NOVOS 3 (EPD) RS485 Modbus
Room sensor, optional with CO2 | VOC | Temperature | Humidity
Datasheet
Subject to technical alteration
Issue date: 18.06.2025
NOVOS
Modbus
Illustration of the NOVOS sensor units.
Application
The maintenance-free sensor creates conditions for a pleasant indoor climate and well-being. Typical applications include schools, office buildings, hotels, cinemas, and similar environments. The device is available with an optional LED display featuring a color-changing traffic light function to indicate measured values. Threshold values can be individually configured using the Thermokon NOVOSapp.
Types Available
- Room sensor - active RS485 Modbus
- NOVOS 3 Temp RS485 Modbus*²
- NOVOS 3 Temp_rH RS485 Modbus*²
- NOVOS 3 CO2 Temp RS485 Modbus*¹,²
- NOVOS 3 CO2 Temp_rH RS485 Modbus*¹,²
- NOVOS 3 VOC Temp RS485 Modbus*²
- NOVOS 3 VOC Temp_rH RS485 Modbus*²
- NOVOS 3 CO2 + VOC Temp RS485 Modbus*¹,²
- NOVOS 3 CO2 + VOC RS485 Modbus*¹,²
- NOVOS 3 CO2 + VOC Temp_rH RS485 Modbus*¹,²
*¹ optional available with TLF (RGB-LED to display the air quality)
*² optional available with ePaper display
Security Advice – Caution
!
The installation and assembly of electrical equipment should only be performed by authorized personnel.
The product should only be used for its intended application. Unauthorized modifications are prohibited! The product must not be used in conjunction with any equipment that, in case of failure, may threaten, directly or indirectly, human health or life, or result in danger to human beings, animals, or assets. Ensure all power is disconnected before installation. Do not connect to live/operating equipment.
Please comply with:
- Local laws, health & safety regulations, technical standards and regulations
- Condition of the device at the time of installation, to ensure safe installation
- This data sheet and installation manual
Build-up of Self-Heating by Electrical Dissipative Power
Sensors with electronic components generate dissipative power, affecting the ambient air temperature measurement. This power increases linearly with rising operating voltage. This effect must be considered when measuring temperature. For a fixed operating voltage (±0.2 V), this is typically compensated by adding or subtracting a constant offset value. Thermokon transducers can operate with variable voltages. They are factory set to a reference operating voltage of 24 V. At this voltage, the measurement error of the output signal is minimized. Other operating voltages may cause measurement deviations due to changes in the sensor electronics' power loss.
Recalibration can be performed directly on the unit or via a software variable (app or bus). Remark: Draughts can improve the dissipation of power at the sensor, potentially causing temporary fluctuations in temperature measurements.
Application Notice for Humidity Sensors
Under normal environmental conditions, it is recommended to calibrate the sensor annually to verify compliance with the required accuracy. The following conditions can damage the sensor element or lead to a long-term loss of specified accuracy:
- Mechanical stress
- Contamination (e.g., dust, fingerprints)
- Aggressive chemicals
- Ambient conditions (e.g., condensation on the measuring element)
! Do not touch the sensor elements!
Re-calibration or exchange of the sensor element is not covered by the general warranty.
Information About Self-Calibration Feature CO2
All gas sensors are subject to drift. The extent of drift depends on component usage and product design. Environmental conditions such as mechanical stress (including temperature fluctuations), contamination (dust, fingerprints), abrasive chemicals, and high humidity or condensation on the measuring element can accelerate sensor aging and wear. An internal self-calibration function with dual-channel technology compensates for this drift. Thermokon sensors are designed for permanent use, such as in hospitals.
Information About Indoor Air Quality CO2
EN 13779 defines several classes for indoor air quality:
| Category | CO2 content above outdoor air (ppm) | Typical range | Description |
|---|---|---|---|
| IDA1 | < 400 ppm | 350 ppm | Standard value |
| IDA2 | 400..600 ppm | 500 ppm | Good indoor air quality |
| IDA3 | 600..1,000 ppm | 800 ppm | Standard indoor air quality |
| IDA4 | > 1,000 ppm | 1,200 ppm | Poor indoor air quality |
Application Notice for Air Quality Sensors VOC
Volatile organic compounds (VOCs) are gaseous and vaporous organic substances in the air. VOC sensors monitor a significant portion of humanly perceived air quality, including odors from body odor, tobacco smoke, materials, furniture, carpets, paints, and adhesives. The VOC value is an application-specific indicator of air quality and does not provide information about individual VOC components. A VOC sensor works by oxidizing organic molecules, which changes the resistance of the semiconductor. Contact with the sensitive sensors must be avoided as it will invalidate the warranty. The VOC sensor is factory calibrated and can be recalibrated using the NOVOSapp if necessary.
Technical Data
| Parameter | Value |
|---|---|
| Measuring values | Temperature | Humidity | CO2 | VOC |
| Network technology | RS485 Modbus, RTU, half-duplex, baud rate 9.600, 19.200, 38.400 or 57600, parity: none (1 stopbit, alternative 2 stopbits), even or odd (1 stopbit), Fail-safe Biasing required |
| Power supply | 15..35 V = (or 19..29 V ~)* SELV |
| Power consumption | typ. 0.4 W (24 V =) | 0.8 VA (24 V ~) |
| Inputs | 1x input for floating contact |
| Display (optional) | ePaper, as measured value display, display can be parameterized via Thermokon NOVOSapp |
| Enclosure | PC VO, pure white, design cover (optional) |
| Protection | IP20 according to DIN EN 60529 |
| Cable entry | rear entry, breaking points bottom, drill mark top |
| Connection electrical | tool-free mountable spring terminal, max. 1.5 mm² |
| Ambient condition | -20..+70 °C, max. 85% non-condensing, with CO2 or VOC sensor operating temperature range 0..+50 °C |
| Mounting | Surface mounted on flush-mounting box (Ø=60 mm) or to be mounted flat onto the surface using screws, base part can be mounted and wired separately |
| Notes | For configuration, an optional programming dongle (Bluetooth) is available (refer to accessories) |
Temperature
| Measuring range temp | -20..+70 °C |
| Accuracy temperature | ±0.5 K (typ. at 21 °C) |
Humidity (optional)
| Measuring range humidity (optional configurable) | relative humidity: 0..100 % rH absolute humidity: 0..50 | 0..80 g/m³ Enthalpy: 0..85 KJ/kg dew point: 0..+50 | -20..+80 °C |
| Accuracy humidity | configurable via Thermokon NOVOSapp or BUS ±2% between 10..90% rH (typ. at 21 °C) |
CO2 (optional)
| Measuring range CO2 | 0..2000 ppm | 0..5000 ppm (configurable via Thermokon NOVOSapp or BUS) |
| Accuracy CO2 | ±50 ppm +3% of reading (typ. at 21 °C, 50% rH, 1015 hPa) |
| Calibration | self-calibration dual channel |
| Sensor | NDIR (non-dispersive, infrared) |
| Display (optional) | RGB-LED indicating air quality (traffic light function 'TLF') |
VOC (optional)
| Measuring range VOC | 0..100 % |
| Sensor | VOC sensor (heated metal oxide semiconductor) |
*Power supply: When multiple BUS devices are supplied by a single 24 V AC voltage supply, ensure that all positive (+) operating voltage input terminals of the field devices are connected together, and all negative (-) operating voltage input terminals (=reference potential) are connected together (in-phase connection). Reversed polarity at one field device can cause a supply voltage short circuit. The resulting short-circuit current can damage the device. Therefore, ensure correct wiring.
Mounting Advices
The accuracy of the room sensors is influenced by technical specifications and the installation type. During assembly:
- Seal the mounting box (if present).
- Installation type, air draught, heat sources, radiation heat, or direct sunlight can affect the measurement.
- Building material specific properties of the installation location (brick, concrete, partition wall, cavity wall, etc.) can affect the measurement.
Assembly is not recommended in locations with:
- Air draught (e.g., near windows/doors/fans)
- Heat sources
- Direct sunlight
- Niches / between furniture
Please ensure the device is de-energized before installation.
Installation can be performed on a flat wall surface or a flush-mounted box. Select a representative location, avoiding direct sunlight and draughts, which could falsify measurement results. Seal the end of any installation tubes.
- For wiring, remove the upper part of the device from the base plate. The base plate and upper part are detachably connected via locking lugs.
- Mount the base plate to the flat wall surface using rawlplugs and screws.
- Attach the device to the base plate and secure it with a screw.
Housing Open / Close
Snap the upper part of the housing into the locking lug on the upper side.
Illustration showing how to snap the upper part of the housing into the locking lug.
Fix the upper part of the housing on the underside with the screw provided.
Illustration showing how to fix the upper part of the housing with a screw.
Cable Entry
There are predetermined breaking points for two optional cable entries on the underside of the base plate.
Illustration of cable entry points on the base plate.
On the upper side of the base plate, there are two grits for positioning a drill hole (max. Ø 6 mm).
Illustration showing grits for drill hole positioning.
! When using a drill, ensure the base plate is firmly clamped. Reduce pressure and drill carefully to avoid sudden breakthrough.
Connection Plan
Room sensor - active RS485 Modbus
NOVOS 3 RS485 Modbus
| Terminal | Signal | Description |
|---|---|---|
| 1 | UB+ | 15..35 V / 19..29 V ~ A |
| 2 | GND- | 0V |
| 3 | A+ | BUS A |
| 4 | A+ | BUS A |
| 5 | B- | BUS B |
| 6 | B- | BUS B |
| 7 | DI | digital input (for floating contact → GND) |
With alternating voltage, ensure correct polarity. Please refer to the technical data.
Don't forget the BUS termination (120 Ω) at the last device of the line! (Not included in delivery)
Configuration
Configuration is performed in a powered state. The following options are available for configuring the device:
| Device connection | Configuration adapter | Layout | Configuration software |
|---|---|---|---|
| RS485 | USB-RS485 Converter | PC/Notebook |
Parameterization via desktop PC/Notebook with uConfig software and a USB/RS485 converter (Item No. 668293) |
| Thermokon USB-Interface | PC/Notebook |
Parameterization via desktop PC/Notebook with uConfig software, via Thermokon USB-Interface* (Item No. 597838) | |
| Micro-USB | USB-Bluetooth Dongle | Smartphone/Tablet |
Parameterization with mobile devices via Bluetooth and NOVOSapp. A separately available Bluetooth dongle* is required (item no. 668262). GET IT ON Google Play Download on the App Store |
*Commercially available Bluetooth dongles or USB to Micro-USB adapter cables are not compatible. A mobile device must support at least Bluetooth version 4.1. The configuration app and instructions can be downloaded from the Google Play Store or the Apple App Store.
A configuration during operation is additionally possible via BMS through RS485 connection.
Illustration showing the position of the micro USB port for configuration.
Display
The display scales automatically based on the device and the number of measured variables. Parameters like display/hiding of measured variables are changed via the app. Software and hardware versions are displayed during the boot process.
Examples of different display configurations showing measured values.
Symbols
Header symbols (can be displayed in the header via bus)*:
Temperature |
RH Humidity |
Eco-Mode |
Notice |
Window contact |
Occupied |
Unoccupied |
Heating |
Cooling |
Maintenance |
VOC |
VOC |
CO2 |
CO2 |
Additional symbols (displayed when triggered):
- Traffic light function*: Threshold value Colored LED illumination
- Notice: Internal sensor error (display next to measured variable)
- LED Illumination: Measured value range
*depending on variant
TLF - Traffic Light Function (Optional)
The traffic light function can be implemented with any available measured variable. Different colors can be assigned for up to 5 different measuring ranges.
Example: CO2 TLF
The LED visualizes the air quality value (Thresholds optionally configurable via Thermocon NOVOSapp).
| CO2 (factory default) | Behavior of the LED |
|---|---|
| 0..750 ppm | LED lights up in green |
| 751..1250 ppm | LED lights up in yellow |
| 1251..2000 ppm | LED lights up in red |
DIP-Switch-Settings
The Modbus address of the device is set in the range of 1-63 (binary encoded) using a 6-pole DIP switch. With address 0 via DIP, an extended address range (64-247) is available via NOVOSapp.
Modbus-Adress - DIP 1..6 (binary coded)
Value: 2⁰ (1) | 2¹ (2) | 2² (4) | 2³ (8) | 2⁴ (16) | 2⁵ (32)
Factory default, address 63
Illustration of DIP switch settings for Modbus address.
Baud rate - DIP 7 & 8
| DIP 7 | DIP 8 | Baud rate |
|---|---|---|
| off | off | 9600 |
| on | off | 19200 |
| off | on | 38400 |
| on | on | 57600 (factory default) |
Illustration of DIP switch settings for baud rate.
Parity / Stop bits - DIP 9 & 10
| DIP 9 | DIP 10 | Parity |
|---|---|---|
| off | off | None - 2-Stopbits |
| on | off | Even - 1 Stopbit |
| off | on | Odd - 1 Stopbit |
| on | on | None - 1-Stopbit (factory default) |
Illustration of DIP switch settings for parity and stop bits.
Modbus Registers
| Address | Access | Description | Scaling / Unit |
|---|---|---|---|
| 501 | R | relative humidity | 850 = 85,0 %rF | 0.1 %rF |
| 505 | R | CO2 | 1.0 ppm |
| 506 | R | VOC | 1.0 % |
| 507 | R | CO2/VOC MIX | 1.0 |
| 514 | R | Status digital input | open = 0 closed = 1 |
Register 1100 = 1 (Unit SI)
| Address | Access | Description | Scaling / Unit |
|---|---|---|---|
| 500 | R | Temperature | 210 = 21,0 °C | 0.1 °C |
| 502 | R | Absolute humidity | 1500 = 15,0 g/m³ | 0.1 g/m³ |
| 503 | R | Enthalpy | 550 = 55,0 kJ/kg | 0.1 kJ/kg |
| 504 | R | Dew point | 180 = 18,0 °C | 0.1 °C |
Register 1100 = 2 (Unit Imperial)
| Address | Access | Description | Scaling / Unit |
|---|---|---|---|
| 500 | R | Temperature | 700 = 70,0 °F | 0.1 °F |
| 502 | R | Absolute humidity | 4200 = 4,2 gr/ft³ | 0.1 gr/ft³ |
| 503 | R | Enthalpy | 240 = 24,0 BTU/lb | 0.1 BTU/lb |
| 504 | R | Dew point | 600 = 60,0 °F | 0.1 °F |
Modbus addresses:
NOVOS-RS485 Modbus Interface
A detailed description of the Modbus addresses can be found at: https://www.thermokon.de/direct/files/novos-rs485-modbus-manual.zip
Product Testing and Certification
Declaration of conformity
The declaration of conformity for the products can be found on our website: https://www.thermokon.de/direct/en-gb/categories/novos-3
CE
Notes on Disposal
The crossed-out wheelie bin symbol indicates that the product or removable batteries must not be disposed of with household or commercial waste. Within the EU, you are legally obliged to dispose of the product separately and appropriately in accordance with national laws. Alternatively, please contact your supplier or Thermokon Sensortechnik GmbH. Further information can be found at: www.thermokon.com
Dimensions (MM)
Diagram showing the dimensions of the NOVOS 3 sensor.
109 mm (height)
100.5 mm (width)
43 mm (depth)
23 mm (depth)
60 mm (diameter for flush-mounting box)
56 mm (width)
Accessories (Optional)
- Rawlplugs and screws (2 pcs. each) - Item No. 102209
- PSU-UP24 - flush mount power supply 24 V (AC Input: 100..240 V ~ | DC Output 24 V = 0.5 A) - Item No. 645737
- Mounting bracket (surface mounted) white - Item No. 795050
- Mounting bracket (surface mounted) black - Item No. 795074
- Bluetooth dongle - Item No. 668262
- Thermokon USB-Interface - Item No. 597838
- USB RS485 Modbus RTU Logger - Item No. 809917
- USB Interface RS485 (incl. driver CD) - Item No. 668293
- RS485 Biasing Adapter - Item No. 811378
