Possibly you are right now collecting information about temperature sensors for your machinery. You may know what your role is, but it's not yet clear what types of temperature sensors exist. Knowing the types of temperature sensors will help you to know which is the most appropriate when installing one of these systems in your company.
Therefore, in the following post we will solve all your doubts: what types of temperature sensors exist, what are the differences between a thermostat and a temperature sensor and which of these sensors is the most recommended and used at this time.
Stay with us to resolve all these issues. Let's start:
What is a temperature sensor?
A temperature sensor is a system that detects variations in air or water temperature and transforms them into an electrical signal which reaches an electronic system. This signal entails certain changes in that electronic system for temperature regulation.
Also known as temperature probe, This sensor is mainly composed of three parts. First of all, and obviously, it has a sensor element (whose types we will see in this post). In addition to this element, it is made up of a sheath of conductive material inside and a cable that connects to the electronic system in question.
Once you understand a little better how the temperature control through these systems, it is time to move on to see the types of temperature sensors that exist today.
What types of temperature sensors are there?
Depending on their operation and the way in which they transform the signal, there are different types of temperature sensors. Mainly, they are three categories: RTD sensors (PT100, PT1000, Thermistors) thermocouples and infrared
Now we will see in detail these types of temperature sensors, in which it is possible to find different variants:
Thermocouples, the most used
The thermocouple is the most widely used sensor. in temperature measurement systems. These economic sensors, easy to install and with a precision adjusted to different processes. Although its operation is sufficient, its response can be somewhat slow compared to other types of temperature sensors.
The operation of thermocouples is based on two metallic threads of different materials joined at one end, which is known as a hot junction or measurement junction. It has another separate end, called a cold joint. The temperature difference between the two joints produces a voltage differential, which will be the signal sent to the electronic device.
Within these sensors, there are different types of thermocouples depending on the materials they are made of. The most common are the following:
- J Type Thermocouple: Made of a combination of iron and state (alloy of copper and nickel). Limited use in oxidizing environments. It has a temperature range between 0°C and 750°C.
- T Type Thermocouple: It is made up of a copper wire and a constant one. Recommended for use in humid environments. Its temperature range is between -250°C and 350°C.
- K Type Thermocouple: Composed of a chromega (chrome and nickel alloy) and alomega (aluminium and nickel alloy) joint, it is the most widespread temperature capture system. And it is that its temperature range is very wide, being between -200°C and 1250°C, although it is recommended for measurements between 300 and 1100ºC.
- Type E Thermocouple: Its combination of materials include chromega and state. Its temperature range is between -200°C and 900°C.
In addition to these four common forms of thermocouples, there are many other variants. Notable are the formats for high temperatures, such as the Type S Thermocouple (between 0°C and 1650°C) or the Type R Thermocouple (between 0°C and 1750°C).
PT100 and PT1000
This type of sensor bases its operation on the temperature resistance of the material of which it is composed. Its general structure is usually composed of a tightly wound wire with a glass or ceramic core around it or stratified ceramic.
These temperature sensors are especially suitable for measurement in industrial environments, thanks to their immunity to electrical noise. Among the main materials with which they are usually built, are platinum and nickel.
these RTD sensors They are mounted inside different metal or plastic constructions tailored to each machine.
PT100, the most suitable sensor
Within all the variants and types of temperature sensors, you are surely wondering which of them could be considered the best. Everything will depend on the measurement needs and the environment to be controlled, but without a doubt, there is a sensor that should always be considered as the first option: PT100 sensor.
The pt100 is a RTD type temperature sensor, with a wide range of temperatures, located between -200°C and 850°C. His name refers to the 100 ohms showing at 0°C. Its resistance increases as the temperature increases and its precision will depend on the model that is mounted (Din-B, Din-A, 1/3Din or 1/10Din)
NTC and PTC thermistors
Within the types of temperature sensors, thermistors stand out for their operation. And they are composed of semiconductor materials whose resistance to temperature varies depending on the degrees of the same. Its internal electrodes detect heat, measuring it by electrical impulses.
Thermistor temperature control also has variants. Thus, we can find the following types of thermistor according to its operation:
- NTC thermistor. The use of a NTC temperature sensor It is especially indicated in wide ranges of temperatures. The higher the temperature, the less resistance. They are usually made of magnesium, copper, nickel or cobalt.
- PTC thermistor. These sensors are indicated for drastic changes in resistance and temperature that you want to control. In this case, the higher the temperature, the greater the resistance. They are mainly made of barium titanium.
Non-contact infrared sensors
Infrared sensors are suitable for high-performance measurements of inaccessible or moving objects and materials.
Temperatures from -20ºC to 2000ºC can be measured. 4-20mA or thermocouple output, compatible with a wide variety of instrumentation available in this catalog without the need for an interface or special signal conditioning. There are several versions depending on the optical resolution to measure all kinds of objects.
Sensors are fully configurable from a PC using easy-to-use software included with each unit. The user can set the range and emissivity, apply filters, select minimum, maximum, average and instantaneous readings... In addition, it is capable of operating in temperature environments of up to 50ºC, while there is a version with a water-cooled casing and a an air purge collar for more adverse conditions.
Differences between thermostat and temperature sensor
Once we have been able to contemplate the most common types of temperature sensors, we want to make a turning point when talking about these systems. And, on many occasions, there is a tendency to confuse temperature sensor with thermostat.
He thermostat is a system whose goal is create an alert when a certain temperature is reached. A continuous temperature measurement is not used to monitor certain conditions, but a certain temperature is marked for enable or disable certain features.
For their part, and as we have seen throughout this post, the thermometers yes they are used for control a series of conditions through constant measurement and detailed.
Once we have done this review of the most common types of temperature sensors, it is time to go to the best place to get the most suitable sensor for your application.
At SRC we are producers of thermometers . we have 42 years of experience in measuring, regulating and controlling industrial parameters. This gives us the know-how to become your reference company for everything that has to do with your company's temperature sensors.
Contact us if you have doubts about the types of temperature sensors that are best for you. We will be happy to assist you at all times.