1 Introduction to HMT370EX Series
Vaisala HUMICAP® Humidity and Temperature Transmitter Series HMT370EX is the ideal
solution for measuring humidity in hazardous areas. Intrinsically safe and robust, HMT370EX
operates safely and reliably even in the most hazardous areas, such as Zone 0. The next-
generation HMT370EX transmitter can be used as a replacement for the long-running HMT360
transmitter series in all HMT360 applications.
HMT370EX can be installed directly in explosive areas. It can withstand continuous exposure to
potentially explosive environments that contain flammable gases or dust, and requires no
additional protective enclosures for operation in either gas or dust environments.
HMT370EX offers several probe options for different applications. Thanks to the detachable
probe module, probes can be easily replaced and removed for calibration outside the
hazardous area without removing the entire transmitter.
The transmitter has 2 analog current output channels (4 ... 20 mA) for connection via safety
barriers. For easy-to-use access to configuration, diagnostics, and calibration and adjustment
functionalities, the probe and transmitter body can be connected to Vaisala Insight PC
software for configuration either together as one unit or separately.
1.1 Basic features and options
• Available measurement parameters: relative humidity (RH) and temperature (T)
• Calculated measurement parameters include
temperature, absolute humidity, mixing ratio, water concentration, water mass
fraction, water vapor pressure, enthalpy, and oil/fuel moisture with special models
• Ex classification: IECEx and ATEX certified for use in Zone 0 and Zone 20 environments:
for full Ex classifications, see
• 2 analog outputs (4 ... 20 mA, scalable, isolated)
• Display options: graphical LCD display or non-display model
• Power supply input: 12 ... 28 V
• Compatible with Vaisala Insight PC software
1.2 More information
For further information on using, configuring, and maintaining the transmitter after
installation, see HMT370EX User Guide (available at www.vaisala.com/HMT370EX).
1)
Additional calculated parameters available: see product information at
Chapter – Introduction to HMT370EX Series
1)
: dew point temperature, wetbulb
Table 1 (page
6).
vaisala.com
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