Product description

Smart duct temperature and humidity sensor-controller | -30…70°C | 0-100%rH | 0-10VDC/0-20mA/PWM | Modbus RTU | 18-34VDC/15-24VAC | IP54 | Sentera Controls | DCTHG-2

DCTHG-2 – a Sentera Controls smart duct temperature and humidity sensor-controller: it measures temperature (-30…+70 °C) and relative humidity (0–100 % rH) in the duct and, using the integrated algorithm, generates one analog / modulating output (0-10 VDC, 0-20 mA or PWM) that can directly control an EC fan, an AC fan speed controller or a damper actuator. Supply – 18–34 VDC or 15–24 VAC ±10 %; all parameters are accessible via Modbus RTU.

Key idea:
This is a transmitter and a controller in one: it needs no separate controller, because the output is calculated in the sensor itself according to the set temperature and humidity ranges. The output is determined by the higher of the two values, and either parameter can be disabled – e.g. to control by temperature only or by humidity only.

Measurement
-30…+70 °C / 0–100 % rH

Control output
0-10 VDC / 0-20 mA / PWM

Power supply
18–34 VDC or 15–24 VAC ±10 %

Protection
housing IP54, probe IP20

Operating principle

The transmitter is mounted on the duct, the probe is inserted into the airflow (min. 1 m/s), and it is wired with 3 wires with a common ground: supply 18–34 VDC or 15–24 VAC (VIN, GND), control output AO1 and Modbus RTU (A, /B).

Integrated sensors measure temperature and relative humidity; a range is set for each quantity within which the output varies 0–100 %, the output is determined by the higher of the two calculated values, and either quantity can be disabled. The output type is selectable – 0-10 VDC (≥ 50 kΩ), 0-20 mA (≤ 500 Ω) or 1 kHz PWM (open collector, 3.3 or 12 VDC) – and it directly controls an EC fan, an AC fan speed controller or a damper actuator; all parameters are changed over Modbus RTU, and the firmware is updated over the network.

Result – demand-controlled ventilation without a separate controller: as the humidity or temperature of the extract air rises the fan speeds up, and when it falls it slows down to the minimum.

Benefits DCTHG-2?
Sensor and control algorithm in one – less equipment in the control panel, a simpler design and faster commissioning, while Modbus RTU allows later integration into a BMS.

Technical specifications

Product type	Smart duct temperature and humidity sensor-controller
Manufacturer / code	Sentera Controls / DCTHG-2
Series	DCTH-2 (DCTHF-2 / DCTHG-2 / DCTHM-2)
Measured quantities	Temperature, relative humidity
Temperature range	-30…+70 °C
Humidity range	0–100 % rH, non-condensing
Accuracy	±0.4 °C (-30…+70 °C); ±3 % rH
Control logic	Output based on the higher of the T and rH values; each parameter can be disabled
Analog output	1 × 0-10 VDC (RL ≥ 50 kΩ) / 0-20 mA (RL ≤ 500 Ω) / PWM 1 kHz, open collector, 3.3 or 12 VDC
Communication	Modbus RTU (RS485), A, /B; firmware update via Modbus RTU
Supply voltage	18–34 VDC or 15–24 VAC ±10 %
Max. current (Imax)	40 mA (DC) / 45 mA (AC)
Connection	3-wire, common ground (-G)
Min. air velocity	1 m/s
Protection class	IP54 housing, IP20 probe
Weight	0.16 kg (net)
Compliance	LVD 2014/35/EU, EMC 2014/30/EU, WEEE 2012/19/EU, RoHS 2011/65/EU

Manufacturer documentation

✔ Recommended by Elektrotechnikos sprendimai

Original manufacturer documentation – technical data, wiring diagrams and installation instructions.

Main functions

Integrated control algorithm – the output is generated according to the set T and rH ranges, without a separate controller.
Parameters that can be disabled – can be controlled by temperature only or humidity only.
Direct control – An EC fan, AC speed controller or damper actuator is connected directly to the output.
Modbus RTU – all parameters and measurements are accessible remotely; Modbus timeout (HR8) monitoring.
Firmware update – over the Modbus RTU network.
Configuration – Configuration and monitoring – the free Sentera 3SModbus software (via the CNVT-USB-RS485 converter) or the Sensistant Modbus configurator.

Where is it used?

Extraction ducts from bathrooms, showers and swimming pools
Humidity- and temperature-based ventilation in residential and commercial buildings
Warehouses, workshops
Systems with EC fans
BMS with Modbus RTU
Farm building extract ventilation ducts
Modernization of existing 24 VAC ventilation automation

On-demand operation

For farm building ventilation installers.
The -G version is powered from a 24 VAC transformer and controls the fan directly based on extract air T or rH.

For the modernizer of AC fan systems.
The output connects to the analog input of an AC fan speed controller, and no additional controller is needed.

For warehouse and workshop engineers.
The wide -30…+70 °C range allows ventilation to be controlled in unheated rooms as well.

Practical application

If the extract duct of a workshop has an AC fan with a speed controller and a 24 VAC supply, then the DCTHG-2 is wired with 3 wires and, based on extract air temperature or humidity, increases the fan speed with a 0-10 VDC signal.

Application guide: how it is used in practice

The same DCTHG-2 adapts to different sites – only what is connected to its output changes:

Site	What is connected	Result	Installer's note
Bathroom, shower, laundry	AO1 0-10 VDC → EC fan control input	As humidity rises, extraction automatically increases; when it falls, it returns to the minimum	Temperature can be disabled – control by rH only
Warehouse, workshops	AO1 → AC fan speed controller analog input	On a hot day extraction increases with temperature	Select the signal type according to the regulator input
System with an air damper	AO1 → damper actuator 0-10 VDC input	The damper opens in proportion to humidity or temperature	Check the actuator input resistance (≥ 50 kΩ for voltage mode)
Building with BMS	Modbus RTU → A, /B	Settings and status are accessible centrally	A separate address for each sensor

How to choose a duct temperature and humidity transmitter

Installation / output / power supply	Recommended model
Duct, 3 analog outputs (T / rH / T or rH), 18–34 VDC, 4 wires	DSTHF-3 (duct transmitter, -F)
Duct, 3 analog outputs, 18–34 VDC or 15–24 VAC, 3 wires	DSTHG-3 (duct transmitter, -G)
Duct, Modbus RTU only, Power over Modbus (PoM), RJ45	DSTHM-2 (duct Modbus transmitter)
Duct, direct fan / damper control with 1 output, 18–34 VDC	DCTHF-2 (smart duct sensor, -F)
Duct, direct control with 1 output, 18–34 VDC or 15–24 VAC	DCTHG-2 (smart duct sensor, -G) ← this model
Duct, control signal via Modbus RTU, PoM, RJ45	DCTHM-2 (smart duct sensor, PoM)

Rule: first decide where the measurement is made (duct, room, outdoors), then what you need from the transmitter: separate analog signals for a controller (transmitter, 3 outputs), data only to a BMS (Modbus / PoM version), or direct fan control with a single output (smart sensor). Finally – the supply and number of wires: -F – 24 VDC, 4-wire, separate grounds; -G – AC or DC, 3-wire, common ground; -M / -H – power over the Modbus cable (RJ45).

When to choose another solution: for measurement only with 3 analog outputs – DSTHF-3 / DSTHG-3; for Modbus-only measurement – DSTHM-2; when control by CO2 is also needed – DCMFG-2R.

Pros

Transmitter and controller in one
Control by T, rH or both
Accuracy ±0.4 °C, ±3 % rH
Modbus RTU, firmware updated over the network
0-10 VDC / 0-20 mA / PWM output
IP54 housing, -30…+70 °C

Cons / limitations

One control output – for separate T and rH signals choose a transmitter (RSTH-3 / DSTH-3)
IP20 probe, an airflow of ≥ 1 m/s is required
Must not be mixed with -F type products on the same network

Safety and installation notes

Installation and connection are to be carried out by a qualified electrician / automation specialist with the power disconnected.
Supply voltage – 18–34 VDC or 15–24 VAC ±10 %.
The -G version: 3-wire connection with a common ground (the analog output GND is connected to the supply GND). Never connect the common ground of the G version to devices powered by direct voltage (DC) – the connected devices may be damaged.
Do not mix -F and -G type products on the same network.
Resetting the Modbus communication parameters – with a jumper on PROG pins 1 and 2 for at least 5 s.
Install the probe in the airflow, away from humidifiers and condensate.

Quick selection guide

-30…+70 °C

0–100 % rH

0-10 VDC / 0-20 mA / PWM

Modbus RTU

18–34 VDC / 15–24 VAC

IP54

Suitable when you need:

to control a fan or damper according to temperature and humidity in a duct without a separate controller;
to implement demand-controlled ventilation in damp rooms;
to integrate the control into a BMS later via Modbus RTU.

Check before use:

the input type of the controlled device (0-10 VDC, 0-20 mA or PWM);
the supply: 18–34 VDC or 15–24 VAC ±10 %;
whether separate T and rH signals are needed – then choose a transmitter.

Important reminder: The DCTHG-2 generates one control signal from T and rH; it does not replace the power section of a fan speed controller.

FAQ

Is a separate controller required?
No, the algorithm is built in, and the output connects directly to an EC fan, AC speed controller or damper.

Can it be controlled by humidity only?
Yes, the temperature (or humidity) parameter can be switched off via Modbus RTU.

How are the settings changed?
Via Modbus RTU – the 3SModbus software with a CNVT-USB-RS485 converter, or via BMS.

How do I reset the Modbus settings?
With a jumper on PROG contacts 1 and 2 for at least 5 seconds.

What is the difference between the -F and -G versions?
-F is powered at 18–34 VDC and wired with 4 wires with separate grounds, while -G is powered at 18–34 VDC or 15–24 VAC and wired with 3 wires with a common ground.

What airflow is needed?
At least 1 m/s.

Smart duct temperature and humidity sensor-controller | -30…70°C | 0-100%rH | 0-10VDC/0-20mA/PWM | Modbus RTU | 18-34VDC/15-24VAC | IP54 | Sentera Controls | DCTHG-2

Sentera DCTHG-2 – a smart duct temperature and humidity sensor-controller: -30…+70 °C, 0–100 % rH, control output 0-10 VDC / 0-20 mA / PWM, power supply 18–34 VDC or 15–24 VAC ±10 %, IP54. Ventilation based on humidity and temperature without a separate controller.

Illustrative image may have been created using AI. The appearance of the product may differ slightly from the image shown. Please refer to the technical specification.

Attributes

Manufacturer

Sentera controls

CE certificate – a guarantee of safety, quality, and compliance

This product is marked with the CE label, which confirms that it complies with all applicable European Union directives and regulations. CE marking is not just a formality – it is an important indicator of quality and safety, ensuring that the product has been properly assessed, tested, and can be safely used throughout the EU market.

CE certification means that the product has been evaluated according to the main criteria:

Safety requirements – ensures that the product does not pose a risk to the user or the environment
Electromagnetic compatibility (EMC) – the device does not interfere with other equipment and is resistant to external disturbances
Environmental standards – complies with current ecological and material usage requirements
Operational reliability – the product is suitable for long-term use according to its intended purpose

CE marking allows this product to:

be legally supplied and used in all European Union countries
ensure a high level of quality and safety
be used in residential, commercial, and industrial environments

The CE mark is a declaration of the manufacturer’s responsibility, confirming that the product complies with all applicable standards and has been assessed according to EU legislation.

What does this mean for you as a buyer?

Safe use in everyday activities
Reliable performance and reduced risk of failure
Compliance with EU standards and requirements
Suitability for professional solutions

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Product Catalog

Smart duct temperature and humidity sensor-controller | -30…70°C | 0-100%rH | 0-10VDC/0-20mA/PWM | Modbus RTU | 18-34VDC/15-24VAC | IP54 | Sentera Controls | DCTHG-2

Smart duct temperature and humidity sensor-controller | -30…70°C | 0-100%rH | 0-10VDC/0-20mA/PWM | Modbus RTU | 18-34VDC/15-24VAC | IP54 | Sentera Controls | DCTHG-2

Operating principle

Technical specifications

Manufacturer documentation

Main functions

Where is it used?

On-demand operation

Practical application

Application guide: how it is used in practice

How to choose a duct temperature and humidity transmitter

Pros

Cons / limitations

Safety and installation notes

Quick selection guide

FAQ

Smart duct temperature and humidity sensor-controller | -30…70°C | 0-100%rH | 0-10VDC/0-20mA/PWM | Modbus RTU | 18-34VDC/15-24VAC | IP54 | Sentera Controls | DCTHG-2

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