VC and VR Series Humidity / Temperature Sensors: Compact Measurement Solutions for Demanding Environments
Accurate humidity and temperature measurement is essential in industrial processes, HVAC systems, storage areas, laboratories, drying applications, building materials and environmental monitoring. In many applications, the sensor must be compact, durable and suitable for difficult operating conditions.
The MELA® VC and VR Series Humidity / Temperature Sensors are designed for reliable measurement of relative humidity and temperature in air and other non-aggressive gases. With their rod-shaped compact design, high-grade stainless steel sensor housing and multiple output options, these sensors provide a flexible solution for demanding measurement applications.
What Are the VC and VR Series?
The VC and VR series are compact humidity and temperature sensors developed for a wide range of applications. They are especially suitable for use in extreme conditions where stable measurement, robust construction and long service life are required.
The VC series is supplied with a 1.5 m connecting cable, making it practical for direct installation and wired connection. The VR series is supplied with a robust aluminum connecting head and terminal screws, offering a more industrial field connection structure.
Both series are used for measuring relative humidity and temperature in air and other non-aggressive gases.
Designed for Extreme Conditions
The VC and VR series have been developed for challenging operating environments. Their compact rod-shaped construction and high-grade stainless steel sensor housing make them suitable for industrial use.
The catalog highlights the advantages of the .../9 series, which offers improved dynamic response, especially at low air speeds. This version also provides increased service life in more demanding operating conditions, including pollutant impact or permanent humidity above 95% RH.
However, when air speeds are extremely high and combined with a high particle load, the .../9 series is not recommended.
Humidity Measurement Performance
The relative humidity output has a measuring range of 0–100% RH. Accuracy is specified as ±2% RH in the measuring range of 5–95% RH at 10–40 °C.
For temperatures below 10 °C or above 40 °C, the additional temperature influence is specified as 0.1% / K.
This makes the VC and VR series suitable for applications where reliable humidity monitoring is required across a broad measurement range.
Temperature Measurement Performance
For temperature measurement, the sensors use a Pt100 Class B measuring element according to DIN EN 60751.
The temperature measuring range is -30 °C to +70 °C. Depending on the selected output type, the accuracy is specified as approximately ±0.2 K for voltage outputs, while the 4–20 mA version has accuracy depending on air speed.
This combination of humidity and temperature measurement allows the sensors to support both process monitoring and environmental control applications.
Flexible Output Options
The VC and VR series are available with several analog output configurations.
For humidity-only measurement, output options include 4–20 mA, 0–10 V and 0–1 V.
For humidity and temperature measurement, the series offers passive temperature output versions with Pt100, as well as active temperature output versions. Available combined options include 4–20 mA + Pt100, 0–10 V + Pt100, 0–1 V + Pt100, 2 x 4–20 mA, 2 x 0–10 V and 2 x 0–1 V.
This wide output selection makes the sensors easy to integrate into PLC systems, controllers, data loggers, HVAC systems and building automation equipment.
VC Series: Cable Connection for Practical Installation
The VC series is supplied with a 1.5 m connecting cable. This makes it suitable for installations where a ready cable connection is preferred.
The cable version is practical for compact equipment, ducts, machines and measurement points where the sensor can be wired directly to the control system.
VR Series: Connecting Head for Industrial Use
The VR series is equipped with a robust aluminum connecting head and terminal screws. This structure supports more flexible field wiring and is useful in industrial installations where terminal-based electrical connection is preferred.
For the VR series, the catalog recommends using a screened cable to maintain interference immunity according to EN 61326. The cable should be fitted into the sensor’s EMC conduit thread by qualified personnel.
Protection and Operating Conditions
The electronics have a protection class of IP65. The degree of protection of the sensor head depends on the selected filter.
With the ZE13 sintered high-grade steel filter, the sensor head protection is IP65. With the ZE04 filter, the protection class is IP20.
The ambient temperature range is -40 °C to +80 °C, allowing the sensor to be used in demanding environmental conditions when installed correctly.
Filter Options
The series can be supplied with different filter versions according to the application.
The x=5 version uses the ZE13 sintered high-grade steel filter. This option is suitable for robust applications and is also recommended for equilibrium humidity measurement in bulk materials and brickwork.
The x=9 version uses an integrated PTFE element filter and the ZE04 high-grade steel filter. This version provides improved dynamic behavior and longer service life under challenging humidity and pollutant conditions.
Equilibrium Humidity Measurement
The VC and VR sensor design is also suitable for equilibrium humidity measurements in bulk materials and brickwork, especially with the .../5 series.
For this type of application, the sensor head is inserted sufficiently into the material and sealed to prevent influence from ambient room humidity. The measured relative humidity then represents the equilibrium humidity of the material and can be used as an indication of material moisture.
This makes the sensors useful not only for air measurement but also for monitoring moisture behavior in construction materials and bulk goods.
Installation Recommendations
Correct installation is important for accurate measurement. The sensor should be installed in a location where representative humidity levels occur.
Installation near heaters, windows or outside walls should be avoided, because these locations may not represent the actual room or process humidity.
The sensor can be installed in any position, but positions where water can enter should be avoided. Dew formation and splashes do not normally damage the sensor, but measurement readings may be incorrect until moisture around the filter has dried.
Air Speed and Self-Heating Considerations
For VC and VR sensors, the specified minimum air speed and operating-voltage-adapted current output load should be observed. If these requirements are not met, additional measurement errors may occur due to sensor self-heating.
The minimum air speed depends on the output type. For example, 2 x 4–20 mA versions require at least 1.5 m/s, while 0–10 V and 2 x 0–1 V versions require lower minimum air speeds.
Clocked operation can help reduce self-heating effects in some applications.
Maintenance and Cleaning
Dust does not normally damage the humidity sensor, but it can slow down dynamic response. If too much dust accumulates, the protective basket can be carefully unscrewed and rinsed.
During cleaning, the sensitive sensing element must not be touched. The sintered protective basket must be completely dry before being reinstalled, otherwise measurement errors may occur.
This makes proper maintenance important for preserving long-term measurement performance.
Typical Application Areas
The VC and VR series can be used in HVAC systems, industrial air monitoring, drying systems, environmental chambers, storage rooms, process equipment, laboratories, building monitoring and non-aggressive gas applications.
They are also suitable for equilibrium humidity measurement in bulk materials and brickwork when the correct filter version is selected.
Why Choose VC and VR Series Sensors?
The VC and VR series are strong choices when compact design, durable construction and flexible output options are required.
The stainless steel sensor housing, broad humidity range, Pt100 temperature measurement, multiple analog outputs and filter options make the series adaptable to different process and environmental conditions.
VC is practical when a cable-connected sensor is preferred. VR is better suited for installations requiring a robust connecting head and terminal wiring.
Conclusion
The VC and VR Series Humidity / Temperature Sensors provide compact and reliable measurement for relative humidity and temperature in air and non-aggressive gases. With high-grade stainless steel sensor construction, IP65 electronics protection, multiple output options and versions for demanding humidity conditions, the series offers flexible solutions for industrial and environmental applications.
For users who need accurate humidity and temperature monitoring in compact, robust and configurable sensor formats, the VC and VR series provide dependable performance across a wide range of applications.