Vaisala DRYCAP DMT340 SERIES User manual

USER'S GUIDE
Vaisala DRYCAP® Dewpoint and
Temperature Transmitter Series
DMT340
M210704EN-E

PUBLISHED BY
Vaisala Oyj Phone (int.): [phone]
P.O. Box 26 Fax: [phone]
FI-00421 Helsinki
Finland
Visit our Internet pages at http://www.vaisala.com/
© Vaisala 2009
No part of this manual may be reproduced in any form or by any means, electronic or
mechanical (including photocopying), nor may its contents be communicated to a third
party without prior written permission of the copyright holder.
The contents are subject to change without prior notice.
Please observe that this manual does not create any legally binding obligations for
Vaisala towards the customer or end user. All legally binding commitments and
agreements are included exclusively in the applicable supply contract or Conditions of
Sale.

________________________________________________________________________________
VAISALA________________________________________________________________________ 3
Table of Contents
CHAPTER 1
GENERAL INFORMATION..........................................................................13
About This Manual.................................................................13
Contents of This Manual.....................................................13
Version Information.............................................................14
General Safety Considerations...........................................14
Feedback.............................................................................14
Product Related Safety Precautions....................................15
ESD Protection....................................................................15
Recycling ................................................................................15
Regulatory Compliances.......................................................16
DNV Type Approval.......................................................16
Transmitters with LAN or WLAN Interface.....................16
Transmitters with WLAN Interface.................................17
Patent Notice ..........................................................................17
Trademarks.............................................................................17
License Agreement................................................................18
Warranty..................................................................................18
CHAPTER 2
PRODUCT OVERVIEW................................................................................19
Introduction to DMT340.........................................................19
Basic Features and Options................................................20
Structure of the Transmitter ................................................21
Probe Options .....................................................................23
CHAPTER 3
INSTALLATION............................................................................................25
Mounting the Housing ...........................................................25
Standard Mounting without Mounting Plate........................25
Wall Mounting with Wall Mounting Kit.................................26
Mounting with DIN Rail Installation Kit................................28
Pole Installation with Installation Kit for Pole or Pipeline ....29
Mounting the Rain Shield with Installation Kit.....................30
Panel Mounting Frame........................................................30
Wiring ......................................................................................32
Cable Bushings...................................................................32
Grounding the Cables.........................................................33
Transmitter Housing Grounding..........................................34
Signal and Power Supply Wiring.........................................34
Connections to a 24 VAC Power Supply ............................35
Probe Mounting......................................................................36
DMT342 Small-size Flanged Probe for Use with Sampling
Cell......................................................................................37
DMT344 For High-pressure Applications............................39

USER'S GUIDE____________________________________________________________________
4 ___________________________________________________________________ M210704EN-E
DMT347 Small Pressure-tight Probe...................................41
Pressure-Tight Swagelok Installation Kits for DMT347.......41
DMT348 For Pressurized Pipelines.....................................43
Tightening the Clasp Nut.....................................................45
Ball Valve Installation Kit for DMT348.................................46
Leak Screw Installation .......................................................49
Mounting the Probe Directly to the Process........................50
Sampling Cell for DMT348..................................................52
Optional Modules ...................................................................54
Power Supply Module .........................................................54
Installation......................................................................55
Warnings ........................................................................55
Galvanic Isolation for Output...............................................58
Installation......................................................................58
Third Analog Output ............................................................59
Installation and Wiring....................................................59
Alarm Relays.......................................................................60
Installation and Wiring....................................................60
Selecting the Activation State of the Relay....................61
RS-422/485 Interface ..........................................................62
Installation and Wiring....................................................62
LAN Interface.......................................................................64
WLAN Interface...................................................................65
Attaching the WLAN Antenna ........................................66
Data Logger Module............................................................66
8-pin Connector...................................................................69
CHAPTER 4
OPERATION.................................................................................................71
Getting Started........................................................................71
Display/Keypad.......................................................................71
Basic Display.......................................................................71
Graphic History....................................................................72
Menus and Navigation.........................................................74
Changing the Language.................................................75
Rounding Setting............................................................76
Display Backlight Setting................................................76
Display Contrast Setting.................................................76
Keypad Lock (Keyguard)................................................76
Menu PIN Lock...............................................................77
Factory Settings...................................................................77
Display Alarms.....................................................................78
Configuring a Display Alarm...........................................78
MI70 Link Program for Data Handling ..................................80
Serial Line Communication...................................................80
User Port Connection..........................................................81
Service Port Connection......................................................82
Connection Cables.........................................................82
Installing the Driver for the USB Cable ..........................82
Using the Service Port....................................................83
LAN Communication..............................................................84
IP Configuration...................................................................84
Using Display/Keypad....................................................85
Using Serial Line............................................................86
Wireless LAN Configuration................................................87
Using Display/Keypad....................................................87

________________________________________________________________________________
VAISALA________________________________________________________________________ 5
Using Serial Line............................................................89
Telnet Settings....................................................................89
Web Configuration for LAN and WLAN...............................90
Terminal Program Settings .................................................91
Opening a Serial/USB connection .................................91
Opening a Telnet session (LAN/WLAN)........................92
List of Serial Commands.....................................................94
Getting the Measurement Message from Serial Line .........96
Starting Continuous Outputting......................................96
R................................................................................96
Stopping Continuous Outputting....................................96
S................................................................................96
Formatting Serial Line Message .........................................97
FTIME and FDATE.........................................................97
FST ................................................................................97
General Settings.....................................................................98
Changing the Quantities and Units.....................................98
Using Display/Keypad....................................................98
Using Serial Line............................................................99
FORM.............................................................................99
UNIT.............................................................................100
Pressure Compensation Setting .......................................101
Using Display/Keypad..................................................101
Using Buttons on the Motherboard..............................102
Using Serial Line..........................................................102
XPRES and PRES..................................................102
Date and Time...................................................................103
Using Display/Keypad..................................................103
Using Serial Line..........................................................104
User Port Serial Settings...................................................104
SERI.............................................................................105
SMODE........................................................................105
INTV.............................................................................106
ECHO...........................................................................106
Data Filtering.....................................................................106
FILT..............................................................................107
Device Information............................................................107
? ...................................................................................108
HELP............................................................................109
ERRS...........................................................................109
VERS ...........................................................................109
Resetting the Transmitter Using Serial Line .....................110
RESET.........................................................................110
Locking Menu/Keypad by Using Serial Line .....................110
LOCK ...........................................................................110
Data Recording.....................................................................111
Selecting the Data Recording Quantities..........................111
DSEL............................................................................111
View Recorded Data.........................................................111
DIR...............................................................................112
PLAY............................................................................113
Deleting the Recorded Files..............................................114
UNDELETE..................................................................114
Analog Output Settings.......................................................114
Changing the Output Mode and Range............................114
Analog Output Quantities..................................................116
AMODE/ASEL..............................................................117

USER'S GUIDE____________________________________________________________________
6 ___________________________________________________________________ M210704EN-E
Analog Output Tests..........................................................118
ITEST ...........................................................................118
Analog Output Fault Indication Setting..............................119
AERR............................................................................119
Operation of Relays..............................................................120
Quantity for Relay Output..................................................120
Measurement-Based Relay Output Modes.......................120
Relay Setpoints............................................................120
Hysteresis.....................................................................121
Relay Indicating Transmitter Error Status .........................122
Enabling/Disabling the Relays...........................................123
Operation of the Indication LEDs ......................................124
Setting the Relay Outputs .................................................124
RSEL............................................................................125
Testing the Operation of Relays........................................126
RTEST..........................................................................127
Operation of the RS-485 Module.........................................127
Networking Commands................................................127
SDELAY .......................................................................128
SERI.............................................................................128
ECHO...........................................................................128
SMODE ........................................................................128
INTV .............................................................................129
ADDR ...........................................................................129
OPEN [nn]....................................................................130
CLOSE .........................................................................130
Sensor Functions .................................................................130
AutoCal..............................................................................130
Automatic AutoCal........................................................131
Manual AutoCal............................................................131
Sensor Purge.....................................................................131
Manual Sensor Purge...................................................132
Interval Purge...............................................................132
Power-up Purge ...........................................................133
PUR.........................................................................133
PURGE....................................................................133
Sensor Warming................................................................134
CHAPTER 5
MAINTENANCE..........................................................................................135
Periodic Maintenance...........................................................135
Cleaning ............................................................................135
Changing the Probe Filter .................................................135
Calibration and Adjustment...............................................135
Error States .......................................................................136
Technical Support ................................................................138
Return Instructions ..............................................................138
Vaisala Service Centers.......................................................139
CHAPTER 6
CALIBRATION AND ADJUSTMENT.........................................................141
Calibration.............................................................................141
User Calibration and Adjustment.......................................141
Opening and Closing the Adjustment Mode......................142

________________________________________________________________________________
VAISALA________________________________________________________________________ 7
Adjustment Information.....................................................143
CTEXT and CDATE.....................................................143
Adjusting Dewpoint Td/f .......................................................144
Two-point Relative Humidity Adjustment using
Display/Keypad.................................................................144
Two-point Relative Humidity Adjustment Using Serial Line146
One-point Dewpoint Adjustment Using Display/Keypad...146
One-point Dewpoint Adjustment Using Serial Line...........148
Adjusting Temperature........................................................149
Adjusting Temperature Using Display/Keypad .................149
Adjusting Temperature Using Serial Line .........................150
CT ................................................................................150
Adjusting Analog Outputs...................................................151
Adjusting Analog Outputs using Display/Keypad..............151
Adjusting Analog Outputs using Serial Line......................152
ACAL............................................................................152
CHAPTER 7
TECHNICAL DATA....................................................................................153
Specifications.......................................................................153
Performance......................................................................153
Operating Environment.....................................................154
Inputs and Outputs............................................................154
Mechanics.........................................................................155
Probe Specifications .........................................................155
Technical Specifications of Optional Modules ..................156
Power Supply Module..................................................156
Analog Output Module.................................................156
Relay Module...............................................................156
RS-485 Module............................................................157
LAN Interface Module ..................................................157
WLAN Interface Module...............................................157
Data Logger Module ....................................................157
Options and Accessories....................................................158
Dimensions (mm/inch).........................................................160
APPENDIX A
CALCULATION FORMULAS ....................................................................165

USER'S GUIDE____________________________________________________________________
8 ___________________________________________________________________ M210704EN-E
This page intentionally left blank.

________________________________________________________________________________
VAISALA________________________________________________________________________ 9
List of Figures
Figure 1 Transmitter Body......................................................................21
Figure 2 Inside the Transmitter...............................................................22
Figure 3 Probe Options ..........................................................................23
Figure 4 Standard Mounting...................................................................25
Figure 5 Mounting with Wall Mounting Kit..............................................26
Figure 6 Dimensions of the Plastic Mounting Plate (mm/inch)...............26
Figure 7 Mounting with Metal Wall Mounting Plate................................27
Figure 8 Dimensions of Metal Mounting Plate (mm/inch) ......................27
Figure 9 Mounting with DIN Rail Installation Kit.....................................28
Figure 10 Vertical Pole.............................................................................29
Figure 11 Horizontal Pole.........................................................................29
Figure 12 Mounting the Rain Shield with Installation Kit..........................30
Figure 13 Panel Mounting Frame.............................................................31
Figure 14 Panel Mounting Dimensions (mm/inch) ...................................31
Figure 15 Cable Bushings........................................................................32
Figure 16 Grounding the Screen of Electrical Cable................................33
Figure 17 Screw Terminal Block on the Motherboard..............................34
Figure 18 Connections to 24 VAC Power Supply.....................................36
Figure 19 DMT342 Installation (without the Sampling Cell).....................37
Figure 20 HMP302SC Optional Sampling Cell.........................................38
Figure 21 DMT344 Probe.........................................................................39
Figure 22 Tightening the Nut....................................................................40
Figure 23 Cleaning of the Tightening Cone..............................................40
Figure 24 DMT347 Probe with Swagelok Installation Kit .........................41
Figure 25 DMT347 Probe Installation to Pipeline with Swagelok
Installation Kit...........................................................................42
Figure 26 DMT348 Probe.........................................................................43
Figure 27 Leak Screw in the DMT348 Probe...........................................44
Figure 28 Sealing of Fitting Body into Process ........................................44
Figure 29 Tightening the Clasp Nut..........................................................45
Figure 30 Installing the DMT348 Probe Through a Ball Valve Assembly 47
Figure 31 Probe in Leak Screw Installation..............................................49
Figure 32 DM240FA with Probe...............................................................50
Figure 33 Example of Installing the Probe Directly on the Process Pipe.51
Figure 34 Sampling Cells DMT242SC2 and DMT242SC ........................52
Figure 35 Installing the Probe in High Temperatures...............................53
Figure 36 Power Supply Module ..............................................................54
Figure 37 Galvanic Output Isolation Module............................................58
Figure 38 Third Analog Output.................................................................59
Figure 39 Third analog output selection...................................................60
Figure 40 Relay Module ...........................................................................61
Figure 41 RS-485-Module........................................................................62
Figure 42 4-Wire RS-485 Bus ..................................................................63
Figure 43 LAN Interface Module...............................................................65
Figure 44 WLAN Interface Module...........................................................66
Figure 45 Data Logger Module.................................................................68
Figure 46 Wiring of the Optional 8-pin Connector....................................69
Figure 47 Basic Display............................................................................72
Figure 48 Graphical Display.....................................................................72
Figure 49 Graphical Display with Data Logger.........................................73
Figure 50 Main Views...............................................................................75
Figure 51 Display Alarm Active ................................................................78
Figure 52 Display Alarms .........................................................................79
Figure 53 Modifying an Alarm Limit..........................................................79

USER'S GUIDE____________________________________________________________________
10 __________________________________________________________________ M210704EN-E
Figure 54 Service Port Connector and User Port Terminal on the Mother
Board........................................................................................81
Figure 55 Connection Example Between PC Serial Port and User Port..82
Figure 56 Network Interface Menu ...........................................................85
Figure 57 IP Configuration Menu..............................................................85
Figure 58 Wireless LAN Settings..............................................................88
Figure 59 Entering Network SSID.............................................................88
Figure 60 Selecting the Wireless Network Type.......................................88
Figure 61 Web Configuration Interface for WLAN....................................91
Figure 62 Opening a Serial Connection....................................................92
Figure 63 Opening a Telnet Connection...................................................93
Figure 64 Pressure Set Buttons on the Motherboard.............................102
Figure 65 Following Device Information on the Display .........................107
Figure 66 Current/Voltage Switches of Output Modules ........................115
Figure 67 Measurement-Based Relay Output Modes............................120
Figure 68 FAULT/ONLINE STATUS Relay Output Modes.....................123
Figure 69 Relay Availability ....................................................................124
Figure 70 Following AutoCal on the Display...........................................131
Figure 71 Performing Manual Purge.......................................................132
Figure 72 Activating Start-up Purge........................................................133
Figure 73 Error Indicator and Error Message.........................................136
Figure 74 Starting the Adjustment..........................................................144
Figure 75 Performing Purge ...................................................................144
Figure 76 Following the RH Trend on Graphical Display .......................145
Figure 77 Ending Adjustment of Point 1.................................................145
Figure 78 Proceeding to Adjustment of Point 2......................................145
Figure 79 Completing Adjustment of Point 2..........................................145
Figure 80 Following Stabilization............................................................147
Figure 81 Proceeding with T d/f Adjustment............................................147
Figure 82 Completing T d/f Adjustment....................................................147
Figure 83 Dewpoint Accuracy Graph......................................................153
Figure 84 DMT340 Transmitter Body Dimensions .................................160
Figure 85 WLAN Antenna Dimensions...................................................161
Figure 86 Sampling Cell Dimensions......................................................161
Figure 87 DMT342 Probe Dimensions ...................................................162
Figure 88 DMT344 Probe Dimensions ...................................................162
Figure 89 DMT347 Probe Dimensions ...................................................163
Figure 90 DMT348 Standard Probe Dimensions....................................163
Figure 91 NPT 1/2" Nut Dimensions.......................................................164
Figure 92 DMT348 Optional 400mm Probe Dimensions........................164

________________________________________________________________________________
VAISALA_______________________________________________________________________ 11
List of Tables
Table 1 Manual Revisions.....................................................................14
Table 2 Application, Location Classes ..................................................16
Table 2 Quantities and Their Abbreviations..........................................19
Table 3 Optional Quantities and Their Abbreviations ...........................20
Table 4 DMT348 Probe Dimensions.....................................................44
Table 5 Connecting the Twisted Pair Wires to the Screw Terminals....63
Table 6 4-Wire (Switch 3:On)................................................................64
Table 7 2-Wire (Switch 3:Off)................................................................64
Table 8 Observartion Periods and Resolution ......................................67
Table 9 Wiring of the 8-pin connector ...................................................69
Table 10 Periods for Trend and Max/Min Calculations...........................73
Table 11 Graph Information Messages...................................................74
Table 12 Default Serial Communication Settings for the User Port........81
Table 13 Communication Settings for the Service Port ..........................83
Table 14 IP Settings for the LAN and WLAN Interfaces .........................84
Table 15 Wireless LAN Settings..............................................................87
Table 16 Measurement Commands........................................................94
Table 17 Formatting Commands.............................................................94
Table 18 Data Recording Commands.....................................................94
Table 19 Purge Commands ....................................................................95
Table 20 Autocalibration Commands......................................................95
Table 21 Calibration and Adjustment Commands...................................95
Table 22 Setting and Testing the Analog Outputs ..................................95
Table 23 Setting and Testing the Relays................................................95
Table 24 Other Commands.....................................................................95
Table 25 FORM Command Modifiers......................................................99
Table 26 Multiplication Factors..............................................................103
Table 27 Selection of Output Modes.....................................................105
Table 28 Filtering Levels.......................................................................106
Table 29 Error Messages......................................................................137
Table 30 Indicator Led Functions..........................................................142
Table 31 Options and Accessories........................................................158

USER'S GUIDE____________________________________________________________________
12 __________________________________________________________________ M210704EN-E
This page intentionally left blank.

Chapter 1 ________________________________________________________ General Information
VAISALA_______________________________________________________________________ 13
CHAPTER 1
GENERAL INFORMATION
About This Manual
This manual provides information for installing, operating, and
maintaining Vaisala DRYCAP®Dewpoint and Temperature Transmitter
Series DMT340.
Contents of This Manual
This manual consists of the following chapters:
- Chapter 1, General Information, provides general notes for the manual
and the product.
- Chapter 2, Product Overview, introduces the features, advantages, and
the product nomenclature of the DMT340.
- Chapter 3, Installation, provides you with information that is intended
to help you install the product.
- Chapter 4, Operation, contains information that is needed to operate
the product.
- Chapter 5, Maintenance, contains information that is needed in basic
maintenance of the product.
- Chapter 6, Calibration and adjustment, provides information and
instructions concerning the calibration and adjustment of the
DMT340.
- Chapter 7, Technical Data, provides the technical data of the product.
- Appendix A, Calculation Formulas, presents the equations used for
the calculated output quantities.

USER'S GUIDE____________________________________________________________________
14 __________________________________________________________________ M210704EN-E
Version Information
Table 1 Manual Revisions
Manual Code Description
M210704EN-A April 2005 - First release
M210704EN-B November 2006
M210704EN-C June 2007 - Data logger module and USB-RJ45
cable added as new options. Support for Chinese
language.
M210704EN-D May 2008 – New options added: LAN Interface,
WLAN Interface. Display Alarm feature added.
M210704EN-E June 2009 – Added PuTTY terminal application
instructions, revised description of the MI70 Link
software. Removed instructions for
HyperTerminal.
General Safety Considerations
Throughout the manual, important safety considerations are highlighted
as follows:
WARNING Warning alerts you to a serious hazard. If you do not read and follow
instructions very carefully at this point, there is a risk of injury or even
death.
CAUTION Caution warns you of a potential hazard. If you do not read and follow
instructions carefully at this point, the product could be damaged or
important data could be lost.
NOTE Note highlights important information on using the product.
Feedback
Vaisala Customer Documentation Team welcomes your comments and
suggestions on the quality and usefulness of this publication. If you find
errors or have other suggestions for improvement, please indicate the
chapter, section, and page number. You can send comments to us by e-
mail: [email protected]

Chapter 1 ________________________________________________________ General Information
VAISALA_______________________________________________________________________ 15
Product Related Safety Precautions
The DMT340 Dewpoint and Temperature Transmitter delivered to you
has been tested for safety and approved as shipped from the factory. Note
the following precautions:
WARNING Ground the product, and verify outdoor installation grounding
periodically to minimize shock hazard.
CAUTION Do not modify the unit. Improper modification can damage the product,
lead to malfunction, or make the product noncompliant with applicable
legislation.
ESD Protection
Electrostatic Discharge (ESD) can cause immediate or latent damage to
electronic circuits. Vaisala products are adequately protected against
ESD for their intended use. However, it is possible to damage the product
by delivering electrostatic discharges when touching, removing, or
inserting any objects inside the equipment housing.
To make sure you are not delivering high static voltages yourself:
- Handle ESD sensitive components on a properly grounded and
protected ESD workbench. When this is not possible, ground yourself
to the equipment chassis before touching the boards. Ground yourself
with a wrist strap and a resistive connection cord. When neither of the
above is possible, touch a conductive part of the equipment chassis
with your other hand before touching the boards.
- Always hold the boards by the edges and avoid touching the
component contacts.
Recycling
Recycle all applicable material.
Dispose of batteries and the unit according to statutory regulations. Do
not dispose of with regular household refuse.

USER'S GUIDE____________________________________________________________________
16 __________________________________________________________________ M210704EN-E
Regulatory Compliances
DNV Type Approval
The Vaisala DRYCAP® Dewpoint and Temperature Transmitter Series
DMT340 is found to comply with Det Norske Veritas' Rules for
Classification of Ships, High Speed & Light Craft and Det Norske
Veritas' Offshore standards.
Applicable tests carried out according to Standard for Certification
No. 2.4, April 2006.
Table 2 Application, Location Classes
Type DMT340
Temperature B
Humidity B
Vibration A
EMC B
Enclosure B/IP65
TYPE APPROVED PRODUCT
CERTIFICATE NO.: A-11440
Transmitters with LAN or WLAN Interface
This equipment has been tested and found to comply with the limits for a
Class B digital device, pursuant to Part 15 of the FCC Rules. These limits
are designed to provide reasonable protection against harmful
interference in a residential installation. Operation is subject to the
following two conditions: (1) this device may not cause interference, and
(2) this device must accept any interference, including interference that
may cause undesired operation of the device.
This equipment generates, uses and can radiate radio frequency energy
and, if not installed and used in accordance with the instructions, may
cause harmful interference to radio communications. However, there is

Chapter 1 ________________________________________________________ General Information
VAISALA_______________________________________________________________________ 17
no guarantee that interference will not occur in a particular installation. If
this equipment does cause harmful interference to radio or television
reception, which can be determined by turning the equipment off and on,
the user is encouraged to try to correct the interference by one or more of
the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receiver.
- Connect the equipment into an outlet on a circuit different from that to
which the receiver is connected.
- Consult the dealer or an experienced radio/TV technician for help.
Transmitters with WLAN Interface
This device has been designed to operate with a 2 dBi half-wave antenna.
Antennas with a gain greater than 2 dB are strictly prohibited for use with
this device. The required antenna impedance is 50 ohms.
To reduce potential radio interference to other users, the antenna type and
its gain should be so chosen that the equivalent isotropically radiated
power (e.i.r.p.) is not more than that permitted for successful
communication.
This Class [B] digital apparatus complies with Canadian ICES-003.
Cet appareil numérique de la classe [B] est conforme à la norme NMB-
003 du Canada.
Patent Notice
The Vaisala DRYCAP® Dewpoint and Temperature Transmitter Series
DMT340 is protected by, for example, the following patents and their
corresponding national rights:
Finnish patents 98861 and 99164, French patents 6650303 and 9504397,
German patents 69418174 and 19513274, Japanese patents 3585973 and
2801156, UK patents 0665303 and 2288465, U.S. patent 5607564.
Trademarks
DRYCAP®is a registered trademark of Vaisala Oyj.
Windows® is a registered trademark of Microsoft Corporation in the
United States and/or other countries.

USER'S GUIDE____________________________________________________________________
18 __________________________________________________________________ M210704EN-E
License Agreement
All rights to any software are held by Vaisala or third parties. The
customer is allowed to use the software only to the extent that is provided
by the applicable supply contract or Software License Agreement.
Warranty
For certain products Vaisala normally gives a limited one-year warranty.
Please observe that any such warranty may not be valid in case of
damage due to normal wear and tear, exceptional operating conditions,
negligent handling or installation, or unauthorized modifications. Please
see the applicable supply contract or Conditions of Sale for details of the
warranty for each product.

Chapter 2 __________________________________________________________ Product Overview
VAISALA_______________________________________________________________________ 19
CHAPTER 2
PRODUCT OVERVIEW
This chapter introduces the features, advantages, and the product
nomenclature of the Vaisala DRYCAP®Dewpoint and Temperature
Transmitter DMT340 Series.
Introduction to DMT340
The DMT340 transmitter measures dewpoint temperature accurately in a
measurement range from -60ºC to +80 ºC (-76 ... +176 ºF). The AutoCal
feature provides excellent long term stability of the measurement.
DMT340 incorporates the advanced DRYCAP®technology, which
enables reliable and high-performance dewpoint measurement.
Apart from the extended dewpoint measurement range the optional
modules provide for more flexibility. See Table 3 below for the
quantities that DMT340 measures and calculates. See Table 4 below for
the optional quantities measured by DMT340.
Table 3 Quantities and Their Abbreviations
Quantity Abbreviation Metric Unit Non Metric
Unit
Dewpoint/frost point
temperature (Td/f ) TDF ºC ºF
Mixing ratio (x) X g/kg gr/lb
Parts per million H2O ppmv/ ppmwppmv/
ppmw

USER'S GUIDE____________________________________________________________________
20 __________________________________________________________________ M210704EN-E
Table 4 Optional Quantities and Their Abbreviations
Quantity Abbreviation Metric Unit Non Metric
Unit
Relative humidity RH RH %RH %RH
Temperature T T ºC ºF
Dewpoint/frost point in the
atmospheric pressure (Td/f ) TDFA ºC atm ºF atm
Absolute humidity (a) A g/m3gr/ft3
Absolute humidity in standard
pressure and temperature (NTP) ANTP g/m3gr/ft3
Wet bulb temperature (Tw) TW ºC ºF
Water vapor pressure (Pw ) PW hPa lb/in2
Water vapor saturation pressure
(Pws) PWS hPa lb/in2
Enthalpy (h) H kJ/kg Btu/lb
Difference of T and Td/f (∆T) DT ºC ºF
Dewpoint temperature (Td )* TD ºC ºF
Dewpoint in the atmospheric
pressure (Td )* TDA ºC atm ºF atm
*use these parameters only if you need dewpoint over water below 0 ºC/32ºF and not
over ice (industry standard)
Basic Features and Options
DMT340 has the following basic features and options:
- Dewpoint measurement with AutoCal and sensor purge features
- Sensor warming in high humidities
- Two analog outputs and a serial interface
- Several probes for different applications
- User friendly multilingual display option
- Calculated output quantities available.
- Different probe mounting kits, sensor protection options and probe
cable lengts 2 m, 5 m or 10 m.
- USB connectivity for service connections via the optional
USB-RJ45 cable
- Optional modules:
- galvanic isolation for outputs
- AC mains power supply
- RS-485 serial line
- LAN and WLAN interfaces
- data logger module with real time clock
- additional analog output module
- alarm relay module