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  • New item   -56.43€Room temperature and humidity transmitter | 0…50°C | 0-95%rH | 3×0-10VDC/0-20mA/PWM | Modbus RTU | 18-34VDC | IP30 | Sentera Controls | RSTHF-3
    New item   -56.43€Room temperature and humidity transmitter | 0…50°C | 0-95%rH | 3×0-10VDC/0-20mA/PWM | Modbus RTU | 18-34VDC | IP30 | Sentera Controls | RSTHF-3 1
    New item   -56.43€Room temperature and humidity transmitter | 0…50°C | 0-95%rH | 3×0-10VDC/0-20mA/PWM | Modbus RTU | 18-34VDC | IP30 | Sentera Controls | RSTHF-3 2
    New item   -56.43€Room temperature and humidity transmitter | 0…50°C | 0-95%rH | 3×0-10VDC/0-20mA/PWM | Modbus RTU | 18-34VDC | IP30 | Sentera Controls | RSTHF-3 3
    New item   -56.43€Room temperature and humidity transmitter | 0…50°C | 0-95%rH | 3×0-10VDC/0-20mA/PWM | Modbus RTU | 18-34VDC | IP30 | Sentera Controls | RSTHF-3 4
    New item   -56.43€Room temperature and humidity transmitter | 0…50°C | 0-95%rH | 3×0-10VDC/0-20mA/PWM | Modbus RTU | 18-34VDC | IP30 | Sentera Controls | RSTHF-3 5

    Room temperature and humidity transmitter | 0…50°C | 0-95%rH | 3×0-10VDC/0-20mA/PWM | Modbus RTU | 18-34VDC | IP30 | Sentera Controls | RSTHF-3

    Code: RSTHF-3
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  • Product description

    Room temperature and humidity transmitter | 0…50°C | 0-95%rH | 3×0-10VDC/0-20mA/PWM | Modbus RTU | 18-34VDC | IP30 | Sentera Controls | RSTHF-3

    The RSTHF-3 is a Sentera Controls room temperature and relative humidity transmitter with three analog / modulating outputs and Modbus RTU. It measures 0…+50 °C and 0–95 % rH in a room and passes the measurements to a controller, BMS or speed controller as 0-10 VDC, 0-20 mA or PWM signals. Power supply – 18–34 VDC (4-wire connection).

    Key idea:
    This is a “measuring” rather than a “deciding” device: it controls nothing itself, but delivers temperature and humidity accurately and stably as separate signals. The control logic stays in the controller or BMS, so the transmitter suits both new projects and the replacement of old sensors in existing automation.
    Measurement
    0…+50 °C / 0–95 % rH
    Outputs
    3 × 0-10 VDC / 0-20 mA / PWM + Modbus RTU
    Power supply
    18–34 VDC
    Protection
    IP30, indoors only

    Operating principle

    The transmitter is fixed to a wall (2 holes of Ø 6 mm), away from heat sources, drafts and direct sunlight. Connect the supply 18–34 VDC (VIN, GND), analog outputs AO1–AO3 (each with its own GND) and, if needed, Modbus RTU (A, /B); terminals – for wires up to 1.5 mm².

    An integrated digital sensor measures temperature and relative humidity: AO1 continuously outputs temperature, AO2 humidity, and AO3 is assigned to either temperature or humidity. The type of each output is selectable – 0-10 VDC (≥ 50 kΩ), 0-20 mA (≤ 500 Ω) or 1 kHz PWM (open collector, 3.3 or 12 VDC); all parameters are changed over Modbus RTU, which is also used to update the firmware.

    Result – the controller or BMS receives accurate (±0.4 °C, ±3 % rH) room data and uses it to control fans, humidifiers, heaters or dampers, while the light sensor and three-colour LED show on site whether the microclimate is within normal limits.

    Benefits RSTHF-3?
    One transmitter replaces two separate sensors: temperature and humidity are delivered as separate signals, with a third configurable output and Modbus RTU in addition, so the same device suits both analog and digital automation.

    Technical specifications

    Product type Room temperature and humidity transmitter
    Manufacturer / code Sentera Controls / RSTHF-3
    Series RSTHX-3 (RSTHF-3 / RSTHG-3)
    Measured quantities Temperature, relative humidity, ambient illuminance
    Temperature range 0…+50 °C
    Humidity range 0–95 % rH, non-condensing
    Accuracy ±0.4 °C (0…+50 °C); ±3 % rH (0–100 %)
    Analog outputs AO1 – temperature, AO2 – humidity, AO3 – temperature or humidity (selectable)
    Output signals 0-10 VDC (RL ≥ 50 kΩ); 0-20 mA (RL ≤ 500 Ω); PWM 1 kHz, open collector, 3.3 or 12 VDC (RL ≥ 50 kΩ)
    Communication Modbus RTU (RS485), terminals A, /B; firmware update via Modbus RTU
    Supply voltage 18–34 VDC
    Max. current (Imax) 75 mA
    Connection 4-wire, separate supply and output grounds (-F)
    Terminals For wires up to 1.5 mm²
    Indication Red / yellow / green LED, ambient light sensor
    Installation On a wall, 2 holes Ø 6 mm
    Protection class IP30 (EN 60529), indoor use only
    Weight 0.080 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

    • Three analog outputs – temperature and humidity are passed on separately, the third output is freely assignable.
    • Selectable signal type – 0-10 VDC, 0-20 mA or PWM – suitable for most controller, BMS and speed controller inputs.
    • Modbus RTU – all measurements and settings are accessible over a digital link; it can be used with Modbus only or together with the analog outputs.
    • Firmware update – over the Modbus RTU network, without removing the transmitter.
    • LED indication – red – value out of range or sensor fault, yellow – danger zone, green – normal; temperature is shown by default and can be switched to humidity.
    • Light sensor – adjustable “active” and “standby” illumination levels.
    • SenteraWeb – via a Sentera internet gateway – remote monitoring, data log, notifications and day / night modes.
    • Configuration – Configuration and monitoring – the free Sentera 3SModbus software (via the CNVT-USB-RS485 converter) or the Sensistant Modbus configurator.

    Where is it used?

    • Offices, schools, residential rooms
    • Monitoring room microclimate in a BMS
    • Ventilation and humidification control according to room humidity
    • Heating / cooling controllers with 0-10 VDC inputs
    • Archives, warehouses, server rooms where humidity matters
    • Sites with SenteraWeb remote monitoring

    On-demand operation

    For the office and school HVAC designer.
    A single room transmitter provides three analog signals and Modbus RTU, so one device is enough for the room.
    For the installer of 24 VDC automation panels.
    The -F version is wired with 4 wires with separate grounds, so the analog signal does not depend on the supply current.
    For building administrators.
    A three-colour LED on site shows whether temperature and humidity are within normal limits, without connecting to the system.

    Practical application

    If a classroom ventilation controller has two 0-10 VDC inputs and the panel has a 24 VDC supply, then the RSTHF-3 is wired with 4 wires: AO1 passes temperature 0…+50 °C, AO2 passes humidity 0–95 % rH, and the LED shows the microclimate status locally.

    Application guide: how it is used in practice

    The same RSTHF-3 adapts to different sites – only what is connected to its outputs changes:

    Site What is connected Result Installer's note
    Office, classroom AO1 (T) → heating / cooling controller, AO2 (rH) → ventilation controller One transmitter serves two control circuits Install at a height of ~1.5 m, away from radiators and windows
    Archive, warehouse AO2 (rH) → dehumidifier or fan controller Humidity is maintained within set limits, LEDs show the status locally By default the LED shows temperature – switch to humidity via Modbus
    Building with BMS Modbus RTU → A, /B All rooms are monitored centrally A separate address for each transmitter
    Remote monitoring Modbus RTU → Sentera internet gateway → SenteraWeb Data log, e-mail alerts, day / night modes A Sentera internet gateway is required
    Panel with a 24 VDC power supply VIN, GND ← 18–34 VDC; separate AO GND Separate grounds – stable analog signal on long lines Not suitable for 3-wire systems and AC power

    How to choose a room temperature and humidity transmitter

    Installation / output / power supply Recommended model
    Wall, 3 analog outputs, 18–34 VDC, 4-wire RSTHF-3 (room transmitter, -F) ← this model
    Wall, 3 analog outputs, 18–34 VDC or 15–24 VAC, 3-wire RSTHG-3 (room transmitter, -G)
    Wall, Modbus RTU only, PoM, RJ45 RSTHM-2 (room Modbus sensor)
    Wall, Modbus RTU + wall surface temperature (dew point control), PoM RWTHM-2 (with surface temperature sensor)
    Wall, direct control with 1 output, 18–34 VDC RCTHF-2 (smart room, -F)
    Wall, direct control with 1 output, 18–34 VDC or 15–24 VAC RCTHG-2 (smart room, -G)
    Wall, direct control with 1 output, 24 VDC via RJ45 (PoM) or terminals RCTHH-2 (smart room, PoM)
    Flush-mounted / surface-mounted, 1 output, powered directly from the 230 V mains FCTH8 (85–264 VAC)
    Flush-mounted / surface-mounted, 1 output, 18–34 VDC FCTHF (-F)
    Flush-mounted / surface-mounted, 1 output, 18–34 VDC or 15–24 VAC FCTHG (-G)
    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 power over the Modbus cable – RSTHM-2; for direct control of an EC fan or damper with a single signal – smart RCTH-2 series sensors; for a duct – DSTH-3 series; when CO2 is also needed – RSMF-3 / DSCDG series.

    Pros

    • Three analog outputs + Modbus RTU
    • Selectable signal 0-10 VDC / 0-20 mA / PWM
    • Accuracy ±0.4 °C, ±3 % rH
    • Firmware is updated via Modbus
    • LED indication and light sensor
    • SenteraWeb access via an internet gateway

    Cons / limitations

    • It does not control the fan according to a setting by itself – a controller or a smart DCTH / RCTH sensor is required
    • IP30 – dry rooms only
    • Humidity range 0–95 % rH non-condensing
    • The -F version is not suitable for 3-wire systems or AC supply

    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; must not be exceeded.
    • The -F version: 4-wire connection, separate supply and analog output grounds – not suitable for 3-wire systems and must never be connected to an alternating current (AC) supply.
    • Do not mix -F and -G type products on the same network.
    • For indoor use only; do not install in direct sunlight or near heat sources.

    Quick selection guide

    0…+50 °C
    0–95 % rH
    3 × 0-10 VDC / 0-20 mA / PWM
    Modbus RTU
    18–34 VDC
    IP30
    Suitable when you need:
    • to measure temperature and humidity in a room and pass them to a controller as separate signals;
    • to integrate measurements into a BMS via Modbus RTU;
    • to replace old separate temperature and humidity sensors with a single device.
    Check before use:
    • the controller input type (0-10 VDC, 0-20 mA or PWM);
    • the supply voltage and the number of wires (-F – 4-wire DC, -G – 3-wire AC/DC);
    • whether the installation location reflects the real indoor microclimate.
    Important reminder: The RSTHF-3 is a measuring transmitter: it transmits data but does not control the fan according to a setting by itself.

    FAQ

    Which signals can be obtained?
    Each of the three outputs – 0-10 VDC, 0-20 mA or 1 kHz PWM, plus Modbus RTU.
    What is AO3 for?
    It can be assigned to temperature or humidity, for example for a second controller or indicator.
    How does it differ from RSTHG-3?
    The -F version 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.
    Can it be connected via Modbus only?
    Yes, analog outputs do not have to be used, and if power over the Modbus cable is needed – choose the RSTHM-2.
    How do I reset the Modbus settings?
    With a jumper on PROG contacts 1 and 2 for at least 5 seconds.
    Is it suitable for damp rooms?
    No, the IP30 enclosure is for dry rooms, and humidity is measured up to 95 % rH without condensation.

    Room temperature and humidity transmitter | 0…50°C | 0-95%rH | 3×0-10VDC/0-20mA/PWM | Modbus RTU | 18-34VDC | IP30 | Sentera Controls | RSTHF-3

    Sentera RSTHF-3 – room temperature and humidity transmitter: 0…+50 °C, 0–95 % rH, three 0-10 VDC / 0-20 mA / PWM outputs and Modbus RTU, 18–34 VDC supply. Suitable for ventilation, humidification and BMS automation.

    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.

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