Waveform & FDS

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Waveform & Fast Data Sampling Option Getting Started Guide 1

Getting Started Guide

Revision BIssued February 2006

Waveform & Fast Data

Sampling Option


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Waveform & Fast Data Sampling Option Getting Started Guide2

©2003–2006 by TA Instruments—Waters LLC109 Lukens DriveNew Castle, DE 19720

Notices

The material contained in this manual, and in the online help for the software used to support this instru-

ment, is believed adequate for the intended use of the instrument. If the instrument or procedures are usedfor purposes other than those specified herein, confirmation of their suitability must be obtained from TAInstruments. Otherwise, TA Instruments does not guarantee any results and assumes no obligation orliability. TA Instruments also reserves the right to revise this document and to make changes without notice.

TA Instruments may have patents, patent applications, trademarks, copyrights, or other intellectual propertycovering subject matter in this document. Except as expressly provided in written license agreement from TAInstrument, the furnishing of this document does not give you any license to these patents, trademarks,copyrights, or other intellectual property.

TA Instruments Operating Software, as well as Module, Data Analysis, and Utility Software and their associ-ated manuals and online help, are proprietary and copyrighted by TA Instruments. Purchasers are granted alicense to use these software programs on the module and controller with which they were purchased. Theseprograms may not be duplicated by the purchaser without the prior written consent of TA Instruments. Eachlicensed program shall remain the exclusive property of TA Instruments, and no rights or licenses are grantedto the purchaser other than as specified above.


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Important: TA Instruments Manual Supplement

Please click on the links below to access important information supplemental to thisGetting Started Guide:

• TA Instruments Trademarks

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• Other Trademarks

• TA Instruments End-User License Agreement

• TA Instruments Offices

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Table of Contents

Important: TA Instruments Manual Supplement ..................................................................................................... 3

Table of Contents ............................................................................................................................................................ 4

Notes, Cautions, and Warnings .................................................................................................................................... 6

Chapter 1: Introducing the Waveform & Fast Data Sampling Option .............................................................. 7

Overview ......................................................................................................................................................................... 7Components ............................................................................................................................................................. 7

DAQ-Pad ........................................................................................................................................................... 7Software Components ..................................................................................................................................... 7

System Requirements ............................................................................................................................................. 8

Basic Steps for Operation .............................................................................................................................................. 9

Chapter 2: Installing & Configuring the Option ................................................................................................. 11

Installing the Unit ......................................................................................................................................................... 11Installation and Configuration ............................................................................................................................ 11Using the DAQConfig Utility .............................................................................................................................. 13

Chapter 3: RheoCorr External Correlator............................................................................................................... 15

Overview ....................................................................................................................................................................... 15

Introducing RheoCorr .................................................................................................................................................. 15Understanding the RheoCorr Fields & Buttons ................................................................................................ 16

RheoCorr Fields .............................................................................................................................................. 16RheoCorr Buttons .......................................................................................................................................... 17

Learning About the RheoCorr Plot Window ..................................................................................................... 18Setting Up the Plot Window ......................................................................................................................... 18Copying Correlation Buffer Into Orchestrator........................................................................................... 19Downloading Data Into Orchestrator ......................................................................................................... 19

External Trigger Control ....................................................................................................................................... 20Window................................................................................................................................................................... 20

Running RheoCorr in Local Mode ............................................................................................................................. 21Setting Up Correlation Parameters ..................................................................................................................... 21

Running RheoCorr with Orchestrator ....................................................................................................................... 23Additional Information on RheoCorr ................................................................................................................ 26How Data is Correlated ........................................................................................................................................ 26

Effect on Measurement Time ........................................................................................................................ 27

Chapter 4: RheoChart Strip-Chart Application .................................................................................................... 29

Overview ....................................................................................................................................................................... 29


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Introducing RheoChart ................................................................................................................................................ 29Understanding the RheoChart Fields & Buttons .............................................................................................. 30

RheoChart Fields ............................................................................................................................................ 30RheoChart Buttons ......................................................................................................................................... 30

Learning About the RheoChart Plot Window ................................................................................................... 32Setting Up the Plot Window ......................................................................................................................... 32Copying Data Into Orchestrator .................................................................................................................. 32

Index............................................................................................................................................................................... 33


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Notes, Cautions, and Warnings

This manual uses NOTES, CAUTIONS, and WARNINGS to emphasize important and critical instructions.

A NOTE highlights important information about equipment or procedures.

A CAUTION emphasizes a procedure that may damage equipment or cause loss of

data if not followed correctly.

A WARNING indicates a procedure that may be hazardous to the operator or to the

environment if not followed correctly.


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Chapter 1Introducing the Waveform &

Fast Data Samp ling Option

OverviewThe TA Instruments Waveform & Fast Data Sampling Option is a set of hardware and software tools used toquickly collect and analyze analog data signals generated by the TA Instruments ARES and RSA III rheom-eters. These tools can be used to:

Acquire dynamic mechanical data at a much higher rate than is possible with the standard rheometerfirmware (up to 100 points per second).

• Monitor and/or store the transient stress and strain signals graphically in real time to provideadditional information of materials during testing.

• Control external electronics using digital I/O lines, and synchronizing these devices to various events inrheometer tests.

The Waveform & Fast Data Sampling Option is integrated with the TA Orchestrator software, which can beused to control these packages through the standard Orchestrator test forms when the option is installed.

Components

The Waveform & Fast Data Sampling Option consists of aNational Instruments DAQ-Pad 6020E, BNC cables, andthe applicable software programs.

DAQ-Pad

The DAQ-Pad is a 12-bit 16 channel USB-based Analog toDigital converter, with 8 digital I/O lines and 100kS/ssampling rate.

Software Components

The following software tools are included with the Waveform & Fast Data Sampling Option:

• RheoCorr is a stand-alone data correlation and calculation application, that samples stress and strainsignals generated by the rheometer and calculates dynamic mechanical properties. RheoCorr uses high-speed data acquisition electronics and calculation algorithms to generate this data at rates much higherthan those available with the conventional rheometer electronics.

• RheoChart is a rheological strip-chart/oscilloscope that provides a graphical view of the rheometershear stress, normal stress, and/or strain signals. In addition to a graphical display of the results, thegenerated data can also be logged and copied directly into an Orchestrator spreadsheet for furtherdisplay, printing, or analysis.

National Instruments DAQ-Pad 6020E


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• DAQConfig is an application that is used to configure the external A/D hardware, and to indicatewhich rheometer signals are connected to which A/D channel. It can also be used to verify correctoperation of the National Instruments hardware and driver.

• NI-DAQ Files (National Instruments Driver Files) are used with the DAQ-Pad A/D converter, orsimilar hardware.

Although these applications are designed to be used side-by-side with the Orchestrator software, they can

also be used in a manual, stand-alone mode. See Chapters 3 and 4 for more details regarding the softwareapplications listed.

System Requirements

When setting up a computer system to operate your Waveform & Fast Data Sampling Option, follow therecommendations below to configure the system properly:

• Recommended Computer Configuration: Pentium III, 733 MHz or higher, 128 MB RAM, one free USBport required. Windows 2000/XP Operating systems.

• Required Software: Orchestrator version 6.6.1 or higher is required for operation of RheoCorr throughits remote interface. A valid Waveform & Fast Data Sampling Orchestrator key is required for operationof all products.

• Applicable Instruments: A TA Instruments ARES (firmware version 6.00 or higher) or RSA IIIrheometer (all versions).

• Data Acquisition System: Any National Instruments DAQ supported by NI-DAQ version 7 (0x700) orhigher. Analog Input: 4 differential A/D channels required, 12-16 bit, +/- 10 V, 100 kS/s minimumsampling rate. Digital I/O: Minimum of 3 Digital I/O lines required.


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Basic Steps for Operation

The process involved with the use of the Waveform & Fast Data Sampling Option involves several basic stepsoutlined below. See the indicated sections for further details on performing each step.

1. Install and configure the option as directed in Chapter 2 of this manual. The DAQConfig program

will be used to set up and test the device.

2. Set up your experiment on the rheometer. Install the appropriate tools and load the desired sample.Refer to the ARES Operator's Manual or the RSA III Operator's Manual for further information.

3. Set up your experiment within the Orchestrator software.

4. Begin the test and view the results using RheoCorr. You will be able to run the RheoCorr program

either from within Orchestrator or as a stand-alone program as detailed in Chapter 3.

5. Open RheoChart to view a graphical view of the rheometer shear stress, normal stress, and/or

strain signals. The generated data can also be logged and copied directly into Orchestrator for furtheranalysis. See Chapter 4 for further details.

NOTE: Only one instance of either RheoCorr or RheoChart may be open at one time.


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d. Changing the DeviceNumber: Select thecurrent device numberand click the Properties

button ( ).

The Configurationwindow is displayed. Set

the desired DeviceNumber and click OK.

e. Click the Test Panels

button ( ).

The figure shown to theright is displayed. Checkthe Last Error display.The display should readzero (0). If there is anumber other than zero,click the Error Codes

button to investigate thecause of the error.

6. Set the High and Low Input Limits to Channels 0, 1, and 2 to +5.0V and -5.0V, respectively.

7. Connect signal leads between the signal panel on the back of the rheometer and the DAQ-Pad input jacksvia shielded cables with BNC connectors. Follow the table below to connect the cables. For more detailssee the TA Instruments instruction sheet, "Unpacking/Installing the Waveform & Fast Data SamplingOption," PN 402021.000.

ARES Port to DAQ-Pad Channel RSA III Port to DAQ-Pad Channel

Torque Out ACH 0 Not usedStrain Out ACH 1 Strain Out ACH 1Normal Out ACH 2 Torque Out ACH 2

8. Install the BNC shorting plugs on the unused analog input BNC channels on the DAQ-Pad.

9. Follow the instructions in the next section to configure the DAQ-Pad.

Test Panel Window


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Using the DAQConfig Utility

The DAQConfig program is used to configurethe hardware device, the DAQ-Pad, with thesoftware. Follow the steps below:

1. Click the icon on the desktop to open

the TA Instruments DAQConfig applica-tion. The opening window (see the figureto the right) allows you to set up the device.

2. Enter the correct Device Number obtainedfrom the Test Panel window seen in thefigure on the previous page.

3. Press the Test button to the right of theDevice Number field on the DAQ Con-figuration Utility window. A green

"Device Passed" message should appearnext to the Test button indicating success-ful configuration. If a red "Device Failed"message appears, check to verify that thecorrect Device Number has been entered,then go back the National Instruments TestPanel window for help in troubleshootingthe problem.

4. Choose the Rheometer Setup by selectingeither ARES Class (Shear) or RSA III Class(Linear) on the DAQ Configuration Utilitywindow as appropriate.

5. Under the Channel setup fields, enter theA/D channel number corresponding to thesignal input from the rheometer. Enter theFull Scale voltage setting for each signal.Note that torque, normal force, and measured strain signals are all scaled to +/- 5.0 full scale.

CAUTION: To avoid possible damage, do not set the Full Scale voltage below 5.0 V.

6. Under the UV Source fields, check the “UV Source Available” field if this option is to be used in conjunc-tion with an external UV source. Select the appropriate UV Source below being used (either the ExoNovacure 2100 or TA Instruments PCA).

CAUTION: Verify that the selection made matches the actual hardware used. Failure

to do this could result in incorrect triggering of shutter in the UV source

(continued)

DAQ Configuration Utility Window


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7. Verify that the selections made for I/O Signals match the actual pins used in the DAQPad. Please seeUV Curing documentation for additional information.

8. Press OK to save changes.

The device should now be configured with the software and ready for use. See Chapter 3 for details on usingthe RheoCorr portion of the Waveform & Fast Data Sampling Option.


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Chapter 3RheoCo rr External Correlator

OverviewThe RheoCorr External Correlator is a Windows® application that is used with an ARES or RSA III rheom-eter and an external analog-to-digital acquisition system, the National Instruments DAQ-Pad, to calculate thedynamic mechanical properties of a material. RheoCorr works in conjunction with the TA InstrumentsOrchestrator software receiving measurement parameters, instrument calibration parameters, and test statusinformation from Orchestrator. The program then sends the test data back to Orchestrator as the measure-ments are completed. It may also be used in a stand-alone mode to independently monitor the torque andstrain waveforms while measurements are made in the rheometer

The RheoCorr program samples the analog voltages generated by the rheometer and uses a cross correlationalgorithm to calculate the magnitude of each signal, and the phase shift between them. With this informa-

tion, and stress and strain geometry constants provided by Orchestrator, it is possible to determine therheological properties of the sample currently being tested. This information can be sent to Orchestrator as itis generated, and the results displayed as a conventional test.

RheoCorr uses the same algorithms forthe collection of data as those used inthe ARES and RSA III rheometers. But,

because of the faster sampling ratesavailable in the external DAQ electron-ics, and the calculation algorithmsimplemented in the software, dynamicmechanical data can be calculated atmuch higher rates than those offered by

the standard rheometer hardware.

Introducing

RheoCorr

After installing the software (seeChapter 2 for information), select Start/ Programs/TA Orchestrator Tools/ RheoCorr External Correlator to openthe program. The window shown in

the figure to the right is displayed.

When in Run mode, the plot windowscontain a representation of the analogsignals generated by the instrumenttransducer and motor, along with displayed information and controls that allow you to perform variousfunctions.

The next section provides an explanation of the RheoCorr fields displayed on the opening window.


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Understanding the RheoCorr Fields & Buttons

The fields and buttons that are found on the RheoCorr opening window have various functions as described below.

RheoCorr Fields

NOTE: Fields with multiple units use the units last used with Orchestrator. For example, if

Orchestrator is set to use SI units, modulus in RheoCorr will be displayed in [Pa].

Field Units Description

Plot Layout Used to toggle the plot between two different plot formats:

— Time Based plot where the stress and strain signals areplotted as a function of the total points used in the correlation.

— Lissajous plot where torque is plotted versus strain.

Correlation Parameters

Frequency [rad/s] [Hz] This field sets the frequency used for the correlation calculation.In local mode this can be used to set the desired frequency. Inremote mode it will be automatically set to the test frequencyprogrammed in Orchestrator.

Cycles Select the number of sinusoidal cycles used for the correlationusing this field.

Pts/Cycle Use this field to set the number of samples acquired in each cycle.

Meas Time [s] This field is used to set the period of time between each dynamicpoint measurement.

Current Status

Time [s] The elapsed time since the start of the test.

G* / E* [dyn/cm2][Pa] The last value calculated for complex modulus (G* in shear, orE* in linear geometries)

Phase [º] The last value calculated for the phase shift between the stressand strain signals.

Points The number of correlated data points measured since the startof the test.

Torque/ [gm-cm] The last value calculated for the correlated torque (ARES)Force [gm] or force (RSA-III)

Theta/ [mrad] The last value calculated for the correlated motor angular Displacement [microns] displacement (ARES) or linear displacement (RSA-III)


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RheoCorr Buttons

Button Status Indication Action

Optional external trigger on Indicator only - no action when pressed

Optional external trigger off

Amplitude of correlatedstrain Indicator only - no action when pressed

indicates that signal is present

No signal present

Data acquisition/ Indicator only - no action when pressed

correlation running

Not running

Running in stand-alone mode Indicator only - no action when pressed

Controlled by Orchestrator

Run - Start the test Toggles between Run and Stop. Pressing this

button starts or stops data acquisition

Stop - Stop the test when in local mode.

--- Queries Orchestrator for current test frequency,transducer, and geometry scaling constants.

--- Pressing this button launches the External

Trigger Control window (see page 20).

--- Pressing this button launches DAQConfig

Setup window. This can be used to setup thehardware configuration and scaling.

--- Opens the online help system.

--- Terminates RheoCorr and closes the window

when in local mode or hides the applicationin remote mode.


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Learning About the RheoCorr Plot Window

The RheoCorr plot window (see the figure to theright) shows the last full waveform buffer, plottedas both torque and angular displacement versussample number (Time-based plot). The plot can also

be displayed as a Lissajous plot showing torque as a

function of displacement.

The plot is automatically scaled to show the entirerange of data. (There are no provisions for manu-ally changing the axis scaling.)

The Plot Layout radio buttons, located beneath theplot, are used for toggling between the Time-basedand Lissajous plots.

Right click onthe plot to bring

up a pop-upmenu (shown inthe figure to theright) withfunctions for changing the plot setup and copying thedata buffer into Orchestrator. See the next two sectionsfor information.

Setting Up the Plot WindowClick Set Graph Options on the RheoCorr right-click menu to display the Graph Setup window shown inthe figure below. The Graph Setup window can be used to change the colors used for data curves, plot

background, and grid lines used for the plot. Colors are changed by pressing the appropriate color button,which then displays a color selection dialog, allowing you to select the desired color.

RheoCorr stores thesesettings, and once they have

been changed, these changesremain in place until changedagain.

Lissajous Plot

Time-Based Plot


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Copying Correlation Buffer Into Orchestrator

When you select Copy Correlation Buffer into Orchestrator from the right-click pop-up menu, the data thatis currently displayed on the RheoCorr plot is immediately sent to Orchestrator. This function takes datafrom the current plot, and copies it into Orchestrator, creating a new page that contains the waveform bufferdata.

• The data is sent as time, torque, and angular displacement when used with an ARES rheometer.

• The data is sent as time, force, and displacement when used with an RSA III rheometer.

If Orchestrator is not currently running, then this function is disabled.

Downloading Data Into Orchestrator

This function can be used in local mode to dump a copy of the correlated data into Orchestrator. Whenselected a new page is created in Orchestrator that contains all of the data measured since the start of the run.The data is sent as time, modulus (G* or E*), and phase angle. Note that when the data is transferred usingthis method it is not possible to use the Plot Layout or Load Spreadsheet Variables function to calculateadditional rheological parameters, however it is possible to use the Orchestrator equation editor to calculatethe desired parameters.

This function is disabled if Orchestrator is not running, or if RheoCorr is running in remote mode.


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Running RheoCorr in Local Mode

The RheoCorr correlator can be used as a standalone application to monitor the torque and strain signalsgenerated by the rheometer, and to calculate complex modulus and phase angle over time. This can be usedto look for things such as harmonic distortion and noise in the signals, which can give insight into the accu-racy of the data being generated by the rheometer.

To use RheoCorr in local (or stand-alone) mode, follow these steps:

1. Set up and run your test in Orchestrator as usual.

2. Select Start/Programs/TA Orchestrator Tools/RheoCorr External Correlator. The application starts inlocal mode, which indicates that the Correlation Parameters (Frequency, Cycles, Pts/Cycle, and MeasTime) are now active.

NOTE: The Frequency, Cycles, and Pts/Cycle fields can only be changed when RheoCorr is

in Idle mode (i.e., not performing acquisitions).

3. Click the Scaling button to manually update the scaling factors to the most current test settings used inOrchestrator. When used in local mode, RheoCorr uses the last set of scaling factors obtained fromOrchestrator for scaling torque and strain. These factors include current test frequency, transducerscaling, and stress and strain constants based on the last geometry used by Orchestrator when a test isstarted with the external correlation option enabled.

4. Click the Run button to start collecting data. Data acquisition and analysis will continue until the Stop button is pressed.

Setting Up Correlation Parameters

When using RheoCorr in local mode, the following Correlation Parameters settings are recommended:

• Frequency: The frequency used byOrchestrator is automaticallytransferred when using the Scaling

button. If a different frequency isdesired, such as testing for harmonics, the new frequency can be set just prior to activating the Run

button. This field can be in either [rad/s] or [Hz], based on the units settings in Orchestrator. Make surethat the value entered is appropriate for the frequency units displayed.

• Cycles: Choose the desired number of waveform cycles over which the correlation will be performed.Increasing the number of cycles results in additional signal averaging, which in principal can give moreaccurate and consistent data at the expense of a slower response to changing signals.

• Pts/Cycle: Select the number of data points used in each waveform period (cycle). More Pts/Cycleshould result in more accurate data. Keep in mind that the sampling time used by the A/D hardwaredepends both on the Pts/Cycle, and the Frequency. In general, low frequencies should use large Pts/Cycle values, and high frequencies should use smaller values. Care should be taken to ensure that thecombination of frequency and Pts/Cycle does not result in a sampling rate that is too high for theelectronics. If the sampling rate is too high for the A/D converter an error message is displayed in themessage line, and the test is stopped.


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• Meas Time: Select the rate at which the acquired data are to be correlated to generate a dynamicmechanical data point.

NOTE: The Meas Time value can be set independently of the frequency and cycles. See

"How Data is Correlated" for more information.


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Running RheoCorr with Orchestrator

The RheoCorr correlation system can be used in conjunction with Orchestrator (version 6.6.1 or higher) tosynchronize data acquisition and testing parameters with tests run in the rheometer, and to automaticallytransfer the data generated into Orchestrator as a second "online page." Once the data has been transferred toOrchestrator it can be manipulated as standard Orchestrator data.

Follow these instructions to use RheoCorrwithin the Orchestrator program:

1. Open Orchestrator. Select the Start button, the Edit/Start Instrument Testwindow is displayed as seen in thefigure to the right.

2. Scroll through the Test Setup list andselect the Dynamic Temperature RampTest or the Dynamic Time Sweep Testfrom the list.

3. Click the Edit Test button. The param-eters window for the chosen test will bedisplayed. See the figure below for anexample.

4. Click the Options button.

When Orchestrator detects the presenceof the external correlation software itadds a new option to the temperature

ramp and time sweep tests labeledExternal Correlator, which allows you

to enable the external correlation hardware andsoftware.

5. Check the External Correlations box to displaythe options available. See the figure to the right.The options are described on the next page.


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External Correlation Options

Field Field Type Description

External Correlation Check Box Enables or disabled the external correlation option.

Measurement Time [s] Floating point Used to set the rate at which sample data is collected.

(1 pt/sec maximum.)

Correlation Cycles Integer Used to set the width of the correlation buffer used tocalculate the data.

Enable External Check Box When checked it enables the external trigger option.Trigger (Not used, future option).

NOTE: In remote mode, the number of points per cycle used in the calculation is set based

on the measurement frequency, and cannot be changed by the operator. The table below

shows the number of points used for calculation over the various frequency ranges.

Frequency [rad/s] Points/Cycle

ω < 2.0 655362.0 < ω


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When used in this fashion, Orchestrator launches RheoCorr in remote mode, then sends information on thecurrent test parameters, transducer settings, and calibration factors to the RheoCorr application. RheoCorrwaits for a signal from Orchestrator that the test has begun, at which point data collection starts, continuinguntil an end of test signal is received from Orchestrator. When the test is completed RheoCorr automaticallyterminates.

When operating in remote mode, none of the values in the RheoCorr Correlation Parameter fields can bechanged and the application can only be terminated by stopping the test running in Orchestrator.

NOTE: The status of the RheoCorr correlation can be viewed from within Orchestrator by

selecting the "RheoCorr" real-time indicator. When present, this indicator turns green when

RheoCorr is running and displays the current number of data points sent by the correlator to

Orchestrator. See the table below.

Display Description

(blank) RheoCorr option is not enabled.

RheoCorr Option is enabled and not running.

Blocked Option cannot be used because another instance is already running.

Error RheoCorr option is in an error state.

## pts RheoCorr option is acquiring data. Shows current point count.

If a test is started in the blocked state, the errormessage shown in the figure to the right appears.

Once the data is in Orchestrator it can be manipu-

lated as standard dynamic mechanical rheologicaldata, and all of the standard dynamic variables can be calculated and loaded into either the spreadsheetor plot. Data is saved as standard Orchestratordata files.


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Additional Information on RheoCorr

The following general information is presented in addition to that alread provided in this chapter.

• RheoCorr responds to changes in transducer settings during Autoranging in the rheometer, howeverdue to timing issues, there may be "glitches" in the data during transitions from one transducer settingto the next.

• It is generally advisable to operate the A/D electronics with both the torque and strain channels set to a+/- 5 V sensitivity (the full scale value for the motor and transducer). If the signals generated are goingto be much lower than that, additional sensitivity can be obtained by setting either or both of theseparameters to lower values, taking care that an input overload does not result.

• RheoCorr automatically filters out data if the correlated strain value is below 0.1% of the full scaletransducer reading. This is used to filter out any data points that may be based on data collected duringtime periods when the instrument motor was not applying strain to the sample (this is indicated by the"Data On/Data Off" indicator). This, however, does not remove data that may be collected over periodsof partial motor movement, which can result in "glitches" in the reported data.

• When running in remote mode, RheoCorr continuously measures data when the rheometer is running a

test, assuming that the instrument motor is continuously applying strain to the sample. Instrumentoperators such as Autotension can result in periods of time when there is no dynamic motor motion,which may generate glitches in the data if the data filtering function does not catch all periods of timewhere the motor is not moving.

• The data collection process is very time sensitive, and requires that CPU and memory resources of thehost computer be available when the data need to be offloaded from the external DAQ electronics. If thehost computer is busy running other resource intensive applications, it is possible that the programmedacquisition may fail, resulting in an acquisition error and terminating the run with an "DAQ Error:Reading data of a continuous acquisition." Care should be taken to ensure that the host computer is notrunning any unnecessary application while running these tests, particularly when collecting data athigh data rates.

How Data is Correlated

There are two steps involved in the data correlation process:

1. Acquisition of the raw stress and strain values.

2. Calculation of the phase and amplitude values from the acquired data via cross correlation.

In order to provide maximum flexibility the RheoCorr correlation software is designed to handle these twoprocesses independently.

Data samples are placed into an acquisition buffer at a rate determined by the combination of test frequency,number of points per cycle to be acquired, and the number of cycles over which to perform the correlation.From this information the data sampling rate can be calculated, as well as the total number of samples thatmust be stored for the correlation. When the acquisition is running, data is collected asynchronously at thisrate by the A/D hardware. New data is added to the correlation buffer in a bucket-brigade fashion—that is,the oldest data is removed as the newest data is added in such a way that the correlation buffer is alwayscompletely filled with the most recent data.


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Under-Sampled Measurement

Over-Sampled Measurement

Effect on Measurement Time

Data correlations are made using the correlation bufferat a rate given by the Meas Time field. At this timeinterval the acquisition hardware transfers any recentlysampled data, and the calculations proceed.

Because the measurement time is set independently of the period of time necessary to fill the correlation buffer,it is possible to both "over sample" and "under sample"the measurement. See the two figures in this section forreference.

• In the case of an over-sampled measurement (shown inthe figure above right), the measurement time islonger than the period required to completely refillthe correlation buffer, so not all of the data acquiredis used for the data calculation.

• In the case of an under-sampled measurement (shownin the figure below right), the measurement time isshorter than the time required to refill the correlation

buffer, so individual points in the acquired data may be used for more than one point calculation.

In general, the fewer number of cycles that are used forthe correlation, the faster the data can change in responseto changes in the sample. Increasing the number of cyclesused for the correlation (and hence the time over whichthe data are integrated) can result in smoother dataresults at the expense of the sharpness of features.


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Chapter 4 RheoChart Str ip-Chart Appl icat ion

OverviewThe RheoChart application is used toprovide a rheological oscilloscope or strip-chart view into the stress and strain signals

being generated by a Rheometric Seriesrheometer. RheoChart samples the analogvoltage signals generated by the rheometerand using instrument calibration factorsand geometry information provided byOrchestrator converts these signals intomeaningful stress and strain values. There

are also provisions available for loggingand exporting this information into Orches-trator for further analysis.

RheoChart is capable of displaying up totwo signals simultaneously, typically stressand strain.

Introducing

RheoChart

After installing the software (see Chapter 2for information), the RheoChart application can be opened

by selecting Start/Programs/TA Orchestrator Tools/ RheoChart Strip Chart or by selecting View RheoChart fromthe Orchestrator View menu. The window shown in thefigure above is displayed (with Autoscaling turned on). (If Autoscaling is turned off, the window shown in the lowerfigure is displayed.)

The window contains a plotted representation of the incom-ing data along with displayed information and controls thatallow you to perform various functions.

The next section provides an explanation of the RheoChartfields displayed on the opening window.

RheoChart with Autoscale Off

RheoChart with Autoscale On


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Understanding the RheoChart Fields & Buttons

The fields and buttons that are found on the RheoChart opening window have various functions as described below.

RheoChart Fields

Field Units Description

Display Period Seconds Sets the time period over which data is displayed.

Scale (Depends on setting) Sets the full scale plotting value for the signals.

Offset Percent The plot offset applied to the plot scale.

Average The average value for a given signal over the chart period.

Signal Drop list used to choose signals for the right axis of

the strip chart.

The signals available include:RSA: Displacement (mm) or NoneARES: Displacement (rad), Normal (gm), or None

Point Count Displays the number of points contained in the datashown.

RheoChart Buttons


Data acquisition/ Indicator only - no action when pressed

correlation running

Not running

Logged on to Orchestrator Indicator only - no action when pressed

Logged out of Orchestrator

Plot is autoscaled Press to toggle autoscaling on or off.

Plot is not autoscaled

(table continued)


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--- Starts logging data.

--- Copies data log and sends the results to

Orchestrator spreadsheet.

--- Clears the point counts and starts logging

new data.

Run - Starts the test Toggles between Run and Stop. Pressing this

button starts or stops data acquisition.

Stop - Stops the test

--- Queries Orchestrator for current transducer

and geometry scaling constants.

--- Pressing this button launches DaqConfig

Setup window. This can be used to setup thehardware configuration and scaling.

--- Opens the online help system.

--- Terminates RheoChart and closes the window.


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Learning About the RheoChart Plot Window

The RheoChart plot window (see thefigure to the right) shows the last fullwaveform buffer, plotted as bothtorque and angular displacementversus sample number (Time-based

plot).

The plot is automatically scaled toshow the entire range of data. (Thereare no provisions for manuallychanging the axis scaling.)

Right click on the plot to bring up apop-up menu (shown in the figure

below) with functions for changing theplot setup and copying the data bufferinto Orchestrator. See the next twosections for information.

Setting Up the Plot Window

Click Set Graph Options on the RheoChart right-click menu to displaythe Graph Setup window shown in the figure below. The Graph Setup

window can be used to change the colors used for data curves, plot background, and grid lines used for theplot. Colors are changed by pressing the appropriate color button, which then displays a color selectiondialog, allowing you to select the desired color.

RheoChart stores thesesettings, and once they have

been changed, these changes

remain in place until changedagain.

Copying Data Into Orchestrator

When you select Copy Data into Orchestrator from the right-click pop-up menu, the data that is currentlydisplayed on the RheoChart plot is immediately sent to Orchestrator. This function takes data from thecurrent plot, and copies it into Orchestrator, creating a new page that contains data for time and the current

signals for channel 1 and channel 2.

The data is sent as time, torque, and angular displacement when used with an ARES rheometer.

• The data is sent as time, force, and displacement when used with an RSA III rheometer.

If Orchestrator is not currently running, no action takes place when this function is selected.


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Index A

A/D electronics 26

acquisition buffer 26

analog voltage signals 29

angular displacement 18

ARES 7, 15, 19, 32connecting to DAQ-Pad 12

C

cablesconnecting 12

Channels

setting 12, 13

colorsetting 18, 32

colorssetting 18, 32

complex modulus 21

components 7software 7

configuringdrivers 8

hardware 8signals 8

copyingcorrelation buffer into Orchestrator 19

correlation buffer 26copying into Orchestrator 19

correlation cycles 24

correlation parameters 21

correlation process 26

correlator. See RheoCorr

cross correlation algorithm 15

D

DAQ Quick Start Guide 11


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DAQ-Pad 7, 11, 15configuring 13installation 11

connecting cables to instrument 12testing 12verifying functionality 11

DAQConfig 8, 13, 20

data acquisitionstarting 17, 21stopping 17

data analysisstarting 21

data aquisition rate 7

data correlation 7

Device Number 13accepting 11changing 11

dynamic mechanical properties 7

E

error codes 12

External Correlationoptions 24

External Correlations box 23

external correlator. See RheoCorr

external electronics 7

G

geometry 21

graph setup 18, 32

grid linessetting 18, 32

H

hardwareverifying functionality 11

harmonic distortion 21

High and Low Input Limits 12


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I

installation 11 to 14DAQ-Pad 11license key 11Orchestrator 11

introduction 7

L

license keyinstallation 11

Lissajous plot 16

M

Measurement and Automation program 11

measurement time 27

memory resources 26

N

National Instruments driver files 8

NI-DAQ 8

noise 21

number of cycleseffect on correlation 27

O

Orchestrator 11, 15, 16, 18, 21, 25, 29, 32copying correlation buffer into 19copying data into 32key 8running RheoCorr 23version 8

Orchestrator key 8

over-sampled measurement 27

P

parametersinstrument 15

phase angle 21


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plotcopying into Orchestrator 19, 32setting background color 18, 32setting curve color 18, 32setting grid lines 18, 32setting up 18, 32

plot background

setting 18, 32plots

Lissajous 18

program functions 7

R

RheoChart 7 buttons 30

Acquire 30Autoscale 30Idle 30Log On/Off 30

fieldsAverage 30Display Period 30Offset 30Point Count 30Scale 30Signal 30

introduction 29plot window 32setting up plot 32

RheoCorr 7, 15

additional information 26 buttons 17

Acquire 17DAQ Setup 17Data On/Off 17Exit 17Help 17Idle 17Local/Remote 17Run/Stop 17Scaling 17Trigger 17

correlation parameters 21external trigger control 20fields 16

Cycles 21Frequency 21G* / E* 16Meas Time 21


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Phase 16Plot Layout 16Points 16Pts/Cycle 21Time 16Trigger 16

filtering data 26opening window 15

plot window 18running in local mode 21running in remote mode 25running with Orchestrator 23setting up plot 18

rheological properties 15

Rheometer setup 13

RSA III 7, 15, 19, 32connecting to DAQ-Pad 12

S

sample interval 24

sampling rate 21. See also data aquisition rate

scaling constants 17

scaling factors 21

signalsanalog voltage 29calculating magnitude 15noise 21phase shift between 15

scaling 13

strain constants 21

strain signals 7, 21

strain waveformmonitoring 15

stress constants 21

stress signals 7

strip chart program 7

stripchart application.See also

RheoChartsystem requirements 8


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T

testsDynamic Temperature Ramp 23Dynamic Time Sweep 23used with correlator 23

time-based plot 16

torque 18

torque signals 21

torque waveformmonitoring 15

transducer scaling 21

Triggercycling 20number of cycles 20time off 20

Trigger events 20

U

under-sampled measurement 27

V

viewgraphical 7

W

waveform cycles 21

Documents

Waveform & FDS