Dew Point Sensor Manufacturer

HENGKO® HT608 Dew Point Sensor

Industrial Dew Point Sensors for Environmental Monitoring


The compact HT-608 dew point transmitter with a measuring range down to -60 °C (-76 °F) Td and outstanding price/performance ratio is dedicated for applications in compressed air systems, plastic dryers and industrial drying processes.


  • Dew point sensor for compressed air
  • Output Modbus/RTU
  • NEW Weatherproof, dustproof, and water-resistant—IP65-rated enclosure
  • Fast response precision sensors provide accurate, repeatable readings
  • Dew Point Sensor / Transmitter for Industrial Drying Processes
  • -60°C OEM dew point sensor
  • High pressure option for 8KG


♦ Special mini and integrated temperature & humidity sensor module. Easy to
install and convenient for system networking and wiring.
On-board CR2450 wide warm button battery, external power still ensures the
normal operation of the module, no data loss
Integrated large-capacity flash chip, allowing storage of up to 65,000 records,
meeting long-term recording needs.
Ultra-low power consumption design, when powered by the onboard button
battery, the average power consumption is only tens of microamperes.

Adopting HENGKO RHT temperature and humidity sensor, high acquisition
accuracy, and good consistency.
Adopting standard Modbus-RTU, It can easily realize the interface between
PLC, man-machine screen, DCS, and various configuration software.
Communications Protection: RS485 communication signal output interface
adopts double over-voltage and over-current protection.
4.5V~12V extra wide voltage input.

Output temperature and humidity, dew point temperature, wet bulb
It can download and analyze the data via Smart Logger software
Power polarity protection, has an anti-reverse connection function.
dew point sensor for compressed air




Technical Specifications


DC 4.5V~12V



Measurement range











Long-term stability

humidity<1% RH/Y  temperature<0.1℃/Y

Dew point range:

-60~60℃(-76 ~ 140°F

Response time

10S(wind speed 1m/s)

Communication interface


Records and Software

65,000 records, with Smart Logger professional data management and analysis software

Communication band rate

1200, 2400, 4800, 9600, 19200, 115200(can be set), 9600pbs default

Byte format


8 data bits, 1 stop bit, no calibration



Step 1: Choose Models

pressure dew point meter

Basic  G 1/2"

This economical, compact dew point sensor is suitable for refrigerant, desiccant, and membrane dryers.

Handheld temperature and humidity insert ground type DSC_4454-1
HT-608 c

Extra Small Diameter

Measurements in small holes and narrow passages.

HENGKO-Temperature and humidity measurement instrument -DSC 7271
HT-608 d

Pluggable and exchangeable

An ideal everyday spot-checking tool. It is compact, portable, and provides reliable measurements in a wide range of applications.


Step 2: Choose a Suitable Probe Housing


Click model to download cutsheet

Metal microporous filter element -DSC 1867
HENGKO-sht20 i2c temperature & humidity sensor probe housing- DSC_8872
Flat top
HENGKO-Soil temperature and humidity sensor probe protection case DSC_7180
Temperature humidity waterproof housing -DSC 2884



T&H Logger Tools

  • Powerful desktop software for displaying measurement data in real-time. No internet connection is required.

    Simple, intuitive user interface
    It can be realized through RS485 to USB


Used to realize the recording function: select the timing start as the start mode under the record category of the test software, set the start time and sampling interval, and click Set and Read

Download data: You need to close the test software and then open the Smartlogger software, click the download button (if there is no response) to close the download, and try to click File to download data



What is dew point? What is it related to?

The dew point is the temperature at which the unsaturated air lowers its temperature while keeping the partial pressure of water vapor constant (that is, keeping the absolute water content constant) so that it reaches saturation. When the temperature drops to the dew point, condensed water droplets will be precipitated in the humid air. The dew point of humid air is not only related to temperature, but also related to the amount of moisture in the humid air. The dew point is high with high water content, and the dew point is low with low water content. At a certain humid air temperature, the higher the dew point temperature, the greater the partial pressure of water vapor in the humid air, and the greater the water vapor content in the humid air.


Measuring dew point in industrial settings is critical to ensuring that sensitive equipment does not undergo corrosive damage and the quality of end products is preserved.

Why measure dew point?

Have you ever had a failing dryer in your compressed air system, ruining your production output, but it was not noticed until it was already too late? Dry compressed air is one of the most important quality parameters when it comes to process safety. When ambient air is compressed, the ratio of the humidity to the air volume will rise drastically. Therefore the higher concentration of humidity in the compressed air leads to a higher dew point temperature and the humidity is more likely to condensate at higher temperatures. What can be worse than having water droplets in the compressed air piping, which can lead to machinery breakdown, contaminating your process or even cause blockages?

Using an instrument to measure dew point, a so-called dew point analyzer or dew point meter, will help users to operate a safe and reliable compressed air system, notifying them early in case of alarms.

What is the difference between "dew point" and "pressure dew point"?

The so-called "pressure dew point" refers to the dew point temperature value measured in an environment higher than atmospheric pressure, that is, the dew point temperature of the gas under pressure. This is important because changing the gas pressure changes the dew point temperature of the gas.

How does pressure affect dew point?

Under the condition of constant temperature and confined space, the dew point increases with the increase of pressure, and the dew point decreases with the decrease of pressure (up to atmospheric pressure), which is the influence of dew point and pressure.
Since all dew point meter moisture measurements are derived from the measurement of water vapor pressure, the measurement of the total gas pressure of the system will have an impact on the measured humidity.

Why is it important to know the dew point of compressed air?

The importance of dew point temperature to compressed air depends on its use, and in many cases dew point is not a determining factor, such as hand-held compressors in air tools, tire inflation systems in gas stations, etc.). The dew point only becomes important where the pipes carrying the air are exposed to condensing temperatures, at which point a high dew point can cause the pipes to freeze and block. Compressed air is used in many modern factories to operate a variety of equipment, some of which can malfunction if water vapor condensation forms on internal parts. Certain water-sensitive processes (such as painting) that require the use of compressed air may have specific specifications for dryness. There are also medical and pharmaceutical processes that consider water vapor and other gases to be contaminants, requiring very high levels of purity.

What should be paid attention to when measuring the dew point of compressed air with a dew point meter?

Use a dew point meter to measure the air dew point, especially when the water content of the measured air is extremely low, the operation must be very careful and patient. Gas sampling equipment and connecting pipelines must be dry (at least drier than the gas to be measured), the pipeline connections should be completely sealed, the gas flow rate should be selected according to regulations, and a long enough pretreatment time is required. If you are careful, there will be big errors. The practice has proved that when the "moisture analyzer" using phosphorus pentoxide as the electrolyte is used to measure the pressure dew point of the compressed air treated by the cold dryer, the error is very large. This is due to secondary electrolysis generated by the compressed air during the test, making the reading higher than it actually is. Therefore, this type of instrument should not be used when measuring the dew point of compressed air handled by a refrigerated dryer.

Where should the pressure dew point of compressed air be measured in the dryer?

Use a dew point meter to measure the pressure dew point of compressed air. The sampling point should be placed in the exhaust pipe of the dryer, and the sample gas should not contain liquid water droplets. There are errors in the dew points measured at other sampling points.

What are the compressed air drying methods?

Compressed air can remove water vapor in it by pressurization, cooling, adsorption and other methods, and liquid water can be removed by heating, filtration, mechanical separation and other methods.

The refrigerated dryer is a device that cools down the compressed air to remove the water vapor contained in it and obtain relatively dry compressed air. The rear cooler of the air compressor also uses cooling to remove the water vapor contained in it. Adsorption dryers use the principle of adsorption to remove water vapor contained in compressed air.

What impurities are contained in compressed air?

The compressed air discharged from the air compressor contains many impurities: ①Water, including water mist, water vapor, condensed water; ②Oil, including oil stains, oil vapor; ③Various solid substances, such as rust mud, metal powder, rubber Fines, tar particles, filter materials, fines of sealing materials, etc., in addition to a variety of harmful chemical odor substances.

What are the hazards of impurities in compressed air?

The compressed air output from the air compressor contains a lot of harmful impurities, the main impurities are solid particles, moisture, and oil in the air.

Vaporized lubricating oil will form an organic acid to corrode equipment, deteriorate rubber, plastic, and sealing materials, block small holes, cause valves to malfunction, and polluting products.

The saturated moisture in the compressed air will condense into water under certain conditions and accumulate in some parts of the system. These moistures have a rusting effect on components and pipelines, causing moving parts to be stuck or worn, causing pneumatic components to malfunction and air leakage; in cold regions, moisture freezing will cause pipelines to freeze or crack.

Impurities such as dust in the compressed air will wear the relative moving surfaces in the cylinder, air motor and air reversing valve, reducing the service life of the system.

Why is compressed air widely used in industry?

Storage: Easily store large volumes of compressed air as needed.

Simple Design and Control: Acting pneumatic components are of simple design and are therefore suitable for simpler controlled automatic systems.

Choice of motion: Pneumatic components are easy to realize linear and rotary motion with stepless speed regulation.

Compressed air generation system, because the price of pneumatic components is reasonable, the cost of the whole device is low, and the life of pneumatic components is long, so the maintenance cost is low.

Reliability: Pneumatic components have a long working life, so the system has high reliability.

Harsh environment adaptability: Compressed air is not affected by high temperature, dust and corrosion to a large extent, which is beyond the reach of other systems.

Clean environment: The pneumatic components are clean, and there is a special exhaust air treatment method, which has less pollution to the environment.

Safety: It will not cause fire in dangerous places, and if the system is overloaded, the actuator will only stop or slip.

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