Economy Humidity and Temperature Transmitter with RS485 Output HG803
HENGKO HG803 SERIES
Industrial Temperature and Humidity Transmitter
Reliable temperature and relative humidity monitoring for HVAC, air ducts, warehouses, industrial processes and equipment integration.
The HENGKO HG803 Series is a flexible industrial temperature and humidity transmitter platform designed around different sensing positions, installation methods and control-system requirements. Select from remote, replaceable, integrated and air-duct probe configurations.
| Measurement | Temperature + Relative Humidity |
| Humidity Range | 0–100% RH |
| Digital Output | RS485 Modbus-RTU |
| Analog Output | 4–20 mA / 0–5 V / 0–10 V |
| Configurations | Split / Replaceable / Integrated / Air Duct |
WHY HG803
One Transmitter Platform. Multiple Sensing Configurations.
Industrial temperature and humidity monitoring rarely uses one installation method. HG803 is designed as a flexible transmitter platform that can be configured for remote sensing, replaceable probes, integrated installation or direct air-duct measurement.
Flexible Probe Options
Choose split, replaceable, integrated or air-duct probe configurations according to sensing position, installation space and maintenance requirements.
Industrial Signal Outputs
RS485 Modbus-RTU is available for digital system integration, with 4–20 mA, 0–5 V and 0–10 V analog output configurations.
Remote Measurement
Remote probe configurations allow the sensing element to be positioned away from the transmitter, with cable lengths available up to approximately 20 meters.
Industrial Reliability
Industrial-grade ESD protection, reverse-power protection and multiple probe structures support reliable operation in demanding monitoring environments.
HG803 CONFIGURATIONS
Four Probe Configurations for Different Installations
Choose the probe structure according to sensing position, maintenance requirements and installation method.
PROBE OPTIONS
Multiple Probe Designs for Different Installation Conditions
HG803 supports multiple sensing probe structures, allowing the sensing element to be positioned where temperature and humidity actually need to be measured.
✓ Standard Probe — general industrial environmental monitoring
✓ Flanged Long Probe — deep insertion into ducts or process equipment
✓ Flanged Short Probe — fixed duct or chamber installation
✓ Threaded Probe — threaded process connection
✓ Plastic Housing Probe — general-purpose environmental sensing
✓ Replaceable Probe — maintenance-friendly applications
TECHNICAL DATA
HG803 Technical Specifications
Actual specifications depend on probe type and selected configuration. The table below summarizes the main capabilities of the HG803 platform.
| Measured Parameters | Temperature and Relative Humidity |
| Temperature Range | Split stainless-steel probe configurations: approximately −40 to +120°C. Plastic remote / replaceable probe configurations: approximately −40 to +100°C. Air-duct configurations: approximately −40 to +80°C. Integrated plastic sensor housing: approximately −20 to +60°C. |
| Humidity Range | 0–100% RH |
| Temperature Accuracy | ±0.3°C @ 25°C typical; higher-accuracy configurations available |
| Humidity Accuracy | ±3% RH typical @ 60% RH, 25°C; higher-accuracy options available |
| Temperature Long-Term Stability | ≤0.1°C/year |
| Humidity Long-Term Stability | ≤1% RH/year |
| Digital Output | RS485 Modbus-RTU |
| Analog Output Options | 4–20 mA / 0–5 V / 0–10 V |
| Baud Rate | 1200 / 2400 / 4800 / 9600 / 19200 / 115200 bps; default 9600 bps |
| Supply Voltage | 10–30 VDC |
| Transmitter Operating Environment | Approximately −20 to +60°C, 0–95% RH, non-condensing |
| Probe Cable | Remote cable configurations available up to approximately 20 m |
| Protection Features | Industrial-grade ESD protection and reverse-power protection |
| Protocol / Reading | Supports single-register and multiple-register reading |
| Temperature Unit | °C standard; °F customization available |
SYSTEM INTEGRATION
Connect Directly to Industrial Control Systems
HG803 is designed for both standalone environmental monitoring and integration into automated industrial systems.
✓PLC
✓Industrial control host
✓Building Management System (BMS)
✓Data acquisition system
✓Digital display meter
✓Environmental monitoring platform
Available Signal Configurations
| RS485 | Modbus-RTU digital communication |
| 4–20 mA | Temperature + humidity analog output |
| 0–5 V | Voltage output configuration |
| 0–10 V | Voltage output configuration |
| Hybrid | Analog output + RS485 configurations available |
APPLICATIONS
Built for Industrial Temperature & Humidity Monitoring
From warehouses to air ducts, HG803 can be configured around the actual installation environment rather than forcing one sensor structure to fit every application.
HVAC & Air Ducts
Monitor supply air, return air and environmental conditions inside HVAC ducts and ventilation systems.
Warehouses & Storage
Continuous temperature and humidity monitoring for warehouses, storage rooms and distribution facilities.
Grain & Agriculture
Environmental monitoring for grain storage, greenhouses and agricultural facilities.
Clean Rooms & Laboratories
Monitor controlled environments where temperature and humidity stability are important to processes and product quality.
Industrial Processes
Suitable for process equipment, industrial rooms, air handling systems and environmental monitoring networks.
Rail & Infrastructure
Remote environmental monitoring for tunnels, rail systems, equipment rooms and infrastructure applications.
Communication Rooms
Monitor temperature and humidity around servers, communication equipment and electrical infrastructure.
Pharmaceutical Facilities
Environmental sensing for pharmaceutical production, storage and controlled processing areas.
OEM Equipment
Flexible probe structures and industrial outputs make HG803 suitable for integration into OEM equipment and monitoring systems.
MODEL SELECTION
Which HG803 Configuration Should You Choose?
| Installation Requirement | Recommended Configuration |
|---|---|
| General room / warehouse monitoring | HG803 Integrated Probe |
| Sensor must be installed away from transmitter | HG803 Split Probe |
| Sensor requires frequent replacement or maintenance | HG803 Replaceable Probe |
| HVAC duct / ventilation system | HG803 Air Duct Type |
| Deep insertion into duct or chamber | Flanged Long Probe |
| Fixed threaded process connection | Threaded Probe |
| PLC / BMS digital communication | RS485 Modbus-RTU |
| Traditional industrial analog input | 4–20 mA |
OEM & CUSTOMIZATION
Need a Different Probe Length, Connection or Output?
HG803 can be configured around your equipment and installation environment. HENGKO supports industrial customers, system integrators and equipment manufacturers with customized sensing solutions.
✓Custom probe length
✓Remote probe cable length
✓Threaded process connections
✓Flange mounting
✓Replaceable probe design
✓RS485 Modbus-RTU
✓4–20 mA / voltage outputs
✓Temperature unit customization
✓OEM equipment integration
FAQ
HG803 Temperature & Humidity Transmitter FAQ
Does HG803 support RS485 Modbus?
Yes. HG803 supports RS485 communication using the Modbus-RTU protocol, making it suitable for PLC, BMS and industrial monitoring systems.
Can HG803 provide a 4–20 mA output?
Yes. Depending on configuration, HG803 can provide 4–20 mA, 0–5 V or 0–10 V analog outputs in addition to RS485 communication.
Can the temperature and humidity probe be replaced?
Yes. The HG803 Series includes a detachable and replaceable probe configuration. The sensing head can be replaced independently, helping reduce maintenance cost and downtime.
Can HG803 be installed inside an HVAC duct?
Yes. The HG803 Air Duct configuration is designed for duct and pipeline monitoring. Threaded, flange and extended probe installation options are available.
How long can the remote probe cable be?
Selected split-probe configurations can support remote sensor cables up to approximately 20 meters. Final cable length should be confirmed according to the selected probe and signal configuration.
What temperature range does HG803 support?
The temperature range depends on the selected sensing probe. Split stainless-steel probe configurations can reach approximately −40 to +120°C, while integrated, replaceable and air-duct configurations have different operating ranges.
Which HG803 probe should I choose?
The correct probe depends on your installation method, operating temperature, humidity range, required insertion depth, process connection and maintenance requirements. Send HENGKO your application conditions and we can recommend the appropriate configuration.
NEED HELP SELECTING A SENSOR?
Tell Us Your Temperature & Humidity Monitoring Requirements
Send us your temperature range, humidity range, installation method, probe length, process connection, cable length and required output signal. Our engineers will recommend the appropriate HG803 configuration.
Please provide:
✓ Temperature range
✓ Humidity range
✓ Installation environment
✓ Probe / insertion length
✓ Thread or flange connection
✓ Cable length
✓ RS485 / 4–20 mA / voltage output
Can't find a product that meets your needs? Contact our sales staff for OEM/ODM customization services!
