The HTX2 and HTX3 High Accuracy Humidity/Temperature Transmitters from Greystone Energy Systems are dedicated humidity/temperature transmitters. They target environments that require tight control and long‑term stability. Both models use a thermoset polymer humidity sensor for reliable RH measurement. Key performance figures include ±1% RH accuracy and temperature accuracy to ±0.1–0.15°C depending on model.
Modern buildings rely on accurate environmental data. Without it, control systems guess rather than respond. That often leads to waste, discomfort, and unstable indoor conditions. Humidity and temperature transmitters solve this problem. They measure room or duct conditions and send clear signals to controllers.
Although they share a common purpose, each model suits different project needs. The HTX2 focuses on dependable sensing with practical outputs. Meanwhile, the HTX3 adds advanced options and wider integration flexibility. Together, they show how modern sensing supports smarter buildings.
Humidity and Temperature sensing
Greystone fits a thermoset polymer‑based humidity sensor in both units. This sensor provides linearised output and good long‑term stability. Consequently, the devices suit spaces where drift must be minimised.
Temperature sensing: HTX2 versus HTX3
The HTX2 uses a bipolar transistor sensor chip for temperature. Therefore, it achieves tighter temperature accuracy and supports additional derived variables such as dew point, enthalpy and wet‑bulb temperature.
By contrast, the HTX3 employs a Class A RTD for temperature sensing. This choice gives robust performance and simplifies the measurement set to RH and dry‑bulb temperature. Both approaches are industry standard and suit different installation priorities.
Outputs and communications
Both transmitters provide dual analog outputs and support digital protocols. Specifically, BACnet and Modbus are available for networked building management systems. This flexibility allows integrators to use the devices with legacy controllers or modern BMS platforms.
Mechanical protection and probe design
Greystone encloses the electronics in a weatherproof polycarbonate housing with a hinged, gasketed cover. The sensing elements sit inside a stainless‑steel probe fitted with a 20‑micron PTFE filter. As a result, the units resist dust and moisture while remaining serviceable.
Typical applications in HVAC and BMS
These transmitters are suited to data centres, healthcare, pharmaceutical and horticulture environments. For example, data centres need tight humidity control to avoid electrostatic issues. Similarly, pharmaceutical cleanrooms require traceable, stable readings for compliance. The HTX series meets these needs through accuracy and protocol support.
Installation and configuration
Installers mount the units in wall or duct locations depending on the model variant. Then they select outputs and variables in the field. Moreover, an optional NIST‑traceable calibration certificate is available for projects that demand documented accuracy.
Practical considerations and selection guidance
When choosing between HTX2 and HTX3, consider the following:
- Accuracy needs: choose HTX2 for the tightest temperature tolerance.
- Variable set: choose HTX2 if you require dew point or enthalpy outputs.
- Simplicity and robustness: choose HTX3 for a streamlined RH/temperature pair.
Finally, ensure your BMS supports BACnet or Modbus if you plan to use digital communications. If not, the dual analog outputs provide a reliable fallback.
The HTX2 and HTX3 offer high accuracy, flexible outputs and rugged packaging for demanding HVAC and building management tasks. They balance precision with practical installation features. Therefore, they represent a strong option where environmental control and data integrity matter.
Automated Control Solutions (ACS) is an importer and distributor of Building Management Systems , Energy Efficient Building Automation Controllers and the relevant field devices for sensing and control of heating, ventilation and air-conditioning (HVAC) systems. Through our strong system integrator (SI’s) channel, we have a network of installers throughout South Africa, as well as Namibia & Kenya, who have been trained to supply, install and engineer, Tridium Building Management Systems and the related controllers and field devices.
We understand that our customers want the latest technologies, which is why we have partnered with innovative, dynamic companies like Greystone Energy Systems to enable us to offer our clients best in class equipment for their HVAC projects. Contact us to see how we can help.
