Vaisala MMT330 - Manual (Page 19)

Chapter 2 ___________________________________________________________ Product Overview
VAISALA ________________________________________________________________________ 19
CHAPTER 2
PRODUCT OVERVIEW
This chapter introduces the features, advantages, and the product
nomenclature of the Vaisala HUMICAP® Moisture and Temperature
Transmitter for Oil MMT330.
Introduction to MMT330
The MMT330 transmitter is a microprocessor based instrument for the
measurement of moisture in terms of water activity for example in the
lubrication of circulation systems or in transformer oil. The transmitter
incorporates a capacitive thin film sensor. The operation of the sensor is
based on changes in its capacitance as the thin polymer film absorbs
water molecules.
The transmitter can be configured in many ways. It can have either a
blank cover or a cover with a local display and keypad with which the
user can operate the transmitter. The power supply voltage can be
selected from three alternatives. Two analogue output signals can be
scaled and the measurement ranges changed within certain limits. The
MMT330 transmitter can be supplied probe cable lengths.
MMT330 also provides for accurate temperature measurement. It is an
easy-to-install on-line transmitter which can be calibrated against
traceable salt solutions.
Vaisala HUMICAP® Moisture and Temperature Transmitter for Oil
MMT330 provides reliable moisture measurement in 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.
Table 3 Quantities Measured by MMT330
Quantity Abbreviation Metric Unit Non-Metric Unit
Water activity AW
Temperature T ºC ºF