Humidity Sensors
Essential devices for measuring humidity levels in the air, humidity sensors guarantee a level of accurate monitoring necessary for a host of industrial, environmental, and domestic applications. These sensors function by detecting water vapor in the air—more precisely, they yield readings of relative humidity, which denotes the ratio of the amount of moisture in the air compared to the maximum amount it could hold at a given temperature. Among the most commonly used types of humidity sensors are humidity-capacitive sensors, which work in virtue of the electric properties of their internal elements. Changes in capacitance levels—that is, the ability of a material to store an electric charge—resulting from different moisture levels in the air yield high-fidelity digital outputs.
Humidity sensors offer an accurate measurement of both types of humidity, which are absolutely necessary for ensuring the energy efficiency and overall optimization of a wide array of industrial processes. Take, for instance, their use in HVAC systems. Here, humidity sensors serve a crucial role both in ensuring the total system functions as intended (i.e., uses the least amount of energy possible while maintaining the proper comfort conditions of temperature and humidity for the building occupants) and in providing a level of comfort.
More Information about Humidity Sensors
Adding humidity sensors to industrial and consumer equipment makes those systems more efficient and effective. Nowadays, you can find these tiny, inexpensive sensors in almost any "smart" device, from lightbulbs to thermostats to power strips. They're used to regulate not just the lighting but also the temperature and even the moisture content of the air in our homes. On a greater scale, smart control of all these variables in our indoor environments could improve energy consumption and cut greenhouse emissions.
FAQs
What is absolute humidity?
Absolute humidity is a measure of the total amount of water vapor present in a given volume of air. It is usually expressed in grams of water vapor per cubic meter of air (g/m³). This is unlike relative humidity, which is the ratio of the current amount of water vapor in the air at a given temperature to the maximum amount of water vapor the air could hold at that temperature, expressed as a percentage.
Is there a particular sensor that will measure the dew point, humidity and temperature?
Yes, there are sensors known as combined or multi-parameter sensors that can measure dew point, humidity, and temperature. One example of this is a capacitive humidity sensor.
How accurate is a temperature sensor at measuring the temperature of the surrounding air?
To accurately measure temperature of the surrounding air, will depend on the sensor type, sensor quality, calibration, environment and signal conditioning.
Analog and Digital Control Signals: The Basics
Digital Signals
Digital signals are represented in either a true or false. There is no gray area with digital signals. An example of this might be a light switch. A light switch is either on or off. Another example of this might be a motor that is running or not running. Digital signals can be generated with both AC and DC circuits with varying voltages, currents and resistance. Some practical examples of using digital signals in an industrial environment might be if a pump is running or not running or a whether a valve is open or closed.
Analog Signals
Analog signals convey information in the form of a range. A light switch might be on or off as a digital signal, but a dimmer switch would be an analog signal. It can be on or off, but it can also be somewhere in between. A practical example of using analog signals in an industrial environment would be if there is a need to measure the level of a tank; whether it's full, empty or somewhere in between. Analog signals can take many different forms with some of the more common being a 4 to 20 milliamp signal or a 0 to 5 or 0 to 10 volt signal.
Communication
Communication in a device can either be sent or received. Whether that data is sent or received depends on the type of information. Is there a need to monitor the status of something? If so, an input needs to be received about that information. Is there a need to control something? If so, an output needs to be sent about what needs to occur. Receiving inputs and setting outputs are both things that can be accomplished by using both digital and analog signal types. Therefore, the signals are referred to as analog outputs (AO), analog inputs (AI), digital inputs (DI) or digital outputs (DO).