Vaisala HMT330 - Manual (Page 21)

Chapter 2 ___________________________________________________________ Product Overview
VAISALA ________________________________________________________________________ 19
CHAPTER 2
PRODUCT OVERVIEW
This chapter introduces the features, advantages, and the product
nomenclature of the Vaisala HUMICAP® Humidity and Temperature
Transmitter Series HMT330.
Introduction to HMT330
The HMT330 transmitter provides reliable humidity measurement in a
wide range of applications. Analog outputs can be chosen between
current and voltage signals. Alternatively, digital outputs RS-232
(standard) or RS-422/485 (optional) can be selected.
The quantities measured and calculated by HMT330 are presented in
Table 3 below. The quantities available as an option are presented in
Table 4 below.
Table 3 Quantities Measured by HMT330
Quantity Abbreviation Metric Unit Non-Metric Unit
Relative humidity (RH) RH %RH %RH
Temperature (T) T ºC ºF
Table 4 Optional Quantities Measured by HMT330
Quantity Abbreviation Metric Unit Non-Metric Unit
Dewpoint / Frostpoint
Temperature (T
d/f
)
TDF ºC ºF
Dewpoint Temperature (T
d
) TD ºC ºF
Absolute humidity (a) A g/m
3
gr/ft
3
Mixing ratio (x) X g/kg gr/lb
Wetbulb temperature (T
w
) TW ºC ºF
Humid air volume / dry air
volume (by volume or by
weight) (H
2
O)
H2O ppm
v
/ppm
w
ppm
v
/ppm
w
Water vapor pressure (P
w
) PW hPa lb/in
2
Water vapor saturation
pressure (P
ws
)
PWS hPa lb/in
2
Enthalpy (h) H kJ/kg Btu/lb
Difference of T and T
d/f
(∆T)
DT ºC ºF