. By examining the latter the calibration are very much out ofplace can be detected. points which are very much out of place can bedetected. (The calibration can be corrected by deleting or remeasuring thesepoints.)

The root-mean-square error of the recalculation ( Recalculation RMSE ) andthe relative value of it, applied to the maximum load ( Recalculation relativeerror ) can be found under the tables.

,raph) 3D ,raph tab

On the two tabs the recorded calibration points and the calibration relationcan be displayed in 2D and 3D. The content of the axes can be modified(Graph axes ). For example the impact of one force component on the voltageof another cell (cross impact) can also be displayed.

The Redraw button refreshes the diagram.




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PointEditor measurement point mesheditor

• Introduction • Starting the program

o Independent run o In case of a version built into another measurement program

• Use o Main dialog panel

o Profile editor window • LabVIEW technical information

Name of Labview library: PointEditor.llbVersion descriptions: pointeditor_versions.txt

Required for running the program: -

Note: The current version's name always includes the version number (e.g.PointEditor_0.17.llb). To use it in other programs (ARA-LDA.llb,Pressure&Force.llb) the version number has to be removed from the filename (PointEditor.llb) and the file has to be copied to the subdirectory wherethe program is.

Introduction

By using the program, measurement point meshes, tables consisting of X, Y,Z point triplets can be generated, and saved to text files separated by Tabs.All these could be done by spreadsheet softwares, however the PointEditorhas multiple advantages:

• measurement point profiles can be created to arbitrary directions ofthe space

• non-homogeneous profiles can be created e.g. for boundary layermeasurement

• the profiles can be displayed in a diagram

Starting the program

Independent run

After clicking on the Pointeditor.llb a Labview window opens and thecontents of the library appear. In the front, there is the messraster_edit.vi , bydouble-clicking on it and pressing the Run button in the toolbar, the pointeditor starts.

In case o" a !ersion built into another measurement program

It can be reached after pressing the "Edit measurement points" or the "Pointeditor" button, or a similar one in the menu of the given program.

%se

Main dialog panel



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The measurement point mesh is a table consisting of X, Y, Z point triplets.This can be built up from one dimensional profiles. The profiles can begenerated in the profile editor window by pressing the New profile... button,or they can be loaded with the Load profile... button.

The loaded profiles can be seen in the profile names list on the left side, byclicking on them the diagram on the left displays the profile and the profilecoordinates in the list next to the diagram.

These loaded profiles can be placed to a given X, Y, Z reference point of thespace, to the given direction of the space (x+, x-, y+, y-, z+, z-). The profiles

can also be added obliquely, in this case two angles have to be given:1. the angle to axis (beta) and2. the angle around axis (alfa)

The definitions of the angles can be seen in the figures below, in case ofdirections x+, y+ and z+ :

With the Add profile to points command the profile is added to the givenreference point. With the Undo command the profile additions can bewithdrawn, with the Reset button the whole point mesh can be deleted.

Measurement point files with .pts extension (text files separated by Tabs) canbe loaded with the Load file... command and saved with the Save points... .

The finished point mesh can be displayed in two types of diagrams dependingon whether the 3D diagram box is selected or not:

• 2D diagram: the projection of the point mesh is seen. The projectionplane can be selected under the diagram (XY, XZ or YZ). Zooming,shifting etc. can be done by using the buttons under the diagram.

• 3D diagram: the point mesh is seen in space. The selection can bemoved on the diagram (the coordinates of the selected point is shown)

• Left click = rotate• Shift + left click = shift• Alt + left click = zoom

To exit the dialog panel use the OK or Cancel buttons.

Pro"ile editor window

One dimensional point series can be created here. After giving the minimumand maximum values, linear profiles with given distance between the pointsor with given number of points, exponential profiles or profiles with given



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distance growth rate can be generated by pressing the Generate profile button. The result can be seen in the frame on the left, with 3 decimal places.The point selected from the list on the left is displayed in the field at thebottom, where the serial number of the point within the profile (thenumbering begins with 0) also appears. The values can be modified manually,points can be deleted with the Delete point button, and further points can beadded with the Insert point button.

The profiles can be saved into text files separated by Tabs with .pr extension,and can also be loaded ( Save profile... , Open profile... ).

It is also possible to add a profile to another: by pressing the Add profile... button, another profile can be added from a file to the generated profile. Thepoints in the profile to be added and saved, can be put in order (the directionof the arrangement - ascending, descending - influences the order of themeasurement!), the points close to each other and the duplicates can beremoved.

Lab(IE* technical in"ormation

The hierarchy of the messraster_edit.VI:


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%se

The functions of the program are located on the tabs of a Tab Control, thesettings have to made from left to right. At the bottom of the window theerror feedback can be seen on the execution of the operation, a green tick andthe error code 0 indicates the error free execution of the command. In case ofposition request, the returned position can be seen in the source field inhexadecimal numbers.

Note: After the first start of the program only the first tab of the panelcan be seen, the other tabs are blocked so that the order of the starting is

kept.

Initial settings - Settings tab

The properties of the axes are indicated on the linear units, these have to bewritten into the Traverse Properties frame:

• velocity in step/sec. Generally one motor revolution is 360 steps,since the motors have 180 poles, but depending on the settings, theyturn one, half or a quarter pole on every step impulse. The advantageof the half and quarter step is the smaller vibration of the motor.

• how many steps are in a unit of displacement of the slide in the linearunit. It can be calculated from the pitch of the ball screw in the unitand the step/revolution.

• The length of the axis. It has to be given because the software "cuts"the motion to target positions outside of the length, i.e. it does notallow motion outside of the length of the axis by default.

To apply the settings the Apply settings button has to be pressed.

The settings above can be loaded and saved, they do not have to be alwaysgiven manually. The software always refreshes the content of the file, thus incase of a software crash the file with the .set extension can be loaded. If the

Save as a copy box is ticked, it saves the settings to a different file, but itcontinues to refresh the original.

Note: Besides the content of the Settings tab the .set files also storefurther settings, which can be set on other tabs, see the content of thecluster tab.


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$oordinate s/stems - $oordinate s/stem tab

The position stored by the motion controller is called hardware coordinatesystem ( Hardware coordinate system ). Its starting point is always at the endof the linear units, on the motor side, and it points towards the other end ofthe linear unit. However it is possible to use a so-called software coordinatesystem ( custom software coordinate system ). With this, the origin can beshifted arbitrarily and the direction of the axes can also be switched. Theapplied relation (conversion function):

X_custom = A * X_hardware + B

By pressing the software zero shifting button an arbitrarily given point ofthe new software coordinate system can be shifted to the current hardwareposition.

The functions of the new coordinate system can be modified manually on theright side of the tab. The conversion is done by the Set new coordinatesystem button.

Note: the change can only be made from hardware to software or fromsoftware to hardware coordinate system, it is not possible to switch froma software to another software. First the switch has to be made to thehardware and then to the new software.

In the upper right corner of the tab the current limits of the motion are shown,the endpoints of the axes in the applied coordinate system ( Coordinate systemlimits ).

Mo!ement - Mo!e tab



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Manual motion operations can be made on this panel. In the upper left cornerthe current coordinate system is shown.

• Ask position : retrieving the position, the last known position of the

traverse is shown in the fields.• Move (abs) : move to the given point of the coordinate system. The 0

and A buttons serve for zeroing and for taking the last requestedposition to the target coordinate fields.

• Move (rel) : move to a given distance from the current position. The 0button serves for the zeroing of the fields.

During every motion operation a small dialog box appears with a big STOPbutton. Therefore the motion can also be aborted from the software. Duringthe motion, the reading of the position does not work, thus the positionfeedback in this panel reports an error.

In the lower left corner, positions can be stored in a table ( Store ). Amovement can be made ( Move to ) to the position of the selected line, thewhole table can be saved or loaded ( Load... and Save... ) to a text fileseparated by Tabs.

On the right side of the tab the Stepper module is located, which helpsmaking small steps. Steps can be made to the given directions by pressing thecolored buttons. Small and large steps can be selected ( small step , large step ),they can be selected by using the slider switch, which is on the left side of thefields.

#utomatic mo!ement

On the Automatic tab more complex series of measurement points, profilesand meshes can be generated and tested. The Edit measurement points...

button opens the measurement point editor subprogram, another documentcontains its description.

After pressing the Test button the traverse goes through the point seriesselected in the measurement point editor.

Note: Be careful when starting the program, because it is not (yet)possible to stop the measurement program from the software. Only thehardware stop button can be used in case of emergency.



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Log "ile - Log tab

The moving software records every completed operation in a log file, whichcan be useful e.g. for troubleshooting. Its location can be given on theSettings tab, its content can be seen on the Log tab.



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The hierarchy of the options.VI:

The isel_ui4x_3.vi does the serial communication with the motion controller.

The Isel_UI4.x.llb contains further SubVI-s for the insertion of thepositioning traverse into other measurement programs. I can provide furtherinformation on these personally.

• Automatic_move.vi : a VI which can be called from the mainprogram, it moves to the given line of the given measurement pointfile

• FOPROG_PROBA.vi: an example of the building in of the traversesoftware into the main program

Pressure&Force Help en 2014.07.08.

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Transcript of Pressure&Force Help en 2014.07.08.