Intrinsically Safe Humidity and Temperature Transmitters

The Vaisala HMT370EX series provides precise, dependable humidity and temperature measurements in hazardous environments, including Zone 0 classifications, by combining an intrinsically safe transmitter with Vaisala's HUMICAP® sensor technology. The complete transmitter can be mounted directly in the hazardous zone and withstands continuous exposure to combustible gases or dust without the need for extra protective enclosures. It was designed as the replacement for the well-known HMT360 series. Its detachable probe module allows probes to be changed or taken out for calibration outside of the dangerous region, and the transmitter automatically restores settings, requiring little reconfiguring. For more sophisticated configuration and monitoring, Vaisala Insight PC software can be used in addition to the local display for output configuration and calibration.

Key specifications and features:

• Intrinsically safe (Ex i), certified for operation up to Zone 0/20 (ATEX, IECEx, FM, UKEX, CML, NEPSI, KCs)
• Vaisala HUMICAP® R2 sensor for humidity, with excellent long-term stability and negligible hysteresis
• Relative humidity range of 0–100 %RH, accuracy ±0.8 %RH (0–90 %RH) at +23 °C
• Temperature range of −70 … +180 °C (−94 … +356 °F) depending on probe option, accuracy ±0.1 °C (±0.18 °F) via Pt1000 RTD sensor
• Six interchangeable probe options: HMP371 (wall mount), HMP373 (confined spaces), HMP374 (pressurized spaces), HMP375 (high temperature), HMP377 (high humidity), and HMP378 (pressurized pipelines)
• Outputs an extensive range of calculated parameters beyond RH and temperature, including dew point, absolute humidity, mixing ratio, wet-bulb temperature, water concentration, and enthalpy
• Graphical LCD display or non-display model available
• Traceable calibration certificate included
• Compatible with Vaisala Insight PC software and the Indigo80 handheld indicator