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  • New item   -175.3€Duct CO2 sensor | CO2 0-2000ppm | T -30…70°C | 0-100%rH | NDIR | 3×0-10VDC/4-20mA/PWM | Modbus RTU | 24VAC/VDC | IP54 | Sentera Controls | DSCDG3-4
    New item   -175.3€Duct CO2 sensor | CO2 0-2000ppm | T -30…70°C | 0-100%rH | NDIR | 3×0-10VDC/4-20mA/PWM | Modbus RTU | 24VAC/VDC | IP54 | Sentera Controls | DSCDG3-4 1
    New item   -175.3€Duct CO2 sensor | CO2 0-2000ppm | T -30…70°C | 0-100%rH | NDIR | 3×0-10VDC/4-20mA/PWM | Modbus RTU | 24VAC/VDC | IP54 | Sentera Controls | DSCDG3-4 2
    New item   -175.3€Duct CO2 sensor | CO2 0-2000ppm | T -30…70°C | 0-100%rH | NDIR | 3×0-10VDC/4-20mA/PWM | Modbus RTU | 24VAC/VDC | IP54 | Sentera Controls | DSCDG3-4 3
    New item   -175.3€Duct CO2 sensor | CO2 0-2000ppm | T -30…70°C | 0-100%rH | NDIR | 3×0-10VDC/4-20mA/PWM | Modbus RTU | 24VAC/VDC | IP54 | Sentera Controls | DSCDG3-4 4
    New item   -175.3€Duct CO2 sensor | CO2 0-2000ppm | T -30…70°C | 0-100%rH | NDIR | 3×0-10VDC/4-20mA/PWM | Modbus RTU | 24VAC/VDC | IP54 | Sentera Controls | DSCDG3-4 5

    Duct CO2 sensor | CO2 0-2000ppm | T -30…70°C | 0-100%rH | NDIR | 3×0-10VDC/4-20mA/PWM | Modbus RTU | 24VAC/VDC | IP54 | Sentera Controls | DSCDG3-4

    Code: DSCDG3-4
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  • Product description

    Duct CO2 sensor | CO2 0-2000ppm | T -30…70°C | 0-100%rH | NDIR | 3×0-10VDC/4-20mA/PWM | Modbus RTU | 24VAC/VDC | IP54 | Sentera Controls | DSCDG3-4

    DSCDG3-4 – a Sentera Controls duct CO2 sensor that measures CO2 concentration (0–2000 ppm), temperature (-30…+70 °C) and relative humidity (0–100 % rH) in the duct and has three analog outputs (0-10, 2-10, 0-5 VDC, 0-20, 4-20 mA or PWM) and Modbus RTU. Supply – 24 VDC or 24 VAC ±10 %.

    Key idea:
    Three air quality indicators – three separate signals: the controller or BMS receives CO2, temperature and humidity separately and decides for itself how to control ventilation, heating or humidification. One device instead of three sensors.
    CO2 range
    0–2000 ppm
    Output
    3 × analog + Modbus RTU
    Power supply
    24 VDC or 24 VAC ±10 %
    Protection
    housing IP54, probe IP20

    Operating principle

    The device is mounted on the duct and the probe is inserted into the airflow (at least 1 m/s recommended); the 24 VDC or 24 VAC power supply and Modbus RTU are connected with Cat5 or EIB cable (wires ≥ 0.5 mm²), and the analog outputs AO1–AO3 – each with its own GND.

    An NDIR (non-dispersive infrared) CO2 sensor with ABC automatic self-calibration – for it to work, CO2 must fall to ~400 ppm (outdoor air level) at least once every 7 days – together with a temperature and humidity sensor measures the duct air. Three analog outputs are configurable – 0-10, 2-10 or 0-5 VDC (≥ 1 kΩ), 0-20 or 4-20 mA (≤ 500 Ω), PWM push-pull 12 VDC or open collector (1 kHz) – while Modbus RTU runs alongside with alarm limits for temperature, humidity, dew point difference and CO2.

    Result – the controller or BMS receives CO2, temperature and humidity both as analog signals and via digital communication, so ventilation is controlled according to the actual number of people, reducing heating / cooling losses and fan energy consumption.

    Benefits DSCDG3-4?
    Three configurable analog outputs and Modbus RTU in one – suitable for both classic controllers and BMS.

    Technical specifications

    Product type Duct CO2 sensor
    Manufacturer / code Sentera Controls / DSCDG3-4
    Measured quantities CO2, temperature, relative humidity; dew point difference (for alarms)
    CO2 range 0–2000 ppm
    Temperature range -30…+70 °C
    Humidity range 0–100 % rH, non-condensing
    Accuracy CO2 ±(30 ppm + 3 %); ±0.4 °C; ±2.5 % rH
    CO2 sensor NDIR, ABC automatic self-calibration (can be disabled via HR58)
    Outputs 3 × 0-10 / 2-10 / 0-5 VDC (≥ 1 kΩ), 0-20 / 4-20 mA (≤ 500 Ω), PWM push-pull 12 VDC or open collector (1 kHz)
    Communication Modbus RTU (RS485); firmware update via Modbus RTU
    Supply voltage 24 VDC or 24 VAC ±10 %
    Max. current (Imax) 80 mA
    Protection Supply overvoltage protection (up to 65 VDC)
    Indication Power, system, RX and TX LEDs
    Min. air velocity 1 m/s
    Housing ABS plastic, grey (RAL 7035)
    Protection class IP54 housing, IP20 probe
    Operating conditions -10…+50 °C, 10–90 % rH non-condensing; storage -10…+60 °C, 5–80 % rH
    Weight 0.13 kg (net)
    Compliance LVD 2014/35/EU, EMC 2014/30/EU, WEEE 2012/19/EU, RoHS (EU) 2015/863

    Manufacturer documentation

    ✔ Recommended by Elektrotechnikos sprendimai

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

    Main functions

    • Three configurable outputs – wide choice of signals: 0-10, 2-10, 0-5 VDC, 0-20, 4-20 mA, PWM.
    • NDIR CO2 with ABC – automatic self-calibration compensates for sensor drift.
    • Alarm limits – for temperature, humidity, dew point margin and CO2 – in Modbus registers.
    • Overvoltage protection – in the power supply circuit.
    • Modbus RTU – all measurements and settings are accessible remotely.
    • Firmware update – via Modbus RTU or SenteraWeb.
    • SenteraWeb – via a Sentera internet gateway – remote monitoring, log, notifications, mode schedules.
    • Configuration – Configuration and monitoring – the free Sentera 3SModbus software (via the CNVT-USB-RS485 converter) or the Sensistant Modbus configurator.

    Where is it used?

    • Extract air ducts in ventilation units
    • Centralised ventilation of schools, offices and halls
    • Demand-controlled ventilation (DCV) with VAV dampers
    • Heat recovery unit automation
    • BMS systems with Modbus RTU
    • Industrial automation systems with 4-20 mA inputs
    • Replacing existing duct CO2 transmitters

    On-demand operation

    For industrial automation (PLC) designers.
    4-20 mA outputs connect directly to PLC analog inputs, and the same data is available over Modbus RTU.
    For air handling unit manufacturers.
    Three configurable outputs pass CO2, temperature and humidity separately to the unit controller.
    For HVAC commissioning engineers.
    Output type, alarm limits and ABC (HR58) are set over Modbus RTU according to the site.

    Practical application

    If the PLC of an air handling unit has 4-20 mA inputs, then the DSCDG3-4 outputs are set to 4-20 mA and pass extract air CO2 (0–2000 ppm), temperature and humidity, and ABC is switched off via HR58 when necessary if CO2 does not drop to ~400 ppm within 7 days.

    Application guide: how it is used in practice

    The same DSCDG3-4 adapts to different sites – only what is connected to its outputs changes:

    Site What is connected Result Installer's note
    Central ventilation unit CO2 output → controller input (e.g. 4-20 mA) Air volume is regulated based on extract air CO2 Install in the extract duct, airflow ≥ 1 m/s
    EC fan Analog output 0-10 VDC → EC fan Speed proportional to CO2 Set the output type via Modbus
    Building with BMS Modbus RTU → A, B Measurements and alarms to the BMS Cat5 or EIB cable
    Condensation control Modbus – dew point difference alarm Warning when the dew point is approached in the duct Set the limits in HR33–HR34

    How to choose a CO2 transmitter

    Installation / output / power supply Recommended model
    Room, 3 separate outputs T / rH / CO2, 24 VDC, 4 wires RSMFF-3 (multifunction transmitter, -F)
    Room, 3 separate outputs T / rH / CO2, 24 VDC or 24 VAC, 3 wires RSMFG-3 (multifunction transmitter, -G)
    Room, 1 control output based on T / rH / CO2, 24 VDC RCMFF-3 (smart sensor, -F)
    Room, 1 control output, 24 VDC or 24 VAC RCMFG-3 (smart sensor, -G)
    Flush-mounted / surface-mounted, 1 output, powered from the 230 V mains FCMF8-R (85–264 VAC)
    Flush-mounted / surface-mounted, 1 output, 24 VDC or 24 VAC FCMFG-R (24 VAC/VDC)
    Duct, 1 control output based on T / rH / CO2, 24 VAC/VDC DCMFG-2R (smart duct sensor)
    Duct, NDIR CO2 + T + rH, Modbus RTU only DSCDG0-4 (no analog outputs)
    Duct, NDIR CO2 + T + rH, 3 analog outputs + Modbus RTU DSCDG3-4 (3 outputs) ← this model
    Rule: by installation location (wall, flush-mounting box, duct) and by what is needed: separate T / rH / CO2 signals for a controller or BMS (transmitter, 3 outputs), a single control signal directly to an EC fan or damper (smart sensor), or Modbus data only. Choose the supply according to the site's control circuit: -F – 24 VDC, 4-wire; -G – 24 VAC or 24 VDC, 3-wire; 8 – directly from the 230 V mains.
    When to choose another solution: Modbus only, without analog outputs – DSCDG0-4; for direct control with a single signal – DCMFG-2R; in a room – RSMF-3 series; without CO2 – DSTH-3 series.

    Pros

    • CO2, temperature and humidity in one device
    • Modbus RTU, firmware updated over the network
    • Wide choice of output signals, including 4-20 mA
    • NDIR CO2 with ABC self-calibration
    • IP54 housing

    Cons / limitations

    • ABC self-calibration requires the CO2 level to drop to ~400 ppm at least once every 7 days – in permanently occupied rooms it must be switched off via HR58
    • IP20 probe, an airflow of ≥ 1 m/s is required
    • It does not control the fan according to a setpoint by itself – for direct control with a single signal choose DCMFG-2R

    Safety and installation notes

    • Installation and connection are to be carried out by a qualified electrician / automation specialist with the power disconnected.
    • Supply voltage – 24 VDC or 24 VAC ±10 %.
    • Device with a common ground: never connect its common ground to other devices powered by direct voltage (DC) – the connected devices may be damaged.
    • Resetting the Modbus communication parameters – with a jumper on PROG pins 1 and 2 for at least 5 s.
    • Install in a location not exposed to direct sunlight, with the probe in the airflow.

    Quick selection guide

    CO2 0–2000 ppm
    -30…+70 °C
    0–100 % rH
    3 × 0-10 VDC / 4-20 mA / PWM
    24 VDC / 24 VAC
    IP54
    Suitable when you need:
    • to implement demand-controlled ventilation by CO2 level;
    • to pass CO2, temperature and humidity to a controller or BMS;
    • to integrate air quality data into a BMS via Modbus RTU.
    Check before use:
    • the input type of the controlled device;
    • the supply: 24 VDC or 24 VAC ±10 %;
    • whether the airflow in the duct is ≥ 1 m/s.
    Important reminder: The DSCDG3-4 measures CO2 to assess indoor air quality; it is not a gas leak or safety detector.

    FAQ

    Does it measure VOC?
    No, CO2, temperature and relative humidity are measured.
    What are the output signals?
    0-10, 2-10, 0-5 VDC, 0-20, 4-20 mA or PWM, plus 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 power supply does it operate from?
    24 VDC or 24 VAC ±10 %.
    How does ABC self-calibration work?
    The lowest CO2 value measured over 7 days is taken as the ~400 ppm baseline, so CO2 must fall to the outdoor air level at least once every 7 days.

    Duct CO2 sensor | CO2 0-2000ppm | T -30…70°C | 0-100%rH | NDIR | 3×0-10VDC/4-20mA/PWM | Modbus RTU | 24VAC/VDC | IP54 | Sentera Controls | DSCDG3-4

    Sentera DSCDG3-4 – duct CO2 sensor: CO2 0–2000 ppm, temperature -30…+70 °C, humidity 0–100 % rH, three analog outputs and Modbus RTU, 24 VDC or 24 VAC ±10 % supply. For demand-controlled ventilation.

    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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