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Vaisala HMT331 Humidity and Temperature Transmitter

Humidity and Temperature Transmitter
HMT331

The Vaisala HUMICAP® Humidity and Temperature Transmitter HMT331 is the top-of-the-line wall-mounted transmitter for demanding HVAC and condition monitoring applications.

Compared to regular wall-mounted transmitters, the HMT331 offers, higher measurement performance, better chemical tolerance, advanced graphical display features, more powering options, more output options and a wider variety of output humidity parameters.

Graphical display of history and measurement trends
The HMT330 series features a large numerical and graphical display, allowing users to easily monitor operational data, measurement trends and one-year measurement history. The optional data logger with real time clock makes it possible to generate over four years of measured history, and zoom in on any desired time or time frame.

Outputs and power supply options for every need
The output options include three analog outputs, RS-232, RS-485, and alarm relays.

The voltage supply range is from 10 to 35 VDC. With an additional module, the transmitter can be connected to all universal mains AC supplies. The input/output cable can be fed through the back of the transmitter, which is a useful feature, especially for installations in clean rooms.

• For temperatures -40 ... +60 °C (-40 ... +140 °F)
• Application examples: clean rooms, pharmaceutical processes, greenhouses, swimming halls, museums and archives

Performance
Relative humidity
Measurement range
0 ... 100 % RH
Accuracy (including non-linearity, hysteresis, and repeatability)
with Vaisala HUMICAP® 180 or 180R
for typical applications
Accuracy (including non-linearity, hysteresis, and repeatability)
with Vaisala HUMICAP® 180 or 180R
for applications with chemical purge/warmed probe
at +15 ... +25 °C (59 ... +77 °F) ±1 %RH (0 ... 90 %)
±1.7 %RH (90 ... 100 %RH)
at -20 ... +40 °C (-4 ... +104 °F) ±(1.0 + 0.008 x reading) %RH
at -40 ... +180 °C (-40 ... +356 °F) ±(1.5 + 0.015 x reading) %RH
Factory calibration uncertainty (+20 °C) ± 0.6 % RH (0 ... 40 %RH)
± 1.0 % RH (40 ... 97 %RH)
(Defined as ±2 standard deviation limits. Small variations possible, see also calibration certificate.)
Response time (90 %) at +20 °C (+68 °F) 8 s / 17 s* with grid filter
in still air 20 s / 50 s* with grid + steel netting filter
40 s / 60 s* with sintered filter
Temperature
Accuracy at +20 °C (+68 °F) ± 0.2 °C (± 0.36 °F)
Accuracy over temperature range (measurement range depends on model)
Inputs and outputs
Operating voltage 10 ... 35 VDC, 24 VAC
with optional power supply module 100 ... 240 VAC, 50/60 HZ
Power consumption at +20 °C (Uin 24 VDC) RS-232 max. 25 mA
Uout 2 x 0 ... 1 V/0 ... 5 V/0 ... 10 V max. 25 mA
Iout 2 x 0 ... 20 mA max. 60 mA
display and backlight + 20 mA
during chemical purge max. 110 mA
during probe heating (HMT337) + 120 mA
Analog outputs (2 standard, 3rd optional) current output 0 ... 20 mA, 4 ... 20 mA
voltage output 0... 1 V, 0... 5 V, 0... 10 V
Accuracy of analog outputs at +20 °C ±0.05% full scale
Temperature dependence of the
analog outputs
±0.005%/°C full scale
External loads
current outputs RL < 500 ohm
0 ... 1 V output RL> 2 kohm
0 ... 5 V and 0 ... 10 V outputs RL> 10 kohm
Max. wire size 0.5 mm2 (AWG 20) stranded wires recommended
Digital outputs RS-232, RS-485 (optional)
Service connection RS-232, USB
Relay outputs (optional) 0.5 A, 250 VAC
Ethernet interface (optional)
Supported standards 10/100Base-T
Connector RJ45
Protocols Telnet
Software support Vaisala MI70 link
WLAN interface (optional) Supported standards 802.11b
Antenna connector type RP-SMA
Protocols Telnet
Security WEP 64/128,WPA
Software support Vaisala MI70 link
Authentication / Encryption (WLAN) 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 max. three with trend/min/max values
Logging interval 10 sec (fixed)
Max. logging period 4 years 5 months
Logged points 13.7 million points per parameter
Battery lifetime min. 5 years
Display LCD with backlight, graphic trend display of any parameter
LCD with backlight, graphic trend display
of any parameter
English, Chinese, Japanese, Spanish, German,
French, Swedish, Russian, Finnish
Cable bushing M20 x 1.5 for cable diameter
Measurement range 8 ... 11 mm/0.31 ... 0.43"
Conduit fitting 1/2" NPT
User cable connector (optional) M12 series 8-pin (male)
option 1 female plug with 5 m (16.4 ft) black cable
option 2 female plug with screw terminals
Probe cable diameter HMT333 (+80 °C) 6.0 mm
other probes 5.5 mm
Housing material G-AlSi 10 Mg (DIN1725)
Housing classification IP 65 (NEMA4)


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