Top-of-the-line model for demanding industrial applications. A large numerical and graphical display. A fully configurable transmitter. Optional data logging and (W)LAN interface.

Six models for demanding applications: HMT331 for wall mounting HMT333 for duct mounting and tight spaces HMT334 for high pressures up to 100 bar and vacuum conditions HMT335 for high temperatures HMT337 for high humidity and meteorological applications HMT338 for pressurized pipelines up to 40 bar Warmed probe for superior performance in condensing environments Shows measurement trends and history graphically Corrosion resistant IP65 housing NIST traceable (certificate included) Optional integrated data logging, with over four years of measured history LAN and WLAN communication options

Relative humidity measurement
	Measurement range Accuracy at +20 °C (68 °F) Sensor	0 ... 100 % RH ± 1.0 % RH (0 ... 90 % RH) ± 1.7 % RH (90 ... 100 % RH) Vaisala HUMICAP® 180 Vaisala HUMICAP® 180R
Temperature measurement
	Measurement range      HMT331      HMT333      HMT334/335/337/338 Accuracy at +20 °C (68 °F) Sensor	-40 ... +60 °C (-40 ... +140 °F) -40 ... +80 °C or  -40 ... +120 °C (-40 ... +176 °F or -40 ... +248 °F) -70 ... +180 °C (-94 ... +356 °F) ± 0.2 °C PT100 RTD 1/3 Class B IEC 751
Other variables available (depends on model)
	Dewpoint, temperature, mixing ratio, absolute humidity, wet bulb temperature, enthalpy, water vapor pressure.
Operating environment
	Temperature      for probe      for transmitter body      with display Pressure      HMT334      HMT338      HMT333/335/337	same as measurement ranges -40 ...+ 60 °C (-40 ... +140 °F) 0 ...+ 60 °C (+32 ... +140 °F) 0 ... 10 MPa (0 ... 100 bar) 0 ... 4 MPa (0 ... 40 bar) vapor tight
Inputs and outputs
	Operating voltage      with optional power supply module Power consumption @ 20 °C (Uin24 VDC)      RS-232      Uout2 x 0 ... 1 V/ 0 ... 5 V/      0... 10 V      Iout2 x 0 ... 20 mA V Analog outputs      current output      voltage output Digital outputs Ethernet interface (optional)      Supported standards      Connector      Protocols WLAN interface (optional)      Supported standards      Antenna connector type      Protocols      Security Authentication / Encryption      Open / no encryption      Open / WEP      WPA Pre shared key / TKIP      WPA Pre shared key / CCMP (a.k.a. WPA2) Optional data logger with real-time clock      Logged parameters      Logging interval      Max. logging period      Logged points      Battery lifetime Menu languages		10 ... 35 VDC, 24 VAC 100 ... 240 VAC 50/60 Hz max. 25 mA max. 25 mA max. 60 mA 0 ... 20 mA, 4 ... 20 mA 0 ... 1 V, 0 ... 5 V, 0 ... 10 V RS-232, RS-485 (optional) 10/100Base-T RJ45 Telnet 802.11b RP-SMA Telnet WEP 64/128,WPA max. three with trend/min/max values 10 sec (fixed) 4 years 5 months 13,7 million points per parameter min. 5 years English, French, Spanish, German, Japanese, Russian, Swedish, Finnish, Chinese
Mechanics
	Probe cable diameter      HMT333      other probes Material (housing) Housing classification	6.0 mm 5.5 mm G-AlSi 10 Mg (DIN 1725) IP65 (NEMA 4)