Download Use of various DAQ equipment - Faculty of Mechanical Engineering

Chapter 1
Use of various DAQ equipment
The laboratory exercise Use of various DAQ equipment is placed on the Faculty of Mechanical
Engineering in the Laboratory for Water and Turbine Machinery.
1.1
Introduction
With this exercise students will get to know how some of the basic DAQ systems 1.1 can looks
like. In the scope of the diagnostic in mechanical engineering, one must use different kind of
sensors to investigate different kind of phenomena.
The measurement of a physical phenomenon, such as the temperature begins with a sensor. A
sensor, also called a transducer, converts a physical phenomenon into a measurable electrical
signal. Depending on the type of sensor, its electrical output can be a voltage, current, resistance, or another electrical attribute that varies over time. Some sensors may require additional
components and circuitry to properly produce a signal that can accurately and safely be read
by a DAQ device.
DAQ hardware acts as the interface between a computer and signals from the outside world. It
primarily functions as a device that digitizes incoming analog signals so that a computer can
interpret them. The three key components of a DAQ device used for measuring a signal are
the signal conditioning circuitry, analog-to-digital converter (ADC), and computer bus. Many
DAQ devices include other functions for automating measurement systems and processes. For
example, digital-to-analog converters (DACs) output analog signals, digital I/O lines input and
output digital signals, and counter/timers count and generate digital pulses.
Signals from sensors or the outside world can be noisy or too dangerous to measure directly.
Signal conditioning circuitry manipulates a signal into a form that is suitable for input into an
ADC. This circuitry can include amplification, attenuation, filtering, and isolation. Some DAQ
devices include built-in signal conditioning designed for measuring specific types of sensors.
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CHAPTER 1. USE OF VARIOUS DAQ EQUIPMENT
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A computer with programmable software controls the operation of the DAQ device and is used
for processing, visualizing, and storing measurement data. Different types of computers are used
in different types of applications. A desktop may be used in a lab for its processing power, a
laptop may be used in the field for its portability, or an industrial computer may be used in a
manufacturing plant for its ruggedness.
Figure 1.1: Parts of DAQ system.
In the scope of this exercise students will have five different measurement stations, where they
will operate with a turbine flow meter, a hygrometer, a pressure transducer, RTD Pt100 sensors
and a high-speed camera.
CHAPTER 1. USE OF VARIOUS DAQ EQUIPMENT
1.2
3
Flow measurement
Equipment provided:
• Water flow meter - turbine,
• DAQ device (NI USB 6001),
• Computer with NI software (NI MAX and LabView),
• Power generator,
• Digital scales and 10L reservoir,
• Cables.
Student tasks:
• Connect sensor (flow meter) with DAQ device, power supply and computer,
• Connect flow meter with the tap pipe and drain,
• In NI MAX test if the sensor is connected correctly,
• Calibration: through the flow meter pour 5 to 10 L of water into the reservoir provided
and measure its mass. With NI MAX one can define the number of pulses for 1L of poured
water. Signal output from the sensor is in pulses.
• After calibration open the program Flowmeter.vi in LabView (provided on the desktop).
Set the correct coefficient into the program and once again pour 5 to 10L of water into the
reservoir (during this filling one shoud changes the flowrate). Record the data and save
them into a .txt file. At the end of the recording measure the mass of the poured water
with the scales.
• Compare the measured mass of water with the calculated mass or volume with saved data.
• Draw shematic DAQ system.
CHAPTER 1. USE OF VARIOUS DAQ EQUIPMENT
1.3
4
Relative humidity measurement
Equipment provided:
• Humidity sensor HIH 5031,
• DAQ device (NI USB 6001),
• Computer with NI software (NI MAX and LabView),
• Power generator,
• Cables.
Student tasks:
• Connect humidity sensor with DAQ device, power supply (carefully 5V is max voltage
supply) and computer,
• In NI MAX test if the sensor is connected correctly (one can use 3,3VDC supply and
diagram provided in technical specifications),
• Open the program Relative humidity.vi in LabView (provided on desktop). Run the program and measure the RH of the air for 5-10 seconds, than blow some air from your nose
and mouth on the sensor. At the end put the sensor into the glass yar with saturated salt
solution and leave it closed for at least 5-10min. Signal from the sensor is in volts, which
means you have to calculate the values into the right units and also make a compensation
based on temperature measurements.
• Draw shematic DAQ system.
CHAPTER 1. USE OF VARIOUS DAQ EQUIPMENT
1.4
5
Pressure measurement
Equipment provided:
• ABB 266AST pressure transducer,
• DAQ device (NI USB 6210),
• Computer with NI software (NI MAX and LabView),
• Power generator,
• Cables, resistor.
Student tasks:
• Connect pressure transducer with DAQ device, power supply and computer. The output signal from pressure transducer is current (4-20mA). DAQ device can only measure
voltage...use resistor in order to measure voltage with DAQ device.
• In NI MAX test if the sensor is connected correctly,
• Open program Pressure.vi in LabView (provided on desktop). In order to get the signal
on the diagrame in units kPa, one must calculate the correct coefficient K and constant N
in formula y = Kx + N .
• Blow into the tube connected to the sensor and measure your lungs pressure. Save the
data.
• Draw shematic DAQ system.
CHAPTER 1. USE OF VARIOUS DAQ EQUIPMENT
1.5
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Temperature measurement
Equipment provided:
• 2x Pt100 temperature sensors and thermocouple K-type,
• Agilent DAQ unit with 20 channel multiplexer (2/4 wire) module connected to the electrical enclosure,
• boiling water and ice bath.
Student tasks:
• Connect all three RTD sensors into the elecrtical enclosure,
• Set on Agilent for all three selected channel right configuration. To set the configuration
select the channel with a rotating knob and button ”measure”.
• Calibrate all three temperature sensors with ice bath and boiling water (based on the
pressure in the laboratory calculate the boiling temperature of the water). Compare the
results.
• Both Pt100 sensors are 4-wire sensors, buth they can also be connected by only 2-wire.
Compare 2 or 4-wire connection.
• Draw shematic DAQ system.
CHAPTER 1. USE OF VARIOUS DAQ EQUIPMENT
1.6
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Visualization
Equipment provided:
• High-speed camera Fastec HiSpec4, with 50mm lens,
• Computer with HiSpec software,
• 2x high power LEDs light for illumination with power supply. CAUTION - DO NOT
LOOK DIRECTLY INTO THE LIGHT
Student tasks:
• Connect camera with power supply and computer,
• Open HiSpec software and connect the camera,
• Select ROI (region of interest),
• Select frame rate and shutter time,
• Set the LEDs for optimal illumination,
• Record the phenomena and save approximatelly 0,1s of data in bmp or jpg format,
• Draw shematic DAQ system.