Temperature-Humidity Transmitter
Polwax RHT300 DM
Part Code. 0397
- With Display
- Modbus RTU RS485
- Duct mounted
- Excellent linearity
- Wide sensing range
- Good long term stability
For accurate temperature and humidity monitoring in a variety of settings, the Polwax RHT is a small, high-accuracy transmitter. Its robust construction makes it suitable for industrial, pharmaceutical, and HVAC applications that need dependable environmental control. The PLX RHT is crucial for climate-sensitive settings like labs and storage facilities because it offers accurate temperature and relative humidity readings.
Polwax RHT300 DM is a duct-mounted temperature & humidity transmitter engineered for precise environmental monitoring in industrial and commercial settings.
Product Overview
The Polwax RHT300 DM series is a high-performance temperature and humidity transmitter designed for accurate environmental monitoring and reliable data delivery in demanding industrial, commercial, and HVAC applications. Built with a robust stainless-steel sensor and precision sensing technology, this series ensures real-time, high-accuracy measurement of both temperature and relative humidity, making it ideal for climate-sensitive environments such as HVAC systems, clean rooms, storage facilities, pharmaceutical areas, warehouses, and production floors.
Featuring a duct mountable design and an IP54-rated enclosure, the RHT300 DM series is engineered for long-term stability even under challenging conditions. It supports versatile output options such as 4-20 mA, RS485 with MODBUS RTU, and optional 0-10 V, allowing seamless integration with modern automation and control systems.
The series includes multiple variants tailored to different application needs:
- RHT300 DM – Standard transmitter with reliable performance across a broad range of environments.
- RHT300 DM (HT) – High-temperature variant for use where elevated temperature ranges are expected.
- RHT300 DM (HT+HA) – Advanced model combining high temperature capability with high-accuracy sensing, ideal for critical processes requiring exceptional measurement precision.
All models come with user-friendly GUI software for easy configuration and calibration, a calibration certificate, stainless-steel adaptor, and manual, ensuring smooth installation and reliable performance from day one.
Polwax RHT300 DM – Standard configuration for robust temperature and humidity sensing. Designed to integrate seamlessly with building automation, HVAC, and environmental monitoring systems, it offers dependable performance across diverse applications requiring accurate climate data.
Polwax RHT300 DM (HT) – High-Temperature variant tailored for environments with elevated temperature conditions. It extends operational range while maintaining precision humidity measurement, making it ideal for industrial zones, process chambers, and heat-intensive applications.
Polwax RHT300 DM (HT+HA) – Advanced model combining High-Temperature (HT) capability with High-Accuracy (HA) sensing. It’s perfect for critical applications that demand both extended temperature range and exceptional humidity measurement precision, such as pharmaceutical, cleanroom, and specialized manufacturing environments.
Applications

Agriculture & Greenhouses
The RHT50 WM and RHT100 WM temperature & humidity transmitters help maintain optimal climate conditions in agricultural fields and greenhouse environments. By accurately monitoring temperature and humidity levels, these devices ensure healthy plant growth, prevent crop stress, and improve yield

Pharmaceutical
In pharmaceutical environments, the RHT50 WM and RHT100 WM temperature & humidity transmitters provide precise monitoring of critical climate conditions required for drug storage and production. Accurate humidity and temperature control ensures product integrity, compliance with regulatory standards, and a stable environment for sensitive materials.

Storage & Warehouse
In storage and warehouse environments, the RHT50 WM and RHT100 WM temperature & humidity transmitters ensure accurate monitoring of climate conditions that directly affect stored goods. By maintaining optimal temperature and humidity levels, these devices help prevent spoilage, protect packaging integrity, and reduce losses.

Food & Beverage
In food and beverage environments, the RHT50 WM and RHT100 WM temperature & humidity transmitters help maintain precise climate control essential for product quality and safety. Accurate monitoring of temperature and humidity prevents spoilage, preserves freshness, and ensures compliance with industry standards throughout processing, storage, and distribution.

HVAC
In HVAC systems, the RHT50 WM and RHT100 WM temperature & humidity transmitters provide reliable monitoring of indoor climate conditions to ensure comfort, energy efficiency, and system performance. Accurate temperature and humidity data helps optimize airflow, reduce energy consumption, and maintain ideal environmental levels in commercial and residential spaces.

Clean Rooms
In clean room environments, the RHT50 WM and RHT100 WM temperature and humidity transmitters ensure precise control of critical environmental conditions. Accurate monitoring helps maintain required cleanliness standards, prevent contamination, and support compliance with regulatory norms.The RHT100 WM’s built-in display enables quick on-site verification of real-time readings.
Technical Data
| Media Compatibility | Air, non-combustible, non-corrosive gases |
| Model No |
RHT300 DM / RHT300 DM (HT) / RHT300 DM (HT+HA) |
| Part Code |
0397 3030 (RHT300 DM) / 0397 3031 (RHT300 DM) / 0397 3032 (RHT300 DM – HT) / 0397 3033 (RHT300 DM – HT+HA) |
| Measuring Range |
RHT300 DM → T: -40 to 85°C & RH: 0–100% / RHT300 DM → T: 0 to 100°C & RH: 0–100% / RHT300 DM (HT) → T: -40 to 125°C & RH: 0–100% / RHT300 DM (HT+HA) → T: -40 to 125°C & RH: 0–100% |
| Accuracy |
Standard Models → T: ±0.4°C & RH: ±1.8% / HT+HA Model → T: ±0.1°C & RH: ±0.8% |
| Display | Without Display |
| Inputs | Temperature & Humidity |
| SS Probe Length | 300 mm |
| Dimensions | 75 × 35 × 75 mm |
| Protection Class | IP54 |
| Mounting | Duct Mount |
| Language | English |
| Supply Voltage | 24V DC |
| Output | 4–20mA, RS485 MODBUS RTU / 0–10V (Optional) |
| Scope of Supply | Calibration Certificate, GUI Software, SS Adaptor, Instruction Manual |
Temperature & Humidity Transmitter – RHT300 DM Series
The Polwax RHT300 DM series duct-mount temperature and humidity transmitters are designed for precise environmental monitoring in HVAC ducts, industrial air-handling units, clean rooms, pharmaceutical facilities, and controlled process environments. These transmitters deliver reliable real-time measurement of temperature and relative humidity to ensure efficient climate control and process stability.
Model Variants
RHT300 DM – Standard Model
RHT300 DM (HT) – High Temperature
RHT300 DM (HT+HA) – High Temp + High Accuracy
Duct Mount Design
Stainless-steel probe with duct mounting for accurate air-stream measurement.
High Accuracy Sensing
Reliable and stable temperature and humidity measurement for critical applications.
High Temperature Capability
HT models support elevated temperature environments without compromising accuracy.
Industrial Output Options
Supports 4–20mA, RS485 Modbus RTU and optional 0–10V outputs.
Wide Application Use
Ideal for HVAC ducts, clean rooms, pharma, AHUs, warehouses & industrial plants.
Robust Protection
IP54-rated enclosure ensures reliable performance in industrial environments.
24V DC Supply
Designed for continuous operation with standard 24V DC power supply.


