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USER'S GUIDE
Vaisala DEWCAP®Precision SAW
Hygromete
DM500
M210205EN-D
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PUBLISHED BY
Vaisala Oyj Phone (int.): +358 9 8949 1
P.O. Box 26 Fax: +358 9 8949 2227
FIN-00421 Helsinki
Finland
Visit our Internet pages at http://www.vaisala.com/
© Vaisala 2006
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.
Page 3
________________________________________________________________________________
Table of Contents
CHAPTER 1
GENERAL INFORMATION............................................................................7
About This Manual...................................................................7
Version Information ............................................................... 7
Feedback............................................................................... 7
Safety......................................................................................... 8
General Safety Considerations ............................................. 8
Product Related Safety Precautions ..................................... 8
ESD Protection...................................................................... 9
Regulatory Compliances.........................................................9
Trademarks.............................................................................12
License Agreement................................................................12
Warranty..................................................................................12
CHAPTER 2
PRODUCT OVERVIEW................................................................................ 13
Product Description...............................................................13
Front Panels............................................................................ 15
Back Panels ............................................................................ 17
Optional Accessories and Spare Parts................................19
Factory Calibration and Service...........................................19
CHAPTER 3
FUNCTIONAL DESCRIPTION.....................................................................21
DM500 Principle of Operation...............................................21
Sensing Element ................................................................. 22
RF-Signal ............................................................................22
Contamination and Chemical Resistance ........................... 23
CHAPTER 4
GENERAL INFORMATION ABOUT SAMPLING AND RESULTS.............25
Gas Sampling .........................................................................25
Measuring in Overpressure...................................................26
The Effect of the Ambient Temperature on Cooling
Capacity...................................................................................27
The Effect of the Liquid Coolant Temperature on Cooling
Capacity...................................................................................28
The Effect of the Sample Gas Flow Rate on Cooling
Capacity and Result Deviation..............................................29
VAISALA ________________________________________________________________________ 1
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User's Guide ______________________________________________________________________
CHAPTER 5
INFORMATION ON OPTIONAL PARTS .....................................................31
Optional Heated Gas Tubes...................................................31
Optional External Temperature Sensor................................32
Wetted Materials of the Optional Parts ................................33
CHAPTER 6
SETTING UP FOR OPERATION .................................................................35
Connection of the DMI500 and DMP501 Units.....................35
Swagelok tube fittings' installation instructions ...................36
Connecting the Sample Gas Flow ........................................37
Selecting the Cooling Method...............................................38
Connecting the Cooling Liquid.............................................39
Connecting the Condensation Water Drain Tube ...............40
CHAPTER 7
MEASURING THE DEWPOINT ...................................................................41
Dewpoint Measurement with DM500 ..................................41
More About the Moisture Phases 67 ...................................42
CHAPTER 8
DISPLAYS AND MENUS .............................................................................45
Main View (In Measuring Mode)............................................45
Graphical Display ...................................................................46
Menus and Navigation ...........................................................47
CHAPTER 9
BASIC SETTINGS........................................................................................49
User Interface..........................................................................49
Setting the Language .......................................................... 49
Changing the Shortcut Keys................................................49
Key Click ON/OFF ............................................................... 50
Setting Date and Time............................................................50
Device Information.................................................................51
Reverting Factory Settings....................................................52
CHAPTER 10
DISPLAY SETTINGS....................................................................................53
Display Backlight....................................................................53
Selecting the Quantities and Units.......................................53
Hold/Save Display...................................................................54
Graphic Trend.........................................................................55
Contrast Adjustment..............................................................56
Alarm Sound ...........................................................................56
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CHAPTER 11
MEASUREMENT SETTINGS.......................................................................59
Automatic Frost Detection .................................................... 59
Forced Freezing......................................................................60
Cooling Method Air/Water.....................................................60
Statistical Filtering.................................................................61
Response Speed ....................................................................62
Pump ON/OFF.........................................................................62
Transient Recovery Time.......................................................63
Setting the Temperature, Pressure, and Flow Values........ 63
CHAPTER 12
SELF DIAGNOSTICS SETTINGS................................................................65
Salt Detection .........................................................................65
Sensor Circuit Check.............................................................66
Cooling Capacity Test............................................................67
Error History........................................................................... 68
CHAPTER 13
RECORDING DATA.....................................................................................69
Data Recording.......................................................................69
Stopping Recording............................................................... 70
Viewing Recorded Data .........................................................70
Checking the Recording Memory Status.............................70
Deleting All Record Files....................................................... 71
CHAPTER 14
OUTPUT INTERFACES...............................................................................73
Serial Communication Settings............................................74
Analog Outputs (Optional) .................................................... 75
Relay Outputs (Optional).......................................................77
CHAPTER 15
CALIBRATIOND AND ADJUSTMENT........................................................81
General About Calibration and Adjustments ...................... 81
Calibration Interval .............................................................. 81
Calibration Laboratory......................................................... 81
Calibrating DM500 Equipped with a Pump ......................... 82
Making an Adjustment........................................................... 82
CHAPTER 16
SERIAL LINE COMMANDS.........................................................................85
Serial Commands................................................................... 85
Output Commands (DMI500).................................................86
R Continuous Output ..................................................... 86
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User's Guide ______________________________________________________________________
S Stopping the Continuous Output.................................87
ADDR Setting the Device Address................................. 87
SEND Outputting One Single Reading ..........................87
INTV Setting the Output Interval .................................... 87
FORM Defining the Output Format ................................ 88
Operational Commands.........................................................91
START Starting the Measurement ................................. 91
STOP Stopping the Measurement .................................91
PUMP Starting/Stopping the Optional Sample Gas Pump91
HEAT Starting/Stopping the Optional Heater................. 92
SALT Enables/Disables the Salt Contamination Detection92
SCAL Starts the Salt Detection Limit Determination Cycle93
PTEST Starts the Cooling Capacity Test ....................... 93
ANAL Starts/Stops the Statistical Filtering ..................... 94
FFROST Enabled/Disables the Automatic Forced
Freezing Procedure........................................................94
Setting Commands.................................................................95
SERI Setting the Serial Communication Parameters..... 95
UNIT Setting the Units....................................................95
TIME Setting the Date and Time....................................96
RSEL Setting the Relays................................................ 96
ASEL Setting the Analog Outputs .................................. 97
AERR Setting the Invalid Output for Analog Channel....98
COOLER Setting the Cooling Method Status ................99
FLOW Setting the Flow Value........................................99
XFLOW Setting the Flow Value Temporarily ...............100
PRES Setting the Pressure..........................................100
XPRES Setting the Pressure Temporarily ...................100
TP Setting the Temperature.........................................101
XTP Setting the Temperature Temporarily ..................101
Adjustments..........................................................................102
CDP Adjusting Dewpoint Temperature (in 4 ... 10 points)102
CTP Adjusting the Dewpoint Temperature (in two points)104
FCAL Adjusting the Flow Meter (in one point) .............105
PCAL Adjusting the Pressure Sensor (in two points)...105
Others....................................................................................106
? Outputting the Device Settings.................................. 106
?? Outputting the Device Settings in POLL-State........106
DEL Deleting the Data Files.........................................106
DIR Outputting List of the Data Files............................106
ECHO Setting the Echo ON/OFF.................................106
ERRS Outputting the Error Messages .........................106
HELP Outputting the Commands.................................107
INIE Reverting the Factory Settings.............................107
SMODE Selecting the Operation Mode .......................107
OPEN & CLOSE Opening and Closing the Lines ........ 108
PLAY Outputting the Data File or History Memory ......108
SCC Sensor Circuit Check........................................... 109
SSC Sensor Status Check ...........................................109
SNUM Outputting the Serial Numbers of DM500 and
DMP501 .......................................................................109
VERS Outputting the Program Name and Version ...... 110
CHAPTER 17
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MI70 LINK PROGRAM............................................................................... 111
Installation ............................................................................111
Device Name MI70ÙDM500 ................................................111
Displayed Quantities............................................................ 112
Sensing Unit Status .............................................................112
Real-Time Quantities............................................................112
Real-Time Update Interval...................................................112
Chart......................................................................................112
CHAPTER 18
MAINTENANCE ......................................................................................... 113
Cleaning the Sensor.............................................................113
Error Messages ....................................................................115
Technical Support................................................................ 116
Return Instructions..............................................................116
CHAPTER 19
SPECIFICATIONS...................................................................................... 119
Measured Variables..............................................................119
Dewpoint Temperature ................................................ 119
External Temperature (Optional) .................................121
Integrated Pressure (Optional)..................................... 121
Integrated Flow (Optional) ........................................... 121
General..................................................................................121
DMP501 Dewpoint Sensing Unit.................................. 121
Options for DMP501 .................................................... 122
DMI500 User Interface Unit ......................................... 122
Options for DMI500...................................................... 123
Outputs.................................................................................. 123
Electromagnetic Compatibility ...........................................123
Dimensions (in mm)............................................................. 123
APPENDIX A
HUMIDITY THEORY...................................................................................127
Measured and Calculated Results of DM500.....................127
Water Vapor in Air................................................................ 127
Saturation Vapor Pressure..................................................128
Dewpoint Temperature (T
Frost Point Temperature (T
Partial Pressure of Water Vapor (P
) ................................................. 128
d
)...............................................128
f
) .................................129
w
Relative Humidity (RH).........................................................129
Mixing Ratio (x).....................................................................130
Absolute Humidity (a)..........................................................131
Absolute Humidity at NTP (aNTP) ......................................131
Wet Bulb Temperature......................................................... 131
Enthalpy (h)...........................................................................131
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Humid Air Volume/Dry Air Volume PPM
Effect of Pressure on Dewpoint..........................................132
Using a Condensation Hygrometer....................................132
List of Figures
Figure 1 DMI500 User Interface Unit Front Panel .................................. 15
Figure 2 DMP501 Dewpoint Sensing Unit Front Panel ..........................16
Figure 3 DMI500 User Interface Unit Back Panel...................................17
Figure 4 DMP501 Dewpoint Sensing Unit Back Panel...........................18
Figure 5 DM500 Operating Principle Illusrated....................................... 21
Figure 6 RF-Signal Input/Output Illustrated ............................................22
Figure 7 Effect of Ambient Air Temperature on Lowest Achievable Stable
Sensor Temperature................................................................. 27
Figure 8 Effect of Water Temperature on Lowest Achievable Stable
Sensor Temperature................................................................. 28
Figure 9 Effect of Sample Flow Rate on Lowest Achievable Sensor
Temperature .............................................................................29
Figure 10 Effect of Sample Flow Rate on Dewpoint Measurement at -
60 ºC.........................................................................................29
Figure 11 Mechanical Dimensions (in mm) for Optional Temperature
Sensor ......................................................................................32
Figure 12 Standard 6 mm Swagelok Tube Fitting with the Elbow
Connector in the DMP501 Back Panel.....................................36
Figure 13 ¼" Swagelok Adapter Fitting Connected to the Standard
Swagelok 6 mm Connector ......................................................37
Figure 14 DMP501 Back Panel, Connectors for Sample Gas.................. 37
Figure 15 DMP501 Back Panel, Connectors for Cooling Liquid...............39
Figure 16 Main View Display ....................................................................45
Figure 17 DM500 Graphical Display.........................................................46
Figure 18 DM500 Menus and Displays.....................................................47
Figure 19 DMI500 User Interface Unit Information...................................51
Figure 20 DMP501 Dewpoint Sensing Unit Information ........................... 51
Figure 21 DMI500 User Interface Unit Back Panel (Same as Figure 3)...73
Figure 22 Gas Flow Rate from the Humidity Generator ........................... 82
Figure 23 Dewpoint Temperature Measurement Repeatability..............120
Figure 24 Dewpoint Temperature Measurement Response Time .........120
Figure 25 Partial Pressure of Water Vapor Over Water and Ice ............129
Figure 26 Water Vapor Saturation Curves..............................................130
...........................132
v
List of Tables
Table 1 Manual Revisions ....................................................................... 7
Table 2 4-Wire Connection....................................................................74
Table 3 2-Wire Connection....................................................................74
6 ___________________________________________________________________ M210205EN-D
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Chapter 1 ________________________________________________________ General Information
CHAPTER 1
GENERAL INFORMATION
This chapter provides general notes for the product.
About This Manual
This manual contains instructions for performing accurate dewpoint
measurements with Precision SAW Hygrometer DM500.
Version Information
Table 1 Manual Revisions
Manual Code Description
M210205EN-A 1st version, August 2001
M210205EN-B 2nd version, April 2002
M210205EN-C 3rd version, February 2004
M210205EN-D 4th version, May 2005
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: manuals@vaisala.com
VAISALA ________________________________________________________________________ 7
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User's Guide ______________________________________________________________________
Safety
General Safety Considerations
Throughout the manual, important safety considerations are
highlighted as follows:
WARNING
CAUTION
NOTE
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 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 highlights important information on using the product.
Product Related Safety Precautions
The DM500 Precision SAW Hygrometer delivered to you has been
tested for safety and approved as shipped from the factory. Note the
following precautions:
WARNING
CAUTION
8 ___________________________________________________________________ M210205EN-D
Ground the product, and verify outdoor installation grounding
periodically to minimize shock hazard.
Do not modify the unit. Improper modification can damage the
product or lead to malfunction.
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Chapter 1 ________________________________________________________ General Information
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.
Regulatory Compliances
Tämä laite on pienjännitedirektiivin 73/23/ETY mukainen !
- Lue käyttöopas kokonaan ja huolellisesti ennen kuin käytät laitetta.
- Ennen kuin liität laitteeseen virran, varmista, että virtalähteen syöttöjännite on sama kuin laitteeseen liitetyssä
tuotetietokilvessä mainittu käyttöjännite.
- Kytke verkkojohto maadoitettuun pistorasiaan !
- DMP501- ja DMI500-laitteiden sisällä ei ole käyttäjän huollettavissa olevia osia. Vahingollisen jännitteen
aiheuttamien vahinkojen välttämiseksi laitetta ei saa avata kuin Vaisalan valtuuttama huoltohenkilöstö.
- Älä käytä laitetta yhdessä syttyvien, voimakkaasti reagoivien tai myrkyllisten kaasujen kanssa. Varmista
tuuletuksen riittävyys ennen laitteen käyttämistä muiden kaasujen kuin ilman kanssa.
- Älä kokoa laitetta ympäristössä, jossa järjestelmässä poistuva tiivistynyt vesi saattaa aiheuttaa vaaratilanteita
(esimerkiksi korkeajännitteisten virtalähteiden päällä).
- Kun lämmitintoiminto on käytössä, älä kosketa anturikammion kuumaa suojusta. Käytä hansikkaita, kun irrotat
suojuksen.
Den här produkten uppfyller lågspänningsdirektivet (73/23 EEC) !
- Läs igenom hela användarhandboken noga innan du använder produkten.
- Innan du ansluter produkten i vägguttaget, bör du kontrollera att nätspänningen överensstämmer med den
driftsspänning, som anges på typskylten som finns på produkten.
- Det finns inga delar inuti DMP501- eller DMI500-mätaren, som ska underhållas av användaren. För att undvika
att säkerhetsrisker uppstår med farlig spänning får höljet aldrig avlägsnas, utom av auktoriserad servicepersonal
från Vaisala.
VAISALA ________________________________________________________________________ 9
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User's Guide ______________________________________________________________________
- Anslut inte brandfarliga, mycket reaktiva eller giftiga gaser till instrumentet. Se till att ventilationen är tillräcklig
vid användning av andra gaser än luft.
- Sätt inte samman instrumentet i en lokal där kondensvatten som droppar ut ur systemet kan orsaka en farlig
situation, till exempel ovanpå högspänningsutrustning.
- Rör inte vid det heta locket på mätprobens kammare med fingrarna när uppvärmningsfunktionen har aktiverats.
Använd handskar när du ska ta av locket.
Dieses Produkt entspricht der Niederspannungsrichtlinie (73/23 EWG) !
- Lesen Sie die Bedienungsanleitung vor Verwendung des Geräts sorgfältig und vollständig durch.
- Vergewissern Sie sich vor dem Anschließen an eine Steckdose, dass die Netzspannung der Betriebsspannung
entspricht, die auf dem Typenschild des Produkts angegeben ist.
- Die Systeme DMP501 und DMI500 enthalten keine vom Benutzer zu wartenden Teile. Zur Vermeidung von
Sicherheitsrisiken durch gefährliche Spannungen darf das Gehäuse nur von befugtem Vaisala-Wartungspersonal
geöffnet werden.
- Halten Sie das Gerät von entflammbaren, hoch reaktiven und giftigen Gasen fern. Sorgen Sie bei Verwendung
anderer Gase als Luft für ausreichende Belüftung
- Montieren Sie das Gerät nicht an Orten, an denen aus dem System tropfendes Kondenswasser eine Gefahr
darstellen kann, wie z. B. über Hochspannungversorgungen.
- Bei aktivierter Heizfunktion darf der heiße Deckel der Sensorkammer nicht mit bloßen Händen angefasst
werden. Verwenden Sie zum Abnehmen des Deckels Handschuhe.
Ce produit est conforme à la Directive relative à la Basse Tension (73/23 EEC) !
- Bien lire le guide de l'utilisateur dans son intégralité avant utilisation.
- Avant de brancher dans une prise, vérifier que la tension électrique de fonctionnement correspond à la tension de
fonctionnement mentionnée sur la plaque signalétique attachée au produit.
- Le DMP501 ou le DMI500 ne contiennent pas de pièces susceptibles d'être réparées par l'utilisateur. Afin
d'éviter tout danger lié à la tension électrique, le boîtier ne peut être ouvert que par un employé de maintenance
autorisé de Vaisala .
- Ne pas raccorder à l'instrument tous gaz inflammables, réactifs ou toxiques. Veiller à une ventilation correcte
lors de l'utilisation de gaz différents de l'air.
- Ne pas assembler l'instrument dans un endroit où de l'eau condensée s'échappant du système pourrait provoquer
un danger, par exemple, au-dessus d'une alimentation en haute tension.
- Lorsque la fonction de réchauffage est activée, ne pas toucher le couvercle chaud de la chambre du capteur à
mains nues. Porter des gants pour détacher le couvercle.
Questo prodotto è conforme alla Direttiva sulla Bassa Tensione (73/23 EEC) !
- Si prega di leggere attentamente e completamente la guida per l'utente prima dell'uso.
- Prima del collegamento a una presa di corrente, controllate che il vostro voltaggio operativo corrisponda al
voltaggio operativo specificato nella targhetta indicatrice del prodotto.
- Il DMP501 o il DMI500 non contengono al loro interno parti utilizzabili dall'utente. Per evitare rischi alla
sicurezza con un voltaggio pericoloso, il coperchio non deve essere aperto se non dal personale autorizzato
Vaisala.
- Non collegate gas infiammabili, altamente reattivi o tossici allo strumento. Assicurate una ventilazione adeguata
quando gas diversi dall'aria vengono usati.
10 __________________________________________________________________ M210205EN-D
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Chapter 1 ________________________________________________________ General Information
- Non posizionate lo strumento in un luogo dove l'acqua condensata che fuoriesce dal sistema potrebbe causare un
pericolo, come su alimentatori elettrici ad alto voltaggio.
- Quando la funzione di riscaldamento è attiva, non toccate a mani nude il tappo caldo della camera di
misurazione. Si prega di usare dei guanti per togliere il tappo.
Este producto cumple con la Directiva sobre baja tensión (73/23 CEE) !
- Lea todo el manual de usuario atentamente antes de utilizar el producto.
- Antes de enchufarlo a un conector, compruebe que el voltaje operativo corresponde al que se menciona en el tipo
de placa que se adjunta al producto.
- En DMP501 y en DMI500 no existen partes que puedan resultar prácticas para el usuario. Para evitar que se
produzcan accidentes debidos a tensiones peligrosas, únicamente el personal del servicio autorizado de Vaisala
podrá abrir la carcasa.
- No conecte al instrumento gases tóxicos, muy reactivos o inflamables. Asegúrese de que la ventilación es la
adecuada al utilizar gases que no sean aire.
- No monte el instrumento en una ubicación donde el vapor del agua condensada pueda provocar algún peligro
como, por ejemplo, en la parte superior de una fuente de alimentación de alto voltaje.
- Cuando se activa la función del calentador, no toque la tapa caliente de la cámara del sensor con las manos sin
protección. Utilice guantes cuando vaya a quitar la tapa.
Dette produkt over direktivet om svagstrøm (73/23 EEC) !
- Læs hele brugervejledningen omhyggeligt, før du tager enheden i brug.
- Før du tilslutter enheden til en stikkontakt, skal du kontrollere, at den lokale spænding svarer til den spænding,
der er angivet på pladen med produktoplysninger.
- Der er ingen dele inde i DMP501 eller DMI500, som kan efterses af brugeren. Med henblik på at undgå risiko
for skader, er delene med farlig spænding afdækket, og kabinettet på må kun fjernes af autoriserede Vaisalaserviceteknikere.
- Undgå, at brændbare, højreaktive og giftige luftarter kommer i nærheden af enheden. Sørg for tilstrækkelig
udluftning, når der benyttes andre luftarter end almindelig luftluft.
- Undgå at montere enheden et sted, hvor kondenseret vand kan dryppe ud af systemet og forårsage skader, f.eks.
over et stærkstrømsstik.
- Når varmefunktionen er aktiveret, skal du undgå at berøre topdækslet på sensorkammeret med bare hænder.
Brug handsker, når du tager dækslet af.
Dit product voldoet aan de La agspanningsrichtlijn (73/23 EEC) !
- Lees de volledige gebruikershandleiding aandachtig door voordat u het apparaat in gebruik neemt.
- Voordat u het apparaat op een stopcontact aansluit, controleert u of de plaatselijke bedrijfsspanning overeenkomt
met de bedrijfsspanning die wordt vermeld op het typeplaatje dat op het product is bevestigd.
- Er bevinden zich geen onderdelen in de DMP501 of DMI500 die door de gebruiker kunnen worden
onderhouden. Om veiligheidsrisico's als gevolg van gevaarlijke spanningsniveaus te voorkomen, mag de
behuizing alleen worden geopend door bevoegd onderhoudspersoneel van Vaisala.
- Sluit geen brandbare, sterk reactieve of giftige gassen aan op het instrument. Zorg voor voldoende ventilatie
wanneer u met andere gassen dan lucht werkt.
- Monteer het instrument niet op een locatie waar condenswater dat uit het systeem druppelt tot een gevaarlijke
situatie kan leiden, zoals boven op voedingseenheden met hoge spanning.
VAISALA _______________________________________________________________________ 11
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User's Guide ______________________________________________________________________
- Raak het hete kapje van de sensorbehuizing niet met blote handen aan als de verwarmingsfunctie is geactiveerd.
Maak het kapje alleen los met handschoenen aan.
Trademarks
Microsoft®, Windows®, and Windows NT® are registered
trademarks of Microsoft Corporation in the United States and/or other
countries.
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.
12 __________________________________________________________________ M210205EN-D
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Chapter 2 __________________________________________________________ Product Overview
CHAPTER 2
PRODUCT OVERVIEW
This chapter introduces the features and advantages of Precision SAW
Hygrometer DM500.
Product Description
DM500 is a high accuracy dewpoint temperature measuring
instrument capable of measuring dewpoints down to -75 ºC with an
accuracy of ± 0.2 ºC.
The DM500 system consists of the user interface unit DMI500 and the
dewpoint sensing unit DMP501. Four of the following quantities can
be displayed at a time:
- Dewpoint/frostpoint T
on page 128.
- Dewpoint T
- Partial water vapour pressure P
- Humid air volume/dry air volume H2O (ppmv)
- Relative humidity RH (%)
- Wet-bulb temperature Tw (ºC or ºF)
- Absolute humidity a (g/m3 or gr/ft3)
- Mixing ratio x (g/kg or gr/lb)
(ºC or ºF)
d
(ºC or ºF), more about dewpoint/frostpoint
d/f
(mbar)
w
- Enthalpy h (kJ/kg or btu/lb)
- Difference of T and T
- Temperature T (ºC or ºF)
- Pressure P (bar, hPa, psi, torr)
VAISALA _______________________________________________________________________ 13
T (ºC or ºF)
d/f
Page 16
User's Guide ______________________________________________________________________
- Air flow rate flow (slpm, scfh)
The DM500 system includes two packages including the following
parts:
DMI500
- DMI500 user interface unit
- Serial cable for EIA-232 (RS232)
- CD-Rom including MI70 Link software; to transfer logged data to
your PC
- Power cable (according to the customer's requirement)
DMP501
- DMP501 dewpoint sensing unit
- Swagelok spare tube fittings for 1/4" tubes for the sample gas line
(to replace default tube fittings (6 mm)
- Allen key; to remove the sensor cap and to adjust the sample flow.
- Water tubing for the condense water outlet
14 __________________________________________________________________ M210205EN-D
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Chapter 2 __________________________________________________________ Product Overview
Front Panels
Figure 1 DMI500 User Interface Unit Front Panel
The following numbers refer to Figure 1 above:
1 = Mains switch . Press to turn the device on/off.
2 = Configurable softkeys . Press down to activate the menu
function shown beside the button.
3 = Arrow keypad ►. Press any of the arrow buttons to open
path for the menus. In the menus, you can navigate with
arrow buttons. Up and down arrows for moving in the menu,
right-pointing arrow for selecting menu item, left-pointing
arrow for returning to previous menu.
4 = Numeric keypad. Numerical input can be given with the
number keypad.
VAISALA _______________________________________________________________________ 15
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User's Guide ______________________________________________________________________
Figure 2 DMP501 Dewpoint Sensing Unit Front Panel
The following numbers refer to Figure 2 above:
NOTE
1 = Power/data cable; connect to the back panel of the DMI500.
2 = Allen screw for adjusting the sample flow.
3 = Sensor cup; three Allen screws to open the cup for sensor
cleaning.
Warranty is void if DMP501 or DMI500 case is opened by the user!
16 __________________________________________________________________ M210205EN-D
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Chapter 2 __________________________________________________________ Product Overview
Back Panels
1
C NO NC
REL 1
6
Figure 3 DMI500 User Interface Unit Back Panel
The following numbers refer to Figure 3 above:
1 = Relay outputs (optional)
2 = Serial port (EIA-232, RS232 for Terminal/MI70-link
3 = Connection to DMP501
4 = Mains cable
5 = RS485 and LonWorks-port (optional)
6 = Analog outputs (optional)
C NO NC
REL 2
5
2
3
4
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User's Guide ______________________________________________________________________
3
4
2
1
Figure 4 DMP501 Dewpoint Sensing Unit Back Panel
5
6
7
8
9
NOTE
The following numbers refer to Figure 4 above:
1 = Water In (WI)
2 = Gas In (GI)
3 = Connection to DMI500
4 = Relay for heated sample lines
5 = Water Out (WO)
6 = Temperature sensor connection (optional)
7 = Service switch 4: Adjustment enable switch
8 = Gas Out (GO)
9 = Serial port EIA-232, RS232
The DM500 shall always be operated in horizontal position or in
position where the device is supported by the handle, see picture on
page 125.
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Chapter 2 __________________________________________________________ Product Overview
Optional Accessories and Spare Parts
Description Order code
Accessories
Rack mounting kit DM500RMP
Portability kit DM500PAK
Extension cable 2.5 m DM500ECS
Extension cable 10 m DM500ECL
Mains EURO 6543
Mains UK 210548
Mains US/Japan 210547
Mains AUS 210619
Spare Parts
PTFE coated O-ring at gas inlet 210493
Factory Calibration and Service
WARNING
Please note that there are no user-serviceable parts inside the
DMP501 or DMI500. To avoid safety risks with hazardous voltage
or hazardous energy, the enclosures shall not be opened except by
authorized Vaisala service personnel.
NORTH AMERICAN SERVICE CENTER
Vaisala Inc., 100 Commerce Way, Woburn, MA 01801-1068, USA.
Phone: +1 781 933 4500, Fax +1 781 933 8029
Email: us-customersupport@vaisala.com
EUROPEAN SERVICE CENTER
Vaisala Instruments Service, Vanha Nurmijärventie 21 FIN-01670
Vantaa, FINLAND.
Phone: +358 9 8949 2758, Fax +358 9 8949 2295
E-mail: instruments.service@vaisala.com
ASIAN SERVICE CENTER
Vaisala KK, 42 Kagurazaka 6-Chome, Shinjuku-Ku, Tokyo 162-0825,
JAPAN.
Phone: +81 3 3266 9611, Fax +81 3 3266 9610
E-mail: aftersales.asia@vaisala.com
www.vaisala.com
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Chapter 3 ______________________________________________________ Functional Description
CHAPTER 3
FUNCTIONAL DESCRIPTION
This chapter describes the functionality of the product.
DM500 Principle of Operation
DM500 is an automatic, continuously controlling condensation
hygrometer designed to measure dewpoint temperatures from -75 ºC
to +60 ºC, depending on the model. The system consists of the
DMP501 dewpoint sensing unit and the DMI500 user interface unit.
The measured gas flows through the sensing unit, where it contacts a
temperature controlled quartz surface. The quartz surface is monitored
for the presence of condensation. The presence or absence of
condensation is sensed using surface acoustic wave (SAW)
technology. In the measuring mode, the temperature of the quartz
surface is varied until condensation exists in equilibrium. Temperature
of the sensor element is measured with a temperature sensor (1/3 DIN
B, Pt100, 4-wire) bonded on the backside of the quartz substrate. This
measured value is used to accurately output the dew/frostpoint
temperature.
Figure 5 DM500 Operating Principle Illusrated
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User's Guide ______________________________________________________________________
Sensing Element
The DEWCAP® SAW sensor, as used in the condensation
hygrometer, integrates the cooled surface (where condensation forms)
with the detection mechanism in one element. The element consists of
a transmitting and a receiving antenna photolithographically patterned
on a single mechanically very durable crystal quartz chip.
RF-Signal
A radio frequency (RF) signal fed to the transmitting antenna is
converted to a micromechanical wave. The mechanical wave
propagates along the sensing element surface to the receiving antenna,
where the mechanical wave is re-converted to a RF-signal. As the
wave propagates at the sensor surface only, it is very sensitive to
condensation in contact with the surface.
The presence of liquid condensation on the element alters the
signature in a repeatable way. The freezing of the condensation on the
element causes a distinctly different signal change, thus enabling the
determination of whether dew or frost is on the element.
Figure 6 RF-Signal Input/Output Illustrated
Analysis of the received wave in terms of frequency and amplitude
provides the information required to control the element's temperature
in such a way that a thin layer of dew or frost remains in equilibrium
on the element. Additionally, analysis can determine the presence or
absence of hygroscopic contaminants on the element.
Hygroscopic dirt like salt is a common source of error in conventional
dewpoint measurement techniques. The DEWCAP? sensor can detect
the presence of salts on the sensor surface. The salt sensing selfdiagnostics can be turned on/off by the user.
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Chapter 3 ______________________________________________________ Functional Description
Contamination and Chemical
Resistance
The DM500 operates reliably even with substantial particulate
contamination on the sensing element. Analysis of frequency and
impedance makes it possible to distinguish between frost and dew and
to give warning of hygroscopic contaminants on the detector.
Use of a quartz wafer as a sensor substrate results in excellent
resistance to aggressive chemicals. Wetted parts inside the DMP501
dewpoint sensing unit are limited to stainless steel, silicone, tantalum,
quartz, Vectra® (Liquid Crystal Polyester).
Vectra and silicone parts as well as those optional components that
have water-absorbing materials are located downstream from the
active area of the sensor thus not disturbing the measurement
especially in low dewpoints.
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Chapter 4 _________________________________ General Information About Sampling and Results
CHAPTER 4
GENERAL INFORMATION ABOUT
SAMPLING AND RESULTS
This chapter provides you with useful information concerning gas
sampling and the effects that different parameters have on the
measurement results.
Gas Sampling
When measuring low dewpoints, all installations must comply with
the strict requirements. Clean environment is always beneficial for
humidity measurements, but this is especially critical at very low
humidities. It is important to use high quality stainless steel tubes
(electropolished), particularly clean and dry. Contamination has often
a hygroscopic effect. Attention must be paid to correct and tight gas
connections. The ambient temperature and the temperature of all parts
of the sampling pathway must be kept above the dewpoint to avoid
condensation.
The following recommendations shall be taken into account when
measuring in very dry environments.
- Minimize the number of connections to avoid leaks
- Ensure that flow rate is adequate
- Avoid dead ends as they cannot be flushed easily
- The temperature of the gas line components must never lie under
the dewpoint of the sample gas, as this leads to condensation and
false results
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User's Guide ______________________________________________________________________
- Sample tubing shall be as short as possible, the surface area should
be minimized by using the tubing with the smallest diameter that
the flow conditions shall permit
- Surface finishing of wetted surfaces is important, polished or
electropolished steel is recommended for best results
- Avoid hygroscopic materials in the sampling lines, use stainless
steel membranes instead of rubber membranes
- Choose impermeable materials to avoid inward diffusion of
moisture through sampling tubes and enclosures, such impermeable
materials include high quality stainless steel and metals. Avoid
PVC or nylon tubes !
- PTFE (Teflon) tubes are not suitable for dewpoints below -40 ºC.
Measuring in Overpressure
When sampling in pressurized processes, the pressure difference
between the gas inlet and outlet ensures gas flow to the sensor.
However, please take into account the following:
- The dewpoint is measured always in the actual pressure. The
pressure is released at the flowmeter valve after the sensor
chamber. When measuring at overpressure, it must be taken into
account that the volume flow rate decreases under pressure,
whereas mass flow rate remains constant.
- The pressure ranges of the optional parts are:
- Integrated pressure sensor: 0...2 bar or 0...20 bar
- Integrated flow sensor: 1.7 bar
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Chapter 4 _________________________________ General Information About Sampling and Results
The Effect of the Ambient Temperature on
Cooling Capacity
The cooling capacity of the sensor is dependent on the cooling air
temperature, as shown in Figure 7. In general, the cooler the ambient
air is, the lower dewpoint can be reached. By using air as a cooling
medium, the lowest normally achievable dewpoint is about -50 ºC.
When measuring lower dewpoint, water cooling must be used.
Recommended air temperature: 10...40 ºC (50...104 ºF), depending on
the measured dewpoint.
Water cooling is recommended when measuring dewpoints > +40 ºC
(+104 ºF).
Figure 7 Effect of Ambient Air Temperature on Lowest
Achievable Stable Sensor Temperature
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The Effect of the Liquid Coolant Temperature
on Cooling Capacity
The cooling capacity of the sensor is dependent on the cooling water
temperature, as shown in Figure 8. Recommended water temperature:
< 15 ºC (50 ºF).
Figure 8 Effect of Water Temperature on Lowest Achievable
Stable Sensor Temperature
Sample gas flow in the above Figure 8 1.0 slpm; T
flow 5 l/min.
23 ºC; water
amb
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Chapter 4 _________________________________ General Information About Sampling and Results
The Effect of the Sample Gas Flow Rate on
Cooling Capacity and Result Deviation
The cooling effect of the gas flow rate is
shown in Figure 9 (on the right). Low flow
rate increases cooling capacity but also
increases response time.
The sample flow rate has an effect on the
deviation of the measurement results as
shown in Figure 10 (on the right).
Sample flow rate range: 0.5...1.5 slpm.
Recommended sample flow rate: 1.0 slpm.
-72
-73
-74
-75
-76
Tsensor /C
-77
-78
-79
0 0.5 1 1.5 2 2.5
Flow l/min
Figure 9 Effect of Sample Flow Rate on Lowest
Achievable Sensor Temperature
0.2
0.15
0.1
0.05
0
-0.05
deviation/°C
-0.1
-0.15
-0.2
0.5 0.75 1 1.25 1 .5
flow/slpm
Figure 10 Effect of Sample Flow Rate on
Dewpoint Measurement at -60 ºC
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Chapter 5 ________________________________________________ Information On Optional Parts
CHAPTER 5
INFORMATION ON OPTIONAL PARTS
This chapter provides you with information on the optional parts of
the DM500.
The following optional parts are
gas outlet
available for the DM500:
- Heated gas tubes (internal)
- External temperature sensor
optional pump
- Sampling pump
- Pressure sensor
- Flowmeter
optional internal
flow meter
DMP501 internal ONV
(output needle valve)
adjusted from
front panel
Optional Heated Gas Tubes
gas inlet
high pressure
optional pressure sensor
DEWCAP
dewpoint sensor
Heated gas tubes shall be used if the measured dewpoint is high, close
or above ambient temperature. It is recommended to use heated gas
tubes already for dewpoints 5 ºC (9 ºF) below ambient temperature.
Internal gas tubes
The optional heated gas tubes keep the internal gas tubes and sensor
chamber temperature above 60ºC.
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User's Guide ______________________________________________________________________
External gas tubes
The heating of the external gas tubes shall be taken care by the user.
The external lines shall be heated before letting the sample gas flow in
the lines. This is to avoid condensation problems. To facilitate
external gas line heating control, the relay output on the back plate of
the DMP501 activates when heating is ON. In order to keep the gas
connections warm enough the external gas line should be heated
100ºC above ambient and the connections shall be insulated. The
maximum dewpoint measurable with the heated internal gas sampling
is 35 ºC above the ambient temperature.
NOTE
After switching on the heating option, allow the system to warm up at
least 30 minutes to ensure that no condensation occurs in the gas
tubes.
WARNING
When heater function is activated, don't touch with bare fingers the
hot cap of the sensor chamber. Please use gloves when detaching the
cap.
Optional External Temperature Sensor
The external temperature sensor option is needed for temperature or
relative humidity (%RH) measurements.
Temperature measurement range -40…+80 °C (-40…+176 °F)
Typical accuracy ±0.1 °C (±0.18 °F)
Sensor Pt100 PRT DIN IEC 751 class ¼ B
Cable length 2 m/5 m/10 m
64
Ø 1.3
ø6
Ø 5.5
93
cable length
2 /5 /10meters
Figure 11 Mechanical Dimensions (in mm) for Optional
Temperature Sensor
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Chapter 5 ________________________________________________ Information On Optional Parts
Wetted Materials of the Optional Parts
Pump Polyarylamide, NBR (nitril butyl
rubber), galvanized steel.
Integrated pressure sensors Stainless steel (AISI 316)
Integrated flow sensor Silicon nitride, polyethermide,
fluorocarbon, aluminium, oxide,
epoxy, silicon, gold
External temperature sensor Glass, stainless steel, silicone
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Chapter 6 _____________________________________________________ Setting up for Operation
CHAPTER 6
SETTING UP FOR OPERATION
This chapter provides you with information that is intended to help
you set up the product for operation.
Connection of the DMI500 and DMP501 Units
Unpack the instrument carefully and check that all parts are visually
undamaged.
Connect the DMP501 dewpoint sensing unit to the DMI500 user
interface unit as follows:
- Insert the male connector at the end of the DMP501 power cable
(see Figure 2 on page 16, item 1) into the female connector on the
back panel of the DMI500 unit. Tighten the sleeve nut (and
simultaneously press the connector in) until the connectors are
perfectly mated. If the sensing unit is not connected properly, lines
replace the measured values on the display.
- Connect the serial output cable, analog output data cable (back
panel of the DMI500) and relay connections (back panel of the
DMI500), when used. See the ports from page 17 Back Panels.
- Connect the DMI500's grounded power supply cable (provided) to
the grounded box.
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User's Guide ______________________________________________________________________
Swagelok tube fittings' installation
instructions
1. Insert the tubing into the Swagelok tube
fitting. Tubing should rest firmly on the
shoulder of the fitting. The nut should be
finger tight.
2. Mark the nut at the 6 o'clock position.
3. Hold the fitting body with a backup wrench
and tighten the nut 1¼ turns. Watch the
marking and make one complete turn and
continue to 9 o'clock position.
CAUTION
The DM500 as delivered from the factory has 6 mm Swagelok tube
fittings. If you use ¼" tubing, always use the proper ¼" adapter
fitting (provided). Make sure the adapter is connected the right way.
An incorrectly connected adapter or connecting ¼" tubes straight into
the 6 mm tube fittings may lead to product damage. See Figure 12
and Figure 13 for visual instructions.
Figure 12 Standard 6 mm Swagelok Tube Fitting with the
Elbow Connector in the DMP501 Back Panel
Figure 12 shows the standard set-up of the DMP501 back panel.
Figure 13 illustrates the correct way of connecting ¼" tubing to the 6
mm tube fitting.
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Chapter 6 _____________________________________________________ Setting up for Operation
Figure 13 ¼" Swagelok Adapter Fitting Connected to the
Standard Swagelok 6 mm Connector
The following numbers refer to the enlarged area of Figure 13 above:
1 = Grooves
2 = No groove
To connect the ¼" adapter fitting, first disconnect the standard elbow
fitting. Notice how the millimeter-fittings have small grooves on
them. When the grooves face, the adapter fitting is connected the right
way. The inch-side of the adapter fitting has no groove on it.
Connecting the Sample Gas Flow
1
2
Figure 14 DMP501 Back Panel, Connectors for Sample Gas
The following numbers refer to Figure 14 above:
1 = Gas In (GI)
2 = Gas Out (GO)
1. Detach the Swagelok fittings from Gas In (GI) and Gas Out
(GO) connections. If the sample gas can flow out to measuring
room, it is not necessary to connect the GO fitting. Replace the
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User's Guide ______________________________________________________________________
6 mm fitting with the ¼" adapter fitting (provided), if needed. If
you use the adapter fitting, see that the 6 mm side is connected
to the Gas In -connection.
2. Attach the gas tubes (diameter of 6 mm or ¼") to the Swagelok
fittings.
3. Replace the Swagelok fitting (with the tubing) into the GI
connector (connect the Gas Out tubing similarly, if necessary).
NOTE
WARNING
When measuring high dewpoint temperatures with heated lines, the
connection fitting shall be insulated carefully to prevent
condensation.
4. Let the sample gas flow with a flow rate of 0.5...1.5 slpm
(recommended 1.0 slpm)
5. If needed, adjust the sample flow rate by turning the Allen screw
(in the sensor cup, see Figure 2 on page 16, item 2) with a key
(provided).
Do not connect flammable, highly reactive or toxic gases to the
instrument. Ensure adequate ventilation when using other gases than
air.
Selecting the Cooling Method
Use either air or water in sensor cooling.
- water cooling: generally required when measuring dewpoint below
-50 ºC (-58 ºF) and recommended when measuring dewpoints
higher than +40 ºC (+104 ºF)
Use of subzero water/glycol or ethanol mixture, as the cooler liquid is
not recommended, as there is a risk of substantial ice formation inside
the sensing unit. However, subzero cooling liquid can be used for
short periods. To ensure sufficient cooling capacity, please follow the
instructions below. The temperature of the cooling air/water and flow
rate of the sample gas has an effect on the cooling capacity.
When using air cooling, the fan inside the device is cooling the
system. When using water cooling, connect the water as instructed in
the following chapter.
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Chapter 6 _____________________________________________________ Setting up for Operation
NOTE
To avoid condensation into the internal gas tubes and sensor, stop
cooling water flow if measurement is stopped and Td of sample gas
may be higher than the cooling water temperature.
Connecting the Cooling Liquid
2
1
Figure 15 DMP501 Back Panel, Connectors for Cooling
Liquid
The following numbers refer to Figure 15 above:
1 = Water In (WI)
2 = Water Out (WO)
1. Remove the Swagelok fittings from Water In (WI) and Water
Out (WO) connections.
2. Attach the tubes (diameter of 8 mm) to the Swagelok fittings
(diameter of 8 mm or 5/16"). Plastic tubes are recommended.
3. Connect the water inflow tubing to the connector WI. And
similarly the water outflow tubing to connector WO. Reverse
water flow can be used as well.
4. Replace the Swagelok fittings to the back panel connectors.
5. Let the water flow with the flow rate of 5...20 l/min, temperature
of water shall be <+15 ºC (50 ºF). Check for leaks and tighten if
necessary.
Once the water tube connections have been tightened, the water tubing
should be disconnected from the Swagelok fittings.
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Connecting the Condensation Water Drain
Tube
Significant moisture condensation occurs only if the system is watercooled. Connect the condensation water drain tube to the outlet
situated on the right-side panel of the DMP501.
1. Connect the silicone tube to the metal tube protruding from the
right side of the DMP501 Dewpoint Sensing Unit.
2. The tube end must be placed at least 300 mm below the sensing
unit bottom level, in a drain or in a small vessel where the
condensed moisture can be safely drained. The amount of
condensed moisture is small, typically tens of milliliters per 24 h
of operation.
WARNING
Do not assemble the instrument in a location where condensed water
dripping out of the system could cause a hazard, such as above highvoltage power supplies.
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Chapter 7 _____________________________________________________ Measuring the Dewpoint
CHAPTER 7
MEASURING THE DEWPOINT
This chapter provides instructions on how to conduct dewpoint
measurements with the DM500, and contains additional information
about the moisture phases.
Dewpoint Measurement with DM500
Do not assemble the instrument in a location where condensed water
dripping out of the system could cause a hazard, like above highvoltage power supplies.
1. After the installation procedures, turn the power on by pressing
the power ON/OFF button .
2. Let the system warm up for at least 1 minute before starting the
measurements.
3. When the device is ready for use, the following display appears:
Display before activating the
measurement mode
4. Select the water or air cooling method. Press the soft key ►
Measu settings, select by using arrow button Cooling method. Select
WATER or AIR . See page 38, Selecting the cooling method.
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User's Guide ______________________________________________________________________
5. To achieve the optimum measuring results, clean the sensor and
determine the clean sensor value before the first measurements,
see page 65.
6. Start measurement by pressing
7. Wait until yellow led turns to green in the DMP501 dewpoint
sensing unit front panel. The symbol disappears from the
display and the error limit value appears on the upper right
corner of the display. The measuring cycle is now balanced.
You can follow the stabilization from the graphic trend.
Error limit value
↓
8. Droplet symbol 6 on the upper left corner of the display
indicates the presence of dew on the sensor.
If the condensation on the sensor freezes the droplet changes to a
snowflake symbol 7. If the sensor has both dew and frost on the
surface, both 6 and 7 symbols are displayed. The moment of
instability is indicated both by blinking 6 and 7 symbols as well as by
increased error limit value. The instability period usually lasts less
than 10 minutes until the condensation is frozen. Thus, the user need
not keep track of the moisture phase in order to obtain reliable
measurement results in the temperature range where either dew or
frost or both can exist on the sensor (typically 0 ºC...-30 ºC)
START/STOP.
Measurement mode display
More About the Moisture Phases 67
The system detects the phase of the moisture on the sensor
automatically and uses this phase data when converting measured
sensor temperature to the user selected unit. For example, if the user
wishes to output dewpoint, not frostpoint, the system uses the
measured sensor temperature as dewpoint temperature as long as the
moisture phase remains liquid (6 symbol in the display). If the
dewpoint is low, the sensor may freeze. The system detects the
moment of freezing and thereafter considers the sensor temperature to
be the frostpoint temperature. This frostpoint temperature is
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Chapter 7 _____________________________________________________ Measuring the Dewpoint
automatically converted to a corresponding dewpoint temperature,
which is then displayed to the user. The symbol on the display
changes to 7 after the freezing is complete.
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Chapter 8 ________________________________________________________ Displays and Menus
CHAPTER 8
DISPLAYS AND MENUS
This chapter describes the user interface.
Main View (In Measuring Mode)
Selected quantities:
Displayed in gray =
value is set or inactive
Displayed in black =
value is measured
Error limit
1 2 3 4 5 ↓
Starts/stops measuring
Shortcut to Measuring
settings
Shortcut to Self diagnosticsmenu
Shows the graphical trend
Figure 16 Main View Display
The following numbers refer to Figure 16 above:
1 = Symbol that indicates if the measuring status: active (OK),
stopped (STOP), wait (
2 = Symbol which indicates the form of the moisture on the
sensor 6 water, 7 frost.
3=
4 = Symbol which indicates that optional pump for the sampling
5 = Shows that the alarming condition is valid.
Symbol which indicates the cooling method, air, water
line is on. If this symbol is not shown, the pump is off.
).
-menu
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User's Guide ______________________________________________________________________
Error limit: The 2σ deviation of the measured sensor temperatures.
Appears when the system is balanced and statistical filtering activated.
During an unstable intermediate moisture phase indicated by blinking
6 and 7 symbols, error limit value is higher than in stabilized state.
Preset value(s): All the preset values are shown in the header if they
are not selected for the display.
Values shown in the display in black color are active measured values.
Temperature, flow, or pressure values in gray color are preset, not
measured. T
are gray showing the sensor temperature when the
d/Td/f
measurement is in stop mode. Other humidity quantities are not shown
in stop mode.
Graphical Display
Figure 17 DM500 Graphical Display
Graphical display shows you the measurements in a form of curve.
From the curve you can examine the data trend and history of the last
few hours.
1. In main view, press
MENU, select ►Display-Graphic trend).
Graphic trend or (alternatively open the
2. Graphical display opens. For more information, select the screen
Graphical trend.
3. Press
MAIN VIEW to return to the main view.
More information on graphic trend on page 55.
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Chapter 8 ________________________________________________________ Displays and Menus
Menus and Navigation
In the menus you can change settings and select the functions.
1. Open the main menu by pressing any of the buttons.
2. Move in the menus by using buttons.
3. Select the item with button.
4. Press to return to the earlier level.
5. Press EXIT to return you back to the main view.
Figure 18 DM500 Menus and Displays
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Chapter 9 _____________________________________________________________Basic Settings
CHAPTER 9
BASIC SETTINGS
This chapter provides instructions on how to make the basic settings.
User Interface
Setting the Language
1. Open the MENU: press .
2. Select ►Settings, press .
3. Select ►User Interface, press .
4. Select L anguage, press SET.
5. Select the language (English/ German/ French/ Finnish/
Spanish) and press SELECT.
6. Press
EXIT to return to the main view.
Changing the Shortcut Keys
As a default, the four shortcut keys refer to the functions Start/Stop,
Measurement settings, Self diagnostics and Graphic trend. If needed, a
►
shortcut for the functions can be changed according to your needs.
1. Open the
MENU: press .
2. Select ►
3. Select ►
4. Select Program shortcut keys, press START.
VAISALA _______________________________________________________________________ 49
Settings, press .
User Interface, press .
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User's Guide ______________________________________________________________________
5. Press the shortcut key you want to change, for example
►
Measurement settings.
6. Select the new shortcut function by using arrow buttons, press
SELECT. Answer YES to confirm your selection, otherwise answer
NO and continue from item 4.
7. Press
EXIT to return to the main view.
Key Click ON/OFF
You can turn the button pressing sound effect on or off.
1. Open the MENU: press .
2. Select ►Settings, press .
3. Select ►User interface, press .
4. To turn on or off sound effect while pressing the buttons, select
Key Click and press ON/OFF.
5. Press EXIT to return to the main view.
Setting Date and Time
Open the MENU: press .
6. Select Setting, press .
7. Select Date and time, press .
8. The default date presentation format is year-month-day, for
example 2001-11-01. To change the date, select
SET. Change the date by using arrow buttons or numerical
Date and press
buttons. To confirm the date, press OK. If you want to change
the format, select
format month/day/year or date.month.year), press
Date format, press SET. Select the other date
SELECT.
9. The default time presentation format is 24-hour clock. To
change the time, select Time and press SET. Change the time by
using arrow buttons and numerical buttons. To confirm the time,
press
OK. If you want to change the format, select 12-hour clock,
press ON/OFF.
10. Press
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EXIT.
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Chapter 9 _____________________________________________________________Basic Settings
Device Information
The basic information about the DM500 is found as follows:
1. Open the MENU: press .
2. Select ►Settings, press .
3. Select Device information, press SHOW.
4. The display gives the basic information on the device. Press
OK, MORE to get more information and EXIT to return to the
main view.
Figure 19 DMI500 User Interface Unit Information
Figure 20 DMP501 Dewpoint Sensing Unit Information
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Reverting Factory Settings
Factory settings can be reverted to clear all changed settings and data
memory. Reverting factory settings does not affect sensing unit
calibration.
1. Open the MENU: press .
2. Select ►Settings, press .
3. Select Factory settings, press
the reverting.
4. The device resets automatically.
REVERT. Press YES to confirm
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Chapter 10 __________________________________________________________ Display Settings
CHAPTER 10
DISPLAY SETTINGS
This chapter describes the display settings.
Display Backlight
The display backlight is automatically on when the device is turned
on. After 10 hours use, the backlight turns off. When pressing any
button, the light turns on again.
Selecting the Quantities and Units
The following quantities and units can be chosen to the display:
Parameter Unit
T
, T
d/f
2
2
12
12
12
2
2
12
1
1
2
3
1
If sampling from process, parameter is relevant only if the optional
temperature sensor is used to measure real temperature of the process
gas (or if the actual T value is set manually).
d
Pw (water vapor partial pressure) mbar
H2O (water content in ppmv) ppm
RH (relative humidity) %RH
T
wet-bulb temperature) ºC or ºF
w (
a (absolute humidity) g/m3, gr/ft
a
(absolute humidity in NTP conditions) g/m3, gr/ft
NTP
x (mixing ratio) g/kg, gr/lb
h (enthalpy) kJ/kg, Btu/lb
ºT (difference of T and T
)ºC or ºF
d/f
T (temperature) ºC or ºF
P (pressure) bar, hPa, psi, torr
Flow slpm, scfh
ºC or ºF
v
3
3
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2
If sampling from process, parameter is relevant only if the optional
pressure sensor is used.(or if the actual P value is set manually)
3
If sampling from process, parameter is relevant only if the optional
flow sensor is used (or if the actual Flow value is set manually).
More about the difference between Td/f and Td on page 128.
To select the displayed quantities:
1. Open the
2. Select ►Display, press .
3. Select ►Quantities and units, press
4. Select the quantity you want by using the arrow buttons, press
SELECT.
5. Select and change similarly the other quantities and units. Four
quantities can be chosen for the display.
6. Press EXIT to return to the main view.
NOTE
When changing the unit via the serial line, the display unit changes
simultaneously, see command UNIT.
Hold/Save Display
MENU; press .
Hold/Save function enables you to freeze a certain display reading.
This reading can be saved into the memory as a single data point.
1. Open
MENU: press .
2. Select ►Display, press
3. Select Hold/Save display, press HOLD to freeze the display. The
frozen measurement data is displayed.
4. Press SAVE to save the reading or EXIT to return to the main
view.
5. You can save several readings with
HOLD-SAVE function. All the
individually saved readings are stored in a same file marked
with and a start date.
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Chapter 10 __________________________________________________________ Display Settings
6. To view the saved readings, open the menu, select
Recording/Viewing, press , select View recorded data, press .
7. Select the file marked with
, press SHOW. Now you can see
the firstly saved data reading on the display numerically and
pointed out in graphics with a vertical line (the curve shows all
the individual data points). Press
to see the next data point
numerically etc. The saving times of individual data points are
shown in the first row of the display, after the date.
8. Press NEXT to see the other parameters (temperature, pressure
and flow).
9. Press INFO to see the statistics of the saved data points.
10. Press OPTIONS to set the following graph options:
Show value: Select YES to have the data points shown
numerically. Select NO to hide the numerical value.
Hide function keys: Select YES to hide the function keys shown in
the right side of the display. Select NO to have the function
keys shown.
Automatic scale: Select YES to have the y-axis scaled
automatically. Select NO to have the y-axis scaled manually. To
set the scaling manually, select with the arrow button the Min and
Max values and change the values by using the numerical
buttons. If you set manually impossible values (for example
min > max), the automatic scaling is forced to the on state.
11. Press BACK and EXIT to return to the main view.
All the individual
Hold/Save data points are saved in the same file until
the power is switched off. When switching on again and saving data,
the data points are saved in a different data file.
Graphic Trend
Graphic trend shows you the data curve from the time turning on the
device.
1. Open MENU: press .
2. Select ►Display, press
3. Select Graphic trend, press SHOW.
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4. Press NEXT to see the graphic trend of the other parameters.
5. Press
6. Press
Show value: Select YES to have the data shown numerically.
INFO to see the statistics of the saved data.
OPTIONS to set the following graph options
Select NO to hide the numerical value.
Hide function keys: Select YES to hide the function keys shown in
the right side of the display. Select
NO to have the function
keys shown.
Automatic scale: Select YES to have the y-axis scaled
automatically. Select NO to have the y-axis scaled manually.
To set the scaling manually, select with the arrow button the
and Max values and change the values by using the numerical
buttons. If you set manually impossible values (for example
min > max ), the automatic scaling is forced to the on state.
7. To zoom in the curve, press the arrow button . To zoom out,
press the button . To select the individual data points from the
curve, press either of the buttons .
8. Press MAIN VIEW to return to the main view.
Min
Contrast Adjustment
You can change the contrast of the LCD display using the Contrast
adjustment
.
1. Open MENU: press .
2. Select ►
3. Select
Display, press .
Contrast adjustment, press START.
4. To increase the contrast, press
5. To decrease the contrast, press LIGHT.
6. Press
OK and EXIT to return to the main view.
Alarm Sound
DM500 alarms by beeping and blinking the display. You can select
the alarm quantity and set the alerting set points. The alarm function
can be enabled also on the basis of the measurement status. If there are
no set points selected, measurement status controls the alarm.
DARK.
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Chapter 10 __________________________________________________________ Display Settings
1. Open MENU: press .
2. Select ►Display, press .
3. Select
press
Quantity, press SET , select the quantity for the alarm and
SELECT.
4. Select Alert above, press SET. (In case you want to delete the
setpoint, press DELETE and go to item 6).
5. Press CLEAR and give the value by using numerical buttons.
Press
6. Select
OK.
Alert below, press SET. (In case you want to delete the
setpoint, press DELETE and go to item 8).
7. Press CLEAR and give the value by using numerical buttons.
Press OK.
8. Select ENABLED WHEN, press SELECT. Now you can select the
measurement status that activates the alarm.
STOP: alarm is enabled when dewpoint measuring status is STOP.
ERR: alarm is enabled when dewpoint measuring status is ERR.
OK: alarm is enabled when dewpoint measuring status is OK
WAIT: alarm is enabled when dewpoint measuring status is WAIT
All the modes selected: alarming is not dependent on any
measurement status (only on numeric set points).
None of the modes selected (never): alarming is disabled.
You can select any combination of the measurement status to control
the alarm.
9. Press
OK and EXIT to return to the main view.
Alarming
The display is beeping and blinking and the note sign message is
shown in the display. Mute the alarming by pressing
MUTE and OK.
If the alarming condition is still valid a small note sign remains in the
header of the display. The note sign disappears when the alarming
condition is not valid anymore.
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Chapter 11 _____________________________________________________ Measurement Settings
CHAPTER 11
MEASUREMENT SETTINGS
This chapter provides you with information about the measurement
settings.
Automatic Frost Detection
The automatic dew/frost sensing procedure senses if the condensation
on the sensor is water (dew) or ice (frost). If the sensing is turned off,
the T
sensor state. Then the other water content quantities are disabled. If
the sensing is on (default), the T
0 ºC/32 ºF is always frostpoint.
1. Open MENU: press .
2. Select ►Measuring, press
3. Select ►Measurement settings, press .
4. Select
5. To enable the sensing, press ON.
6. To disable the sensing, press OFF.
7. Press
value can be either dewpoint or frostpoint, depending on the
d/f
Autom.frost detection.
EXIT to return to the main view.
value below temperature of
d/f
NOTE
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Cleanliness of the sensor is essential for the proper operation of frost
detection.
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User's Guide ______________________________________________________________________
Forced Freezing
In some measurement conditions there may be formation of a two
phase system, ice-dew, on the sensor. This situation is dynamic and
the time needed to reach an equilibrium may be rather long. To avoid
an unstable phase transition, the DM500 has a function for generating
a stable layer of frost on the sensor right from the beginning of the
measurement.
When turned on, the forced freezing procedure is automatically
enabled when measurement is started. However, the forced freezing
procedure may also be turned off by the user, if so desired.
The automatic forced freezing procedure recognizes the temperature at
which condensation begins to form on the sensor surface. The control
of the forced freezing procedure is based on this temperature, and
therefore the dewpoint of the measured gas should be stable during the
freezing procedure. If forced freezing is enabled and the frostpoint is
ca. -6...-30 ºC, the procedure will freeze the sensor cold enough for the
condensation to form a stable layer of frost. Use of forced freezing
may lengthen the measurement start-up time.
If forced freezing is disabled by the user, in certain conditions
formation of an unstable phase system on the sensor is possible.
1. Open MENU: press .
2. Select ►Measuring, press
3. Select ►Measurement settings, press .
4. Select Forced freezing.
5. To enable the function, press ON.
6. To disable the function, press OFF.
7. Press
EXIT to return to the main view.
Cooling Method Air/Water
Select the cooling method air ( ) or water ( ) by using this function.
Water cooling is recommended when measuring dewpoints below
-50 ºC (-58 ºF) or above +40 ºC (104 ºF).
This selection optimizes the operation of thermoelectric coolers.
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Chapter 11 _____________________________________________________ Measurement Settings
NOTE
Select the water cooling only if the water is actually supplied to the
sensing unit. Otherwise the sensing unit can be overheated
To select the cooling method:
1. Open MENU: press .
2. Select ►Measuring, press .
3. Select ►Measurement settings, press .
4. Select
5. To select air cooling, press AIR.
6. To select water cooling, press
7. Press EXIT to return to the main view.
More information about selecting the cooling method on page 38.
Statistical Filtering
Cooling method.
WATER.
The statistical filtering is on as default. When the filtering is on, the
dewpoint reading is changing in steps and the statistical uncertainty
value is calculated for each reading and the statistical error limit is
shown in the display. If the filtering is turned off, the reading shows
the trend of the sensor temperature variation in real time. Thus,
changes in humidity can be seen more rapidly but the error limit is not
shown in a display.
1. Open
2. Select ►
3. Select ►
4. Select
5. Press
MENU: press .
Measuring, press .
Measurement settings, press .
Statistical filtering, press OFF.
EXIT to return to the main view.
The statistical filtering can also be turned on/off by using serial
command ANAL, see serial commands.
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Response Speed
You can set the response speed to stable, normal (default) or fast. If
fast transients in the dewpoint prevent the system from reaching
balance, the signal can be stabilized by selecting the Stable response
speed. Fastest response time is achieved by setting the speed to Fast
but this may increase the noise in the dewpoint measurement. As a
rule of thumb, always use the fastest setting that gives stable readings!
1. Open MENU: press .
2. Select ►Measuring, press .
3. Select ►
4. Select
5. Select one of the following options:
6. Press EXIT to return to the main view.
Pump ON/OFF
1. Open MENU: press .
2. Select ►
3. Select ►Measurement settings, press .
4. Select Pump, press ON/OFF.
Measurement settings, press .
Response, press SET.
Stable: Press SELECT to have the slowest response speed.
Normal: Press SELECT to have normal response speed.
Fast: Press SELECT to have fast response speed.
Measuring, press .
5. Press EXIT to return to the main view.
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Chapter 11 _____________________________________________________ Measurement Settings
Transient Recovery Time
The transient recovery time is the time the sensor waits before starting
the fast recovery cycle after rapid dewpoint change. If there are large,
rapid step changes in humidity level the shorter transient recovery
times are recommended. If the changes are slow (like typically at low
dewpoints), the longer transient recovery times are recommended.
Selecting the Off option turns the transient recovery time function off,
meaning that after rapid dewpoint change the fast recovery cycle will
not be initiated.
NOTE
It is not recommended to turn Off the transient recovery time function.
If there are large, rapid dewpoint changes and the transient recovery
time function is off, the response time may be hours.
1. Open MENU: press .
2. Select ►Measuring, press .
3. Select ►Measurement settings, press .
4. Select Transient recov., press SET.
5. Select one of the following options, press SELECT.
20 s, 60 s, 2 min (default), 5 min, 15 min, Off.
6. Press EXIT to return to the main view.
Setting the Temperature, Pressure, and Flow
Values
In case the device does not have the optional temperature, pressure
and flow sensors, the fixed manually fed values (e.g. for calculations)
are given as follows:
1. Open
2. Select ►
3. Select ►Process variables, press .
4. Select the parameter you want to change by using the arrow
5. Press CLEAR to clear the old value.
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MENU: press .
Measuring, press .
buttons.
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6. Set the new value by using numerical buttons.
7. Press
8. Press
The
Process variables selection menu is only available for those
OK to confirm the settings.
EXIT to return to the main view.
parameters that are set, not measured.
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Chapter 12 ___________________________________________________ Self Diagnostics Settings
CHAPTER 12
SELF DIAGNOSTICS SETTINGS
This chapter describes the self diagnostic functions settings. The
DM500 goes through a self diagnostics procedure when the power is
switched on. If an error is found, the error display tells about it.
However, there are some self diagnostics operations that the user can
set, such as Salt detection, Sensor circuit check and Cooling capacity
test.
Salt Detection
During the salt detection function the wet sensor impedance is
detected to see if there is hygroscopic contamination on the sensor.
The clean sensor value (salt detection limit) is checked as reference.
Therefore, please clean the sensor always before determining the clean
sensor value. The clean sensor value is preset at the factory, but redetermination by the user is recommended for optimum results.
The automatic salt detection is off as a default. You can turn it on by
setting the interval and salt detection limit. The manual salt detection
can be done to check if the sensor is clean.
Salt detection works only when there is dew on the sensor. Frostpoint
measurement is very little affected by hygroscopic contaminants, due
to the limited mobility of the ions. Consequently, a typical effect of
hygroscopic contamination on measurements is a large positive offset
that appears after the moisture phase on the sensor changes from frost
to dew.
The salt detection, as well as the clean sensor value determination
require a gas flow with dewpoint above 0º C through the sensing unit.
Lower dewpoints can also be used as long as the moisture phase
remains liquid.
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If the salt detection sees salt on the sensor (message on the display),
please clean the sensor carefully, see page 113. The salt warning
message is shown when the measured value decreases below 80 % of
the salt detection limit. It is not recommended to use serial commands
during the salt detection. Salt detection interrupts the dewpoint
measurement for approximately one minute.
The salt detection function is enabled as follows:
1. Open
MENU: press .
2. Select ►Measuring, press .
3. Select ►Self diagnostics, press .
4. Select ►
5. To enable the automatic sensing, select
SET and give the salt sensing interval (1...99 h) by using the
Salt detection.
Autodetect interval, press
numeric buttons.
6. Press OK.
7. Carry out this step only if you want to determine the clean
sensor value after cleaning.
Select Clean sensor value, press DETERMINE. In this stage, the
system measures the salt detection limit (clean reference). To
disable the automatic sensing, press OFF.
8. To start the manual salt sensing test, select Manual salt sensing
and press START.
9. Press EXIT to return to the main view.
Sensor Circuit Check
During the sensor circuit check the sensor is heated up and the
propagation of the RF-signal through the circuit is checked. If the
system is not operating as expected the error message is shown, see
page 115, Error Messages. The sensor circuit check also re-calculates
the transmission for a dry sensor, thus performing contamination
compensation.
Sensor circuit check is performed automatically each time when the
measuring is started. During the measuring, the periodical checking is
not done (default) unless the automatic sensor circuit check is turned
on by setting the interval. In case there is a need for checking the
operation of the sensor periodically, or if automatic dry-out cycle for
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Chapter 12 ___________________________________________________ Self Diagnostics Settings
the sensor is desired, you can set the automatic checking interval
(1...99 h) as follows:
1. Open
MENU: press .
2. Select ►Measuring, press .
3. Select ►Self diagnostics, press .
4. Select
Sensor circuit chk.
5. To turn on the sensor checking circuit and set the checking
interval, press SET.
6. Set the interval (1...99 h) by using the numerical buttons.
7. Press OK to confirm the setting. Now the automatic sensor
circuit check will be done in determined intervals.
8. If needed to turn off the checking operation, press OFF.
9. Press EXIT to return to the main view.
Cooling Capacity Test
In the cooling capacity test the sensor is cooled to the lowest possible
temperature. The measurement mode must be stopped during the
cooling capacity test.
1. Open MENU: press .
2. Select ►Measuring, press .
3. Select ►
Self diagnostics, press .
4. Select Cooling capacity test
5. Press START to start the test. The test may take up to 20 min.
During that time the measuring is stopped and you can follow
the actual temperature of the sensor from the display:
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The serial output command R shows frozen values. You can cancel
the testing sequence by pressing the
CANCEL.
6. When the test is completed, you see the following display:
7. Press EXIT to return to the main view.
The following factors affect the cooling capacity:
- Temperature of the environment
- Temperature of the cooling water and
- Gas flow rate of the sample.
Please, check that these settings are correct, see chapter Setting up for
Operation, page 35. The graphs on pages 27 and 29 show the lowest
achievable sensor temperatures. In addition, to obtain correct results,
the test should be started with the system at equilibrium with room
temperature.
Error History
The error history shows on the display six last shown error messages.
1. Open
2. Select ►Measuring, press .
3. Select ►
4. Select
5. Press SHOW to see the last shown error display. Press NEXT to
MENU: press .
Self diagnostics, press .
Error history.
see the earlier ones.
6. To clear the error history, press
7. Press
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EXIT to return to the main view.
CLEAR.
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Chapter 13 ___________________________________________________________Recording Data
CHAPTER 13
RECORDING DATA
This chapter provides instructions on data recording with the DM500.
Data Recording
You can record measurement data and view the recorded data on the
display.
1. Open MENU: press .
2. Select ►Recording/Viewing, press .
3. Select ►Record data, press .
4. Select Interval, press SET.
5. Set the measurement interval by selecting the interval time by
using the arrow buttons, press
Note, you can not set longer interval than the measurement
duration !
6. Set the measurement duration (5 min, 15 min, 30 min, 1 hours, 3
hours, 12 hours, 24 hours, 7 days, 30 days, memory full) by
selecting Duration, press SET. Note the maximum recording
durations are based on the measurement interval !
7. To start recording, select
progress bar
of recorded data.
is shown on the display showing the amount
Start/Stop recording, press START. The
SELECT. See the table below.
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Interval Max. recording duration
(memory full)
5 s 68 min
15 s 3 h
30 s 6 h
1 min 13 h
5 min 68 h
15 min 8 d
30 min 17 d
1 hour 34 d
3 hours 102 d
12 hours 409 d
Stopping Recording
1. Open MENU: press .
2. Select ►Recording/Viewing, press .
3. Select ►Record data, press .
4. To stop recording, select Start/Stop recording and press STOP.
5. Now you can go and see the recorded file by selecting SHOW.
Viewing Recorded Data
When viewing the recorded data, firstly choose for the main view the
quantities you want to view. Then follow the instructions below.
1. Open
2. Select ►Recording/Viewing, press .
3. Select ►
4. Select the file you want to view, press
MENU: press .
View recorded data, press .
identified according to the date and starting time of recording.
SHOW. The files are
Checking the Recording Memory Status
You can check how much there is free space for recording in the
memory.
1. Open MENU: press .
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Chapter 13 ___________________________________________________________Recording Data
2. Select ►Recording/Viewing, press .
3. Select Memory status, press SHOW to see the amount of memory
in use and the estimated free space.
4. To return to the main view, press OK and EXIT.
Deleting All Record Files
The data memory can be cleared as follows:
1. Open MENU: press .
2. Select ►Recording/Viewing, press .
3. Select Clear data memory, press CLEAR. Press YES to confirm
deletion of all recorded data files.
4. Press EXIT to return to the main view.
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Chapter 14 _________________________________________________________ Output Interfaces
CHAPTER 14
OUTPUT INTERFACES
This chapter describes the serial communication settings and outputs
of the DM500.
1
C NO NC
REL 1
6
Figure 21 DMI500 User Interface Unit Back Panel (Same as
The following numbers refer to Figure 21 above:
1 = Relay outputs (optional)
2 = Serial port (EIA-232, RS232 for Terminal/MI70-link
3 = Connection to DMP501
4 = Mains cable
5 = RS485 and LonWorks-port (optional)
6 = Analog outputs (optional)
C NO NC
REL 2
5
Figure 3)
2
4
3
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CAUTION
The dip switches behind the DMI500 MUST NOT be touched,
because the processor may be destroyed as a result of false dip switch
positions.
NOTE
Before connecting a PC to DMI500 or DMP501, make sure there is
no ground potential difference between PC and the DM500.
Serial Communication Settings
Connect the DM500 to PC by using a serial cable (provided). When
connecting EIA-232 (RS232), use the port called 'SERIAL'. When
connecting optional RS485, use the port called 'RS485/LON'. Connect
the RS485 as follows:
Table 2 4-Wire Connection
Terminal Data Line
1 R+ (input to DM500) ←
2 R- (input to DM500) ←
3 T+ (output from DM500) →
4 T- (output from DM500) →
5 Shield
Table 3 2-Wire Connection
Terminal Data Line
1 R/T+ connect the same line to
terminals 1 and 3
2 R/T- connect the same line to
terminals 2 and 4
3 R/T+ connect the same line to
terminals 1 and 3
4 R/T- connect the same line to
terminals 2 and 4
5 Shield
Select the DM500 communication mode and data transfer settings as
follows:
1. Open
MENU: press .
2. Select ►Interfaces, press .
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3. Select ►Communications, press .
4. Select Comm. mode, press SET.
5. Select one of the following mode, press SELECT:
STOP: Outputs measurements only by command. All
commands can be used.
RUN: Outputs measurements automatically in a format set by a
serial command FORM. Only serial command S can be used.
POLL: Outputs measurements only with the serial command
SEND.
MI70 Link: Sets the MI70 Link program communication
parameters. Other communication settings have no effect when
using MI70 Link software.
6. Set the polling address if needed, select Polling address, press
SET.
7. Give the address for POLL communication mode by using
numerical buttons, press OK.
8. Select Baud rate, press SET.
9. Select one of the following baud rate, press SELECT:
300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600,115200
bps
10. Select Serial format, press SET.
11. Select the data bits (7 or 8), parity (N = none, E = even,
O = odd) and stop bits (1 or 2), press SELECT.
12. Select Echo or Half duplex, press NO/YES to turn the functions
on/off.
13. To return to the main view, press
Analog Outputs (Optional)
DMI500 user interface can be equipped with three optional 4...20 mA
passive current outputs. These 2-wire channels must be powered with
12...28 VDC external power supplies (not provided). The analog
outputs are galvanically isolated from electronics but they are not
isolated from each other. Thus, you need a separate (isolated) power
supply for each monitored analog channel.
EXIT.
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The port connections are as follows:
pin 1: ch+ (+VDC supply voltage)
pin 2: ch- (-VDC supply voltage)
pin 3: test (for service use only)
pin 4: shield
When using 12V loop voltage, the resistance must be less than 90
ohms. An approximate can be calculated by following formula:
Rmax = (V
- 10V)/20mA
loop
You can scale the output to any output range. It is recommended to
have the scaling within the measuring range to get accurate
measurements.
1. Connect the analog output signal cable connector to the
connector, see Figure 21 on page 73.
2. Open MENU: press .
3. Select ►Interfaces, press .
4. Select ►Analog outputs, press .
5. Select ►Output 1, press .
6. Select Quantity, press SET , select the quantity for the analog
output and press SELECT.
7. Select Scale 4 mA, press SET.
8. Press CLEAR and give the lowest value (value represented by 4
mA current) by using numerical buttons. Press OK.
9. Select Scale ...20 mA, press SET.
10. Press
CLEAR and give the highest value (value represented by
20 mA current) by using numerical buttons. Press OK.
11. Select ENABLED WHEN, press SELECT. Now you can select the
measurement status that activates the analog outputs.
STOP: output is enabled when dewpoint measuring status is
STOP.
ERR: output is enabled when dewpoint measuring status is
ERR.
OK: output is enabled when dewpoint measuring status is OK
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Chapter 14 _________________________________________________________ Output Interfaces
WAIT: output is enabled when dewpoint measuring status is
WAIT
All the modes selected: output activity is not dependent on any
measurement status.
None of the modes selected (never): output is not enabled
(invalid output).
You can select any combination to control the output.
12. Select
Invalid output to set the output reading when the output is
not enabled. Press SET (setting can be done also by using serial
line, see command AERR).
13. Press
CLEAR and give the invalid value by using numerical
buttons. The value of the invalid output shall be 4...20 mA.
Press
OK.
14. Press EXIT to return to the main view.
15. Set the other outputs similarly.
Analog outputs can be configured also by using the serial line (see
command ASEL).
Relay Outputs (Optional)
The DMI500 user interface can be equipped with two configurable
single pole double throw relays. The maximum voltage connected to
relay terminals is 42 V DC/60 V Peak. Select the quantity, setpoints,
and hysteresis and set the criteria for enabling the function.
1. Open MENU: press .
2. Select ►
Interfaces, press .
3. Select ►Relay outputs, press .
4. Select ►Relay 1, press .
5. Select
Quantity, press SET , select the quantity for the relay
output and press SELECT.
6. Select
Active above: xx, press SET. Set the value above which you
want the relay to be activated. Use the numeric buttons. Press
OK.
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7. Select Active below: xx, press SET. Set the value below which you
want the relay to be released. Use the numeric buttons. Press
OK.
When the measured value is in between the above and below
values, the relay is passive. When choosing lower value as
above value and higher value as below value the relay is passive
when the measured values is not between the set values. You
can set only one value or remove both setpoints by pressing
DELETE. If both setpoints are removed the state of the relay
changes on the basis of the measurement status, see further
instructions.
8. Select HYSTERESIS, press SET. Set the value by using numeric
buttons. Press OK.
Relay is activated when the measured value passes the setpoint.
As returning and passing the setpoint again relay is released
only until the value is reached the setpoint decreased/increased
by the hysteresis value.
Hysteresis function is to prevent the relay switching back and
forth when measured value is not stable near to the set point
values given.
Example: when the active above value is +20 ºC and the
hysteresis value is 2 ºC, relay changes state when the dewpoint
reaches 20 ºC. When the dewpoint decreases, relay changes state
at 18 ºC.
9. Select ENABLED WHEN, press SELECT. Now you can select the
measurement status that enables function of the relays.
10. Set the measurement status that determines when the relays are
enabled. Relay changes state on the basis of the measurement
status if there are no setpoints determined. If the setpoints are
determined the relay changes state on the basis of the setpoint
when the selected measurement status is active. Otherwise the
relay is disabled.
STOP: relay is enabled when dewpoint measuring status is
STOP
ERR: relay is enabled when dewpoint measuring status is ERR
OK: relay is enabled when dewpoint measuring status is OK.
WAIT: relay is enabled when dewpoint measuring status is
WAIT.
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All the modes selected: relay function is not dependent on any
measurement mode.
None of the modes selected (never): relay function is disabled.
You can select any combination of the measurement status.
Example: If you want to have relays working on the basis of the
STOP and ERR mode to know when the measurement data is
not valid, delete the setpoints and select enabled when: STOP
and ERR mode.
11. Press EXIT to return to the main view.
12. Set the other relay similarly.
13. You can test the relay operation with the Relay test button.
Relay is forced to change state as long as you press the Relay
test button.
Relays can be configured also by using the serial line (see command
RSEL).
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Chapter 15 _________________________________________________Calibrationd and Adjustment
CHAPTER 15
CALIBRATIOND AND ADJUSTMENT
This chapter provides you with information about the calibration and
adjustment of the DM500.
General About Calibration and Adjustments
Calibration Interval
The DMP501 dewpoint sensing unit is fully calibrated as shipped
from factory. The recommended calibration interval is one year.
However, calibration shall be done if there is a reason to believe that
device is not within the accuracy specifications.
In adjustment, the reading of DM500 is changed to correspond to the
reference value. After adjustment, the original calibration certificate
shipped with the product is not valid anymore.
Calibration Laboratory
The dewpoint calibration shall be carried out at Vaisala or in other
calibration laboratory capable to perform high accuracy dewpoint
calibrations traceable to national/international standards.
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Calibrating DM500 Equipped with a
Pump
If you have the DM500 with a pump, ensure that the sample flow rate
from the humidity generator is sufficient. See the following example:
Humidity
generator
Figure 22 Gas Flow Rate from the Humidity Generator
Making an Adjustment
DMP501 needs 4...10 dewpoint reference points within dewpoint
temperature range -80 ºC...+60 ºC for the adjustment. These dewpoint
reference points shall be traceable to appropriate standards. The
dewpoint temperature references shall cover the measurement area in
which the instrument is used.
The adjustment can be done also by using the serial commands.
Gas flow
> 3 slpm
Open outlet
(with diffusion coil)
Reference
instrument
1 splm
1 splm
DM500
If you have adjusted the device earlier, you shall clear the previous
adjustments before giving new adjustment data.
1. Open
MENU: press .
2. Select ►Settings, press .
3. Select ►Adjustments, press .
4. Select ►
5. Press
Dewpoint adjustments, press .
CLEAR and YES , OK to clear the old adjustment
data
Connect the reference gas flow to the gas inlet and measure the
readings in 4...10 points. Write down the readings in the different
reference points. Feed the reference points and corresponding readings
to the device to make the adjustment.
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Chapter 15 _________________________________________________Calibrationd and Adjustment
6. Turn the service switch 4 to ON-position (adjustment enabled),
see page 18, Figure 4, DMP501 back panel, service switches.
7. Open
8. Select ►
9. Select ►
MENU: press .
Settings, press .
Adjustments, press .
10. Select ►Dewpoint adjustments, press .
11. Press SET. Give the reference value (Ref.) by using the
numeric buttons. Then, give the measured value (Meas.). Press
OK.
12. Select with the arrow button the next reference point and press
SET.
13. Continue giving the references.
14. Make the adjustment by pressing Adjust.
15. The adjustment result is shown.
16. Press EXIT.
17. Turn the service switch 4 to OFF-position (adjustment disabled).
The system calculates a 3rd degree correction polynomial fitted to the
adjustment data.
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Chapter 16 _____________________________________________________ Serial Line Commands
CHAPTER 16
SERIAL LINE COMMANDS
The DM500 detector is operated via a serial line by using suitable
terminal software like Windows Hyper Terminal (see also MI70-link).
The serial output interface is RS232.Connect the RS232 cable to the
connector on the back panel of the DMI500 user interface unit. The
serial cable can also be connected to the back panel of the DMP501
sensing unit. This port, however, has a limited command set and fixed
format (9600/8/1/none), and connecting to this port may increase the
susceptibility to electromagnetic interference.
The notation '<cr>' used in this manual in conjunction with the serial
commands stands for pressing the 'carriage return' (ENTER) key on
your personal computer keyboard.
Serial Commands
Output commands
R* Continuous output
S* Stopping the continuous output
ADDR Setting the device address
SEND* Outputting one single reading
INTV* Setting the output interval
FORM Defining the output format
Operational commands
START* Starting the measurement
STOP* Stopping the measurement
PUMP* Starting/Stopping the optional sample gas pump
HEAT* Starting/Stopping the optional heater
SALT* Enables/disables the salt contamination detection
SCAL* Starts the salt detection limit determination cycle
PTEST* Starts the cooling capacity test
ANAL* Starting/Stopping the statistical filtering
FFROST* Enables/disables the automatic forced freezing procedure
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Setting commands
SERI Setting the serial communication parameters
UNIT Setting the units
TIME Setting the date and time
RSEL Setting the relays
ASEL Setting and scaling the analog outputs
AERR Setting the invalid output value for the analog channel
COOLER* Setting the cooling method status
FLOW* Setting the flow value
XFLOW* Setting the flow value temporarily
PRES* Setting the pressure
XPRES* Setting the pressure value temporarily
TP* Setting the temperature
XTP* Setting the temperature value temporarily
Adjustment commands
CDP* Adjusting the dewpoint temperature (in 4...10 points)
CTP* Adjusting the temperature (in 2 points)
FCAL* Adjusting the flow meter (in 1 point)
PCAL* Adjusting the pressure sensor (in 2 points)
Others
? Outputting the device settings
?? Outputting the device settings in POLL-state
DEL Deleting the data files
DIR Outputting list of data files
ECHO Setting the echo ON/OFF
ERRS Outputting the error messages
HELP Outputting the commands
INIE* Returning the factory settings
SMODE Selecting the operation mode
OPEN Opening the line in poll mode
CLOSE Closing the line in poll mode
PLAY Outputting the data file or history memory
SCC* Sensor circuit check
SSC* Sensor status check
SNUM* Outputting the serial numbers of DM500
VERS* Outputting the program name and version
*when serial cable is connected to the DMP501 service port, only the commands marked with * can be used.
Command syntax and output may be different in direct connection to DMP501 sensing unit.
Output Commands (DMI500)
R Continuous Output
Syntax: R<cr>
Outputting measured values continuously. You can modify the form
of the output with the command FORM (see page 88). The resulting
interval can be set with the command INTV (see page 87). The
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Chapter 16 _____________________________________________________ Serial Line Commands
command R does not change the default operation mode set with the
command SMODE.
Example:
>r
0.000 'C 0.00 'C 0.00 hPa 0.00
slpm
0.000 'C 0.00 'C 0.00 hPa 0.00
slpm
S Stopping the Continuous Output
Syntax: S<cr>
Type S to stop outputting.
ADDR Setting the Device Address
Syntax: ADDR xx<cr>
where
xx = 0...99 (address)
The address is used in POLL mode when more than one device is
connected to one serial line.
SEND Outputting One Single Reading
Syntax: SEND x<cr>
where
x = device address (0...99) in POLL state
INTV Setting the Output Interval
Syntax: INTV xxx yyy<cr>
where
xxx = output interval
yyy = unit (s, min, h)
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Example:
>intv 1 min
Output interval: 1 MIN
>
FORM Defining the Output Format
Syntax: FORM [amount of decimals] [quantity] [u]
[status] [date][time] [addr]<cr>
With the FORM command you can determine the output form of
commands R and SEND. The following output fields can be defined
after the command FORM:
The fields can be given in any order, except the unit field U, that can
be given only after a quantity or after an error limit value. You can
give only one field or several fields and write the field descriptions
either in capital or small letters. Leave a space between the fields. The
maximum amount of characters in the command is 80.
BASIC FIELDS
[amount of decimals]
Type number of digits before and after the decimal point.
As an example: giving 2.1 before the RH quantity outputs a
reading with two digits before the point and one after the
point, as follows: 80.1. You can define different amount of
decimals before every quantity, if needed.
Type 0.0 to return the default setting
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[quantity]
Type one or several of the following quantities: TD/ TDF/
H2O/PW/RH/TW/A/ANTP/X/H/DT/T/P/FLOW/+TDF/
+TD/+PW
TD = dewpoint temperature
TDF = dewpoint/frostpoint temperature
H2O = humid air volume/dry air volume
PW = water vapour partial pressure
RH =relative humidity
TW =wet-bulb temperature
A = absolute humidity
A = absolute humidity in NTP conditions
X = mixing ratio
H = enthalpy
DT = difference of T and Td/f
T = temperature
P = pressure
FLOW = sample gas flow rate
+TDF = error limit value
+TD= error limit value
+PW = error limit value
[u]
[u1...u9]
[status]
[date]
[time]
[addr]
Type U to show a unit text after a quantity field. By typing
U1 results unit text with only one letter, U9 results space-
padded nine letters text. If needed, change the unit by using
the separate command UNIT (or by using the display
menu). This field shall be defined only after quantity field.
Type STATUS to insert the state of a dewpoint
measurement system.
The state can be one of the following: STOP (water content
measurement not operating, OK (normal operation), WAIT,
ERR (error in measurement).
Type DATE to have a date. The date is shown in form of:
yyyy-mm-dd.
Type TIME to have a time shown. The time is shown in
form of: hh:mm:ss.
Type ADDR to have the device address (set with the
ADDR command).
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OUTPUT MODIFICATION FIELDS
[text field]
[/]
[ASCII character]
[line feed]
[carriage return]
[space]
[horizontal tabulation]
If you have problems in typing \ (backslash) character, you can use #
instead of it.
Use \\ for literal backslash and ## for literal hash.
Type the text you want inside the quotation marks "text".
Type / to return the factory setting of FORM command.
Only alone, without any other specifiers.
Type \xxx where xxx is a three digit decimal number of the
character, for example \035 outputs the # character.
Type \n
Type \r
Type " " (Note! Leave a space in between the quotation
marks)
Type \t
Examples:
1. Output needed: Dewpoint/Frostpoint temperature with a unit
label by using three digits before and after the point. The error
value shown after the reading. Carriage return and line feed in
the end.
>form "Tdf=" 3.3 tdf U +tdf U \r \n
"Tdf=" 3.3 Tdf U +Tdf U \r \n
>send
Tdf= 0.383'C 0.087'C
>
2. Output needed: Dewpoint/Frostpoint temperature and the error
with a unit label. Time and status to be shown. The fields are
separated with horizontal tabulation. Carriage return and line
feed in the end.
>form "Tdf="3.3 tdf u \t +tdf u \t time \t status
\r \n
"Tdf=" 3.3 Tdf U \t +Tdf U \t TIME \t STATUS \r \n
>send
Tdf= 0.860'C 0.106'C 15:30:26 OK
>
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3. Output needed: Relative humidity and pressure to be shown with
a unit. The fields are separated with " " marks. Carriage return
and line feed in the end.
>form 2.1 rh " " u " " 2.4 p " " u \r \n
2.1 RH " " U " " 2.4 P " " U \r \n
>send
23.0 % 1.0164 bar
Operational Commands
START Starting the Measurement
Syntax: START<cr>
Starts the dewpoint measurement and activates the cooling system.
STOP Stopping the Measurement
Syntax: STOP<cr>
Stops the dewpoint measurement and disables the cooling system.
PUMP Starting/Stopping the Optional Sample Gas
Pump
Syntax: PUMP ON/OFF<cr>
Example:
>pump
Pump : OFF
>
>pump on
Pump : ON
>
>pump off
Pump : OFF
>
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HEAT Starting/Stopping the Optional Heater
Syntax: HEAT ON/OFF<cr>
Example:
>heat
Heat : OFF
>
>heat on
Heat : ON
>
>heat off
Heat : OFF
>
SALT Enables/Disables the Salt Contamination
Detection
Syntax: SALT ON/OFF [interval]<cr>
Default: SALT ON
Example:
>salt
Salt sensing : OFF 24
>
Salt sensing is off.
>salt on
Salt sensing : ON 24
>
Salt sensing is on and detection interval is 24 h.
>salt 30
Salt sensing : ON 30 <cr><lf>
>
Salt sensing is on and detection interval is 30 h.
>salt on 24
Salt sensing : ON 24
>
Salt sensing is on and detection interval is 24 h.
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SCAL Starts the Salt Detection Limit Determination
Cycle
Syntax: SCAL<cr>
The determination of the salt detection limit can take several minutes.
Please also see page 65 for more information about salt detecting.
Example:
>scal
Salt limit : 0.36280
>
PTEST Starts the Cooling Capacity Test
Syntax: PTEST<cr>
During the test device reports the sensor temperature. When the test is
completed, the lowest achievable stable sensor temperature (in current
ambient conditions) is reported.
Example:
>ptest<cr>
-12.34 'C<cr>
-22.45 'C<cr>
-31.32 'C<cr>
-35.44 'C
...<cr>
-39.34 'C<cr>
Cool. capacity: -39.12 'C<cr>
>
Typing s<cr>
interrupts the test.
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ANAL Starts/Stops the Statistical Filtering
Syntax: ANAL ON/OFF<cr>
Type command ANAL ON to turn off the statistical filtering.
Command ANAL OFF turns on the statistical filtering. See section
Statistical Filtering on page 61 for more information.
Example:
>anal on
Analog mode ???: ON
>anal off
Analog mode ???: OFF
>
FFROST Enabled/Disables the Automatic Forced
Freezing Procedure
Syntax: FFROST ON/OFF<cr>
Default: FFROST ON
Example:
>ffrost
Forced freezing: ON
Forced freezing is on.
>ffrost off
Forced freezing: OFF
Forced freezing is off.
>ffrost on
Forced freezing: ON
Forced freezing is on.
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Setting Commands
SERI Setting the Serial Communication
Parameters
Syntax: SERI [baud] [parity] [bits] [stops]
[duplex]<cr>
where
[baud] = 300/600/1200/2400/4800/9600/19200/38400/57600/1
15200
[parity] = N (none)/E (even)/O (odd)
[bits] = 7 (7 bits)/ 8 (8 bits)
[stops] = 1 (1 stop bit)/2 (2 stop bits)
[duplex] = H(half-duplex)/F (full-duplex)
The current settings are output if you give the command without the
parameter fields. Factory default: 9600/8/none/1.
The fields can be given in any order. The new settings are valid
immediately after the change. If you choose a half-duplex mode, the
echo turns automatically into OFF-position.
>seri 19200 n 8 1 f
19200 N 8 1 FDX
>
UNIT Setting the Units
Syntax: UNIT [x]<cr>
where
x = unit C or F (dewpoint, temperature, wet-bulb temperature),
g/m3 or gr/ft3 (absolute humidity), g/kg or gr/lb (mixing
ratio), kJ/kg or btu/lb (enthalpy), hPa or torr or psi or bar
(pressure), slpm or scfh (sample flow).
x=m (metric)or n (non-metric)
The unit is set by typing the desired unit(s) after the command UNIT.
All the units change form metric to non-metric (or other way round)
by typing UNIT m or UNIT n. The display units change
simultaneously.
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NOTE
When you want to have both metric and non-metric temperature units
(C/F) for different quantities, select the units with keypad. The serial
command UNIT changes all temperature units either to metric or
non-metric.
Examples:
>unit ?
Output units : 'C g/m3 gr/lb kJ/kg bar slpm
Selecting non-metric units
>unit n
Output units : 'F gr/ft3 gr/lb Btu/lb psi scfh
Changing the pressure unit
>unit bar
Output units : 'F gr/ft3 gr/lb Btu/lb bar scfh
TIME Setting the Date and Time
Syntax: TIME [date time]<cr>
where
date = yyyy-mm-dd (24 hour clock)
time = hh:mm:ss
Example:
>time
Current time: 2000-01-01 02:55:17
Enter new date (yyyy-mm-dd): 2001-10-05
Enter new time (hh:mm:ss): 12:07:00
RSEL Setting the Relays
Syntax: RSEL [q1 q2]<cr>
where
q1 = quantity for the relay 1
q2 = quantity for the relay 2
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Select the quantity, setpoints and hysteresis and set the criteria for
enabling the function. See more about the relays from page 77.
Use the following quantity abbreviations:
TDF/TD/H2O/RH/PW/TW/A/ANTP/X/H/DT/T/P/FLOW/+TDF/
+TD/+PW
Enabling criteria keywords:
OFF relay is never enabled (inactive)
STOP relay is enabled when dewpoint measuring status is STOP
ERR relay is enabled when dewpoint measuring status is ERR
OK relay is enabled when dewpoint measuring status is OK
WAIT relay is enabled when dewpoint measuring status is WAIT
ON relay is always enabled
Any combination of status STOP, ERR, OK and WAIT can be chosen.
Keywords OFF and ON can be used only alone.
Example:
>rsel tdf t
Re1 Tdf above : 20 'C ? 0
Re1 Tdf below : -20 'C ? -20
Re1 Tdf hyst : 2 'C ? 2
Re1 enable: ERR ? wait ok
Re2 T above : 30 'C ? 30
Re2 T below : 20 'C ? -40
Re2 T hyst : 1 'C ? 3
Re2 enable: ON ? wait ok
ASEL Setting the Analog Outputs
Syntax: ASEL [x y z]<cr>
where
x = quantity for the channel 1
y = quantity for the channel 2
z = quantity for the channel 3
Select the quantity and scaling and set the criteria for enabling the
function. See more about the analog outputs from page 75.
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Use the following quantity abbreviations:
TDF/TD/H2O/RH/PW/TW/A/ANTP/X/H/DT/T/P/FLOW/+TDF/
+TD/+PW
Enabling criteria keywords:
OFF relay is never enabled (inactive)
STOP relay is enabled when dewpoint measuring status is STOP
ERR relay is enabled when dewpoint measuring status is ERR
OK relay is enabled when dewpoint measuring status is OK
WAIT relay is enabled when dewpoint measuring status is WAIT
ON relay is always enabled
Any combination of status STOP, ERR, OK and WAIT can be chosen.
Keywords OFF and ON can be used only alone.
Example:
>asel td rh t
Ch1 Td lo : 100 'C ? -80
Ch1 Td hi : 20 'C ? 20
Ch1 enable: WAIT OK ? wait ok
Ch2 RH lo : -100 % ? 0
Ch2 RH hi : 100 % ? 100
Ch2 enable: ON ? ok wait
Ch3 T lo : 0 'C ? -40
Ch3 T hi : 20 'C ? 60
Ch3 enable: ON ? on
>asel ?
Ch1 Td lo : -80 'C
Ch1 Td hi : 20 'C
Ch1 enable: WAIT OK
Ch2 RH lo : 0 %
Ch2 RH hi : 100 %
Ch2 enable: WAIT OK
Ch3 T lo : -40 'C
Ch3 T hi : 60 'C
Ch3 enable: ON
>
AERR Setting the Invalid Output for Analog
Channel
Syntax: AERR<cr>
Analog output gives the invalid value when the output is not enabled
or when analog readings are not available. The value of the invalid
output shall be 4...20 mA.
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