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Using labview to measure temperature with a thermistor

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Thermistor

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Download PDF. You will do This way Briscoe and W. Your setup may have slight differences. Introduction The purpose of the exercise is to give you some experience using LabVIEW for automatic, computer-based data collection from an experiment.

You will be measuring the internal temperature of a grape or similar object as a function of time as it is plunged into a glass of ice water. Using the collected data, you will determine the time constant of the heat transfer dynamics that model the temperature drop. What You Will Need 1. USB cable 4.This is an online, interactive lab that contains instructions, multimedia, and assessments where students can learn at their own pace.

As an instructor, you can create and edit instances of this lab, assign them to students, and view student progress. This is an online, interactive course that contains instructions, multimedia, and assessments where students can learn at their own pace. As an instructor, you can create and edit instances of this course, assign them to students, and view student progress. Learn more.

LabVIEW is systems engineering software for applications that require test, measurement, and control with rapid access to hardware and data insights. Includes sensors and components needed for basic projects. Students have the opportunity to engage in custom projects to learn sensor and actuator integration and basic programming. These labs have related concepts that can expand student experience.

Manage Library. New Course. Back Take Training. This project introduces students to the thermistor principles of operation, measurement of thermistor resistance, conversion of measured resistance to temperature, and sizing of the voltage-divider resistor for the best measurement sensitivity and range.

Students complete activities that demonstrate component operation and interface theory so that students can use thermisters in future integrated projects. Through these activities, students follow steps to demonstrate correct operation of the thermistor, watch videos involving theory, and participate in a short activity after each video.

Download Lab Bookmark. Related Resources.Forgot Password? Create an Account. Each device provides analog input along with digital and counter functions, and cold junction compensation CJC. Available with support for thermocouple, RTD, thermistor, and semiconductor sensors. The product works well for our intended purposes. Was this review helpful? Product is ideal for our optical usage.

Very convenient to have one product to support multiple sensor types. Conversions are accurate and surprisingly noise free. Also love the Linux support. Wish list: one current source per channel, option for general analog input. Easy to set up and use. Straight forward configuration.

using labview to measure temperature with a thermistor

Been using for many years. We had to do a lot of software filtering for our application. It would be awesome if they can incorporate a hardware filter. I used this device in conjunction with ROS.

Provides accurate measurements at a good cost. Product works great in a flow measurement application.

Thermistor Measurements With the NI-9219 and Other C Series Modules

The included libraries made it easy to write a custom app in VB. I have purchased a couple of these DAQs now; they have all had excellent build quality and are easy to use with the DAQami software which is also a great deal. This model makes it very easy to log thermocouple data no post amplification or filtering required and any other voltage based sensors via the analog inputs.

The cost is great in comparison to comparable DAQs from NI etc that require much more expensive programming to use effectively.

We have developed a little. It works great, and we rarely have to reboot our system. The device itself doesn't overheat and it is easy to install. The only issue we have had with it is that on very powerful Kansas thunderstorms, we get some static that blow the device sensors, but I think this has to do a lot with the kind of connectors that were initially installed. Measurement Computing customer support is great and I can always get one of their techs live on the phone.

This item is both cost effective, and powerful to implement in a control system compared to other alternatives. I have a 24V proximity NPN sensor. I wan't to monitor the sensor with one of the DIO line using simple voltage divider, is it possible to open the box and remove a single pull-up resistor? You could consider leaving the internal circuit 47K pull-ups as-is, and selecting fairly low resistor values for your external voltage divider.

In any case, take care not to apply greater than 5. Field modifications, if done improperly, would void the warranty. All 8 of the pull-up resistors are in one surface mount resistor network, which may be challenging to remove. There is a 0-ohm surface mount resistor which would be easier to remove.

Was this answer helpful? Is there some calibration or configuration which I have not done correctly? The only configuration required is to set the direction of desired bits to output since they default to inputbut this is done for you in the ULx for LabVIEW driver. Be sure to tighten down the screw terminals, since the tops of the screws do not make electrical contact with the internal circuitry until they are screwed down.Have you ever wondered how some devices like thermostats, 3D printer heat beds, car engines, or ovens measure temperature?

With this project, you can find out! Knowing the temperature in a project can a very useful piece of data to have handy. For this article, we are only concerned with one type of sensor that can measure temperature. This sensor is called a thermistor.

A thermistor exhibits resistance that is far more sensitive to temperature than that of other types of resistors. We will use an Arduino to measure and process the reading from a thermistor and then convert this into a human-friendly format of common temperature units.

How to use LM335 Temp Sensor

If this were not the case, resistors would make weird things happen in circuits, such as an LED that gets much brighter and dimmer as the ambient temperature changes. This is where the thermistor comes in. As you might have guessed, a thermistor has a large change in resistance with a small change of temperature. To illustrate this concept, check out a typical curve of a thermistor:. The units are shown but not the actual values as a thermistor can tailor to different ranges depending on which you buy.

As you can see, the temperature gets hotter, the resistance is lower. However, PTC thermistors have a sort of tipping point and greatly change the resistance at some temperature. This makes the PTC thermistor a little harder to interface with. The curve in the graph above is non-linear and, therefore, a simple linear equation does not seem possible.

In reality, we can work out an equation, but more on this later. Before reading on, think about how you would do this in the Arduino or even a circuit without a microprocessor component.

There are a few ways you can approach this problem, listed below. This is by no means a list of every technique out there, but it will show you some popular approaches.

using labview to measure temperature with a thermistor

Some manufacturers are nice enough to give you an entire chart mapping a certain integer range of temperature and resistance typical values. One such thermistor can be found on this datasheetby the company Vishay.

But then you think how you would do this in the Arduino. You would need to hard code all of these values into the code in a huge lookup table or a very long "switch…case" or "if…then" control structures. And if the manufacturer is not nice enough to give a lookup table, you need to measure each point yourself to generate the data.The content is shown in another available language.

Your browser may include features that can help translate the text. The NI can be used for thermistor measurements, although this is not a recommended configuration. The module was not specifically designed for thermistor measurements so there may be limitations affecting measurements accuracy. This is because it was never tested with thermistors and the accuracy hasn't been characterized across the entire possible thermistor range.

There are two configurations for measuring a thermistor with the NI The 2-wire resistance measurement configuration is easier to assemble than the half-bridge configuration, but it does not take into account measurement accuracy. Please check the Resistance Measurement Range to make sure the card is capable of measuring your sensor's resistance range.

A Voltage Input module can help you measure sensors that operate changing their resistance, such as Thermistors. There are some strategies you can take, depending on the characteristics of the circuit you are designing:. This content is not available in your preferred language. Reported In. Reported In shows products that are verified to work for the solution described in this article.

This solution might also apply to other similar products or applications. Other Thermistors. What C series options are available to measure thermistors? Can the NI be used for thermistor measurements? Is this configuration recommended or officially supported? I'm using the NI for thermistor measurements and getting a temperature measurement that is slightly off. What could be causing this accuracy issue? This is the first limitation.To browse Academia.

Skip to main content. Log In Sign Up. Briscoe and W. Your setup may have slight differences. Introduction The purpose of the exercise is to give you some experience using LabVIEW for automatic, computer-based data collection from an experiment. You will be measuring the internal temperature of a grape or similar object as a function of time as it is plunged into a glass of ice water.

Using the collected data, you will determine the time constant of the heat transfer dynamics that model the temperature drop. What You Will Need 1. USB cable 4. Thermistor temperature sensor NTC, 10K ohms, jameco. Digital multi-meter that can read resistance 6. Solderless breadboard 7.

A 10K ohm resistor 9. A grape, or other small fruit, at room temperature In order for Equation 1 to work, absolute temperatures Kelvin units must be used. The thermistor used in this project, jameco. Hint: squeeze the DMM leads hard against the thermistor leads for an accurate resistance reading. See how close the measured value of R is to the theoretical value from Equation 1.

You may see the resistance measurement drifting due to self-heating from the current through the thermistor provided by the DMM. You will construct a voltage divider circuit to measure resistance. R1 is a 10K ohm resistor. R is the thermistor whose resistance varies with temperature. V is the output voltage that will be sampled by the data acquisition unit. For convenience, the output should be in Fahrenheit or Celsius. You will do this in two steps, first creating the conversion section then creating the data acquisition setting.

This way you can proceed with a good portion of the experiment setup without needing the data acquisition hardware. The indicator is a placeholder for the voltage reading that later will come from the data acquisition unit.

using labview to measure temperature with a thermistor

Your front panel will look something like this1 Save your VI.NTC Thermistors provide an excellent solution in applications requiring accurate temperature measurement.

If the user can measure the resistance electrically, solving for the temperature is easy with the resistance versus temperature curve that Ametherm provides for a specified NTC thermistor. However, if the thermistor is embedded in a circuit, the resistance changes are recorded in terms of the corresponding voltage or current changes.

A Wheatstone bridgealso called a null comparator, is used for measuring accurate resistance. When the potential voltage P1 see the figure is the same as potential P2, the bridge is said to be balanced.

For accurate measurement of R xthe Wheatstone bridge plays a great role, as the galvanometerin balanced condition, does not draw any power from the circuit. Although T is not a linear function of voltagefor small ranges in temperatures, it can be considered as linear and the error may be negligible in computing the temperature See Figure 3.

Thermistors are also subject to self heating effects that is not discussed here. Choice of resistors in the Wheatstone Bridge circuit depends on the application and on the temperature measurement range. Have a question? Ask an Engineer. Search for:. Thermistors for Temperature Measurement NTC Thermistors provide an excellent solution in applications requiring accurate temperature measurement. Figure 2. Figure 3: Typical voltage temperature curve from the bridge circuit Note: Thermistors are also subject to self heating effects that is not discussed here.


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