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Simple measurement using Dewesoft DAQ hardware

Simple measurement with different sensors and Dewesoft hardware. Basic presentation for new users, that will show you how to connect different sensors to Dewesoft hardware and how to perform the measurement.

First we need to install Dewesoft X on the computer. You have to download Dewesoft X software from our page. Download and run the Installer. Dewesoft X supports the operating system Windows, Version 7 (32-bit and 64-bit) and newer.

Licensing

  • The license for measuring with Dewesoft X is included in the device (usually PROF version). Once it is connected on the USB port, it acts as a dongle.
  • The license for analysing is free! Dewesoft X can be installed on any computer and the stored data files can be opened, recalculated, and exported.
  • Additional licenses can be required for plugins, these can then also be written into the Dewesoft® device. To test plugins, you can request a 30-days-Evaluation license.

More information about licensing can be found here. On the following link, you can also find the information about plug-in installation and registration.

In this simple measurement lesson, we will show simple measurement of various sensors using Dewesoft SIRIUS system. One sensor after the other will be connected and a basic measurement will be done. It makes sense to work this through from the start to the end, as with each measurement more details and different instruments and functions are shown. In the picture below, you can see the demo equipment that was used.

The demo kit consists of the SIRIUS device, with its installation USB stick and the three sensors:

  • Acceleration sensor
  • Tuning fork
  • Encoder

Dewesoft X launcher

When we connect the power and USB connector to the computer, Dewesoft X will pop out from the auto detect screen and show the devices with their serial number, the status of power supply and status of synchronization cables in case we have more than one unit connected. Pressing Run Dewesoft will close the popup and start Dewesoft X software.

Manual setup of hardware

In case you need to manually setup the hardware, please start Dewesoft X and go to Settings → Settings.

Under Devices, set the operation mode to “Real measurement”. Then scan for the hardware with the double-arrow button.

The SIRIUS will be found with the according serial number.

For more informations about Settings, visit the How to set up Dewesoft course.

When you leave the Settings menu with OK then, you should get the “Channel Setup” screen, showing the instrument with the built-in amplifiers.

Notice, the two buttons on the left upper corner – Acquisition and Analysis. One mode is for storing the data, the other is fo reloading data files and analysing them.

You should be now in Acquisition mode, on the Channel setup tab.

We connect an IEPE accelerometer on the first channel.

  1. First, think about the required sampling rate. What is the highest input frequency we expect? In the drop down “Dynamic acquisition rate” the default value is usually 20 kS/s, which is fine for now.
  2. If not already set, activate the channel by setting it to “Used”.
  3. As the SIRIUS-ACC amplifier supports two input modes, in the row of the first amplifier please set the “Measurement” from Voltage to “IEPE”, so the amplifier will supply the sensor. If the “Ampl. name” (and the LED ring on the instrument around the BNC connector) gets green after a few seconds, we know that the sensor impedance is OK.
  4. Then enter the Channel setup window by pressing the “Setup” button.

Channel setup

The Channel setup window splits up into left (Amplifier settings) and right (Sensor settings) side. Furthermore, you can change the name

  • Amplifier settings - With the “Dual core” option set (if you own a Dual-core SIRIUS), we don't have to care about the input range. On the bottom you see a quick preview of the sensor signal, knock on the accelerometer for testing.
  • Sensor settings - In our case the accelerometer has built-in TEDS (transducer electronic data sheet), so automatically all the calibration factor and calibration data (by the way: out of date, see red warning) is read from it. In any other case - Enter the “Physical quantity” (Acceleration) and the “Unit” (either g or m/s²) and the calibration factor below, or put the sensor on a reference shaker and press the “Calibrate” button.


Storing

  1. Before starting the measurement, please go to the Storing ribbon, and specify a file name. The Storing type is set to “always fast”, here you can specify trigger conditions later.
  2. Then click the red Store button.


Recorder

Dewesoft X switches to Measure mode.

For faster navigation on top there are 3 screens (Recorder, Scope and Custom...) predefined. The screens contain instruments, and can be freely defined.

The “Recorder” screen currently consists of one Recorder instrument. Do a few hits on the accelerometer.

The recorder y-axis automatically adapts to the currently visible minimum/maximum values. In the Recorder properties on the left “Auto scale” is enabled.

On the right side is the channel list, showing the channel currently assigned to the Recorder instrument.

After you have done the measurement, please click STOP (1), then change to ANALYSIS (2) mode.

Analysis

Let's take a look at the recorded data. You are now in "Analysis mode". The last recorded data file is automatically reloaded. Let's zoom into one of the peaks.

Move the cursor into the recorder. Press the left mouse button, hold it down while moving to the right, then release. If you move the mouse between the two cursors, there is a small + attached to the cursor, now click.

To zoom out to the previous level again, simply click the right mouse button.

You can zoom in until you see the sampling points (20 kHz).


Export

Only the selected region (in the overview instrument on top) will be exported!

Go to the Export section (1), select “File Export” (2), chose the file type and properties, enable or disable channels from the right, then click the Export (3) button.


The FlexPro and MSExcel “Active X” ribbons on top will export into a template, which you can adapt, in order to directly export in your finished report.

To learn more about acceleration sensors and vibration measurement, visit Vibration measurement course.

We connect a strain gage on one of the STG inputs of our SIRIUS.

A "tuning fork" is normally used for tuning the instruments of an orchestra. It is tuned to 440Hz, which is the standard pitch (note 'a'). In our demo tool a quarter bridge strain gauge with either 120 or 350 ohms resistance (is marked on the connector) is mounted on the steel, therefore we can measure the strain of the vibrations.


In the left upper section we find the amplifier settings. Set to "Bridge" and "Quarter bridge 3-wire", either 120 or 350 ohm (written on connector).

You directly see the according circuitry, how to connect the quarter bridge on the 9pin DSUB connector.

Select an appropriate range, if you use the highest, you don't have to care about overload (input voltage exceeding amplifier range).

We use a smaller range, e.g. 20mV/V. The higher ADC is now working in the 20mV/V input range, while the lower

ADC input range is 5% of it, 1 mV/V simultaneously.

So you get an amazing dynamic!

On the right side (Sensor settings), we select Physical quantity “Strain” or “Stress” and the unit. As the TEDS tab is shown, we see that this sensor is already equipped with TEDS chip, and all the settings are read from it automatically.

Balance sensor

Before starting the measurement, we need to balance the strain gage. Click “Balance”, the output will go to 0 um/m, and the offset will be shown next to the button.

Sampling rate

Because the natural frequency of the tuning fork is 440Hz, we have to think at which sample rate we want to digitize the signal. In theory, a factor of 2 (=880Hz, Nyquist criteria) would be sufficient, in praxis however it depends very much how the signal looks like. We suggest a factor of 10 or even 20 to get a good result.

So, the sample rate is still fine with 20 kHz.

Go again to "Storing", specify a filename, e.g. "tuning_fork_measurement". Then click "Store".

Scope

Now we switch to the second prepared screen called “Scope”. It is again a screen with only one instrument, the scope, maximized over the whole area.

  1. Switch to the Scope screen
  2. Hit the tuning fork, that we have an oscillating signal, then click the y-axis label for min/max scaling.
  3. Set the trigger to Auto, in the properties of the left.
  4. Move the trigger level up- or downwards with the mouse, until you get a triggered image.
  5. With the +/- buttons on the x-axis, you can adjust the time window shown.

Customizing screens

Now we want to add an FFT instrument, to measure the resonance frequency of the tuning fork.

The third screen is called “Custom...”, but basically every screen can be adapted to your needs.

Design mode

Go to the “Design mode”, either by clicking the hammer/ruler symbol on the left or the “Design” tab on the top.

The instrument toolbar will show up and display all available instruments. We pick the FFT.

Automatically the channel “AI 5” is assigned to the instrument. As you are in “Design mode” you can now freely adapt the size of the FFT and move it to your favourite location on the screen.

FFT instrument

Following steps help to get your data displayed quickly with the FFT:

To be able to change the instrument, you need to exit Design mode first! Click again the Design mode tab.

  1. Set “y-axis” to “Log”
  2. Click on the y-axis lower limit, and change it to e.g. 0,001 um/m.
  3. Hit the tuning fork, let it vibrate, then click on the peak. A cursor will appear, showing the maximum of 439,5 Hz with the according amplitude.

Analysis folder view

After stopping the measurement, when you click two times on the Analysis button, you get to the Analysis folder view, it is like an Explorer. On the bottom, you get information about the channels and data header, and with the powerful search fields you easily find the data file you are looking for.

To learn more about strain gages and how to measure strain and stress, visit our Strain measurement course.

Now we connect the demo encoder to e.g. ACC+ or STG+ (with additional Lemo connector), or MULTI module.

Per default the Counter inputs are not visible in Dewesoft X, we have to add them with the green “+” button from the Module Manager.

Also, other software options can be added here, e.g. Power, Order tracking, Modal test...

The Counters will appear now as a ribbon on top.

The buttons on top can be customized, click the “+” button again, go to “New setup defaults” and set the asterisk for the Counters. From now on they will appear as default each time when starting Dewesoft X.


There are two typical counter techniques: the gated measurement (high-frequency range typical > 100 Hz) or pulse width measurement (low-frequency range typical < 100 Hz). Many applications need both: the counter information and the analog data. Traditional systems do not offer the counter information synchronised to the A/D converters because they get the counter information only either after the gate time or after the pulse time measured. In comparison to standard counting with software interpolation (value 1.5 in the example image) Dewesoft X real-time counting uses an additional counter on a 102 MHz time base to get the exact time of the rising edge of the signal. This unique feature allows the calculation of the exact counter value at the A/D sample point (value 1.87 in the example).


When you turn the encoder, you should already see the Counter value increasing.

Each counter (CNT x) consists of 3 digital inputs (IN0, IN1 and IN2). Set the channels to Used and enter the Setup.


Counter setup

In our case, we have a 1024-pulses Encoder with A, B and Z track. Set the basic application to “Sensor (encoder...” and the sensor type to “Encoder-1024”. Enable the “Encoder zero”, so the angle will be reset with the Z pulse once per revolution.

The most important output channels below are Angle, Frequency, and Raw_Count.

Go to design mode and add Analog meter, Digital meter, and Recorders. Set the properties on the left for each instrument (min, max values, and resolution).To assign/unassign a channel to an instrument, click on the instrument first, then select/deselect the channel from the channel list on the right.


Analog and digital meter

Below you see some example properties for the analog and digital meter.

This should help you for displaying your RPM signal.


Save setup

After you have done all the sensor settings and created your own screen, you can save this setup/display configuration to a setup file (*.dxs).

Therefore stop the measurement, or go back to Channel setup, then click the Dewesoft X icon button, and use “Save setup as...”.


The same way you can load any configurations.

To learn more about counters and angle sensors, visit our Digital counters course

In Dewesoft X, we have extended math library and several software modules for special applications. Let's only look to one of them as an example, you will find more. We will use Power module to calculate active power and we will measure grid frequency. First we must add Power module - press '+' button and select Power grid analysis.

We have several settings and calculation options, but for basic measurement, we only need to assign the right channels. For U1, we select »voltage« channel and for I1 we select »current« channel.

When going back to measure screen, we have several predefined displays related to the power module and we can, of course, create our own as a combination of power and other parameters.

After setting the input and math channels, we are prepared to perform a measurement. Let's store some data by pressing the Store button. Once the data is stored, we can press Stop to stop the recording.

By pressing Analysis, the file can be review for analysis. We can look on different screens and by pressing Play, we can replay the data.

For the analysis of data, Dewesoft X offers several possibilities. We can do Offline math inside the software, we can export data to other software packages or we can simply print the display which we would like to add to report. Of course, all file operations like merging the files together, renaming and deleting them are possible.

By selecting the print button, the selected display will be printed out:

We can also export data in various formats (Excel, Matlab, Diadem, Flexpro, ...) by selecting Export function:

If we want to perform additional analysis on data already stored, it is very easy to do Offline math inside Dewesoft X. Here we will calculate vibration velocity out of an acceleration signal. To do that we must select Offline math button:

Choose '+' button Add math and select Integral, derivative for our case.

In the setup, we select acceleration channel, on which we will perform integration. Please note that the system will already suggest the units of measurement to be mm/s and do automatic conversion. We can, of course, select alternative unit, like ips.

After we have done this, we go back to Review, add one Recorder display on which we will put acceleration signal and our math signal – vibration velocity. To calculate this math signal, we must click on Recalculate button. Now we can see both signals.

There are many things to do in Dewesoft X and we invite you to visit further sessions on different topics How to measure signals, How to analyse the data and How to use Dewesoft X.

Sine wave on all channels

In case you have set the Operation mode in Dewesoft X to “Simulation” mode, you will get a picture like below: sine waves with random amplitude and frequency on all channels.

When you switch back to Ch. Setup, the amplifiers will show “Demo-...”. In this case, please review the upper page - Manual setup of hardware.

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