Vaisala DM70 User Manual
r
USER'S GUIDE
Vaisala DRYCAP® Hand-Held
Dewpoint Mete
DM70
M010091EN-F
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 2007
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.
________________________________________________________________________________
Table of Contents
CHAPTER 1
GENERAL INFORMATION............................................................................6
Safety......................................................................................... 6
General Safety Considerations.............................................6
Feedback...................................................................................6
Recycling ..................................................................................7
Trademarks............................................................................... 7
Warranty....................................................................................8
CHAPTER 2
PRODUCT OVERVIEW.................................................................................. 9
Introduction to Vaisala DRYCAP® Hand-Held Dewpoint
Meter DM70 ............................................................................... 9
Basic Features and Options................................................10
Parts Description.................................................................11
CHAPTER 3
PREPARATIONS BEFORE USE.................................................................13
Installing and Removing the Battery Pack ..........................13
Charging the Battery Pack .................................................... 14
Buttons and Navigation.........................................................15
Turning on the Device............................................................15
CHAPTER 4
DEWPOINT MEASUREMENT.....................................................................17
Measuring ...............................................................................17
CHAPTER 5
USER INTERFACE ...................................................................................... 19
Basic Display.......................................................................... 19
Menus...................................................................................... 20
Display Menu..........................................................................21
Quantities and Units............................................................21
Rounding.............................................................................22
Hold/Save............................................................................ 23
Graphic History ...................................................................23
Functions Menu......................................................................24
Alarm...................................................................................24
Analog Output .....................................................................26
Selecting and Scaling the Analog Output ...................... 26
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Auto-Calibration...................................................................27
Automatic Auto-Calibration.............................................27
Turning off Automatic Auto-Calibration..........................28
Manual Auto-Calibration.................................................28
Sensor Purge.......................................................................29
Turning on/off Automatic Sensor Purge.........................30
Changing Automatic Sensor Purge Interval...................30
Manual Sensor Purge.....................................................31
Calibrate Transmitters (used only with DMP248)................32
Recording/Viewing Menu.......................................................32
Recording Data....................................................................32
Stopping Recording........................................................34
View Recorded Data ...........................................................34
Memory Status ....................................................................34
Clear Data Memory .............................................................35
Transferring Recorded Data to PC......................................35
Environment Menu .................................................................36
Pressure Settings................................................................36
Settings Menu.........................................................................37
User Interface......................................................................37
Language .......................................................................37
Automatic Power Off ......................................................38
Program Shortcut Keys..................................................38
Button Tones and Backlight ...........................................39
Date and Time.....................................................................39
Measurement Settings ........................................................40
Automatic Auto-Calibration.............................................40
Automatic Purge.............................................................40
Molecular Weight............................................................40
Purge Interval.................................................................41
Device Information...............................................................41
Factory Settings...................................................................42
CHAPTER 6
FIELD CALIBRATION CHECK OF FIXED TRANSMITTERS.....................43
Field Calibration Check of DMT340/DMT242/DMT142 ........43
Field Calibration Check of DMP248......................................44
CHAPTER 7
SAMPLING FROM PROCESSES................................................................47
Sampling Cells........................................................................48
DSC74.................................................................................48
DSC74B...............................................................................49
DSC74C ..............................................................................49
DMT242SC..........................................................................52
DMT242SC2........................................................................52
Connection to Pressurized Processes Using the DSC74
Sampling Cell..........................................................................52
DSS70A Sampling System.....................................................54
DSS70A Sampling Procedure.............................................55
DSS70A Maintenance.........................................................56
Recharging the Battery...................................................56
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Changing the Battery .....................................................57
Changing the Filter......................................................... 59
Changing the Fuses.......................................................60
CHAPTER 8
MEASURING MOISTURE IN SF6 GAS-INSULATED EQUIPMENT...........61
Overview .................................................................................61
Operating Environment.......................................................62
Measuring............................................................................62
CHAPTER 9
CALIBRATION, ADJUSTMENT, AND MAINTENANCE............................. 65
Calibration............................................................................... 65
User Calibration and Adjustment........................................65
Adjusting DM70.............................................................. 66
Adjusting DMT340 Series Transmitters Using DM70 as
Reference or Terminal...................................................66
Adjusting Dewpoint................................................................67
Two-Point Relative Humidity Adjustment............................67
Two-Point Relative Humidity Adjustment of DMT340
Series Transmitters Using DM70...................................68
Adjusting Dewpoint T
T
Adjustment of DM70.................................................70
d/f
T
Adjustment of DMT340 Series Transmitters using
d/f
........................................................70
d/f
DM70..............................................................................71
To Same as T
......................................................72
d/f I/II
1-Point Adjustment....................................................73
Adjusting Temperature..........................................................74
Temperature Adjustment of DM70......................................74
One-Point Adjustment....................................................74
Two-Point Adjustment....................................................75
Temperature Adjustment of DMT340 Series Using DM70 .75
To Same as T
..............................................................76
I/II
1-Point Adjustment......................................................... 76
2-Point Adjustment......................................................... 77
Vaisala Service Centers......................................................... 78
CHAPTER 10
DE-COMMISSIONING, DISMANTLING, AND DISPOSAL.........................79
CHAPTER 11
TECHNICAL SPECIFICATIONS..................................................................81
Measured Variables................................................................81
Dewpoint Temperature........................................................81
Temperature...................................................................83
PPM (ppmv or ppmw)......................................................83
Absolute Humidity (DMP74A Probe Recommended)....84
Mixing Ratio (DMP74A Probe Recommended).............84
Relative Humidity (DMP74A).........................................84
Measurement Environment............................................84
Probe General................................................................85
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MI70 Indicator......................................................................85
DMP74 Probe + MI70 Indicator = Vaisala DRYCAP® DM70
Hand-Held Dewpoint Meter.................................................86
Accessories.........................................................................89
Dimensions..........................................................................90
List of Figures
Figure 1 Hand-Held Dewpoint Meter DM70............................................11
Figure 2 Installing the Battery Pack........................................................13
Figure 3 Buttons......................................................................................15
Figure 4 Basic Display............................................................................19
Figure 5 Menus.......................................................................................21
Figure 6 Quantities and Units Menu.......................................................22
Figure 7 Alarm ........................................................................................24
Figure 8 Analog Output...........................................................................26
Figure 9 Auto-Calibration Displays.........................................................29
Figure 10 Sensor Purge Displays.............................................................31
Figure 11 Calibrate Transmitters Display .................................................32
Figure 12 Recording .................................................................................32
Figure 13 Environment Menu ...................................................................36
Figure 14 User Interface...........................................................................37
Figure 15 Hold/Save Replaced by Auto Cal.............................................39
Figure 16 Measurement Settings Menu....................................................40
Figure 17 Device Information....................................................................41
Figure 18 Indicator and Probe Information...............................................42
Figure 19 Calibrate Transmitters Message...............................................45
Figure 20 DSC74 Sampling Cell with the Adapters..................................48
Figure 21 DSC74B....................................................................................49
Figure 22 Default Assembly of DSC74C ..................................................50
Figure 23 Alternative Assembly of DSC74C for Tight Spaces .................51
Figure 24 DMT242SC and DMT242SC2 Sampling Cells.........................52
Figure 25 DM70 with the Case .................................................................55
Figure 26 Lifting the System.....................................................................57
Figure 27 Sampling System Upside Down...............................................58
Figure 28 Changing the Filter ...................................................................59
Figure 29 Gas Collection Option...............................................................62
Figure 30 Removing the Leak Screw........................................................63
Figure 31 DMP74A Accuracy ...................................................................82
Figure 32 DMP74B Accuracy ...................................................................82
Figure 33 DMP74C Accuracy ...................................................................82
Figure 34 Dimensions in Millimeters (Inches)...........................................90
Indicator General............................................................85
Battery Pack...................................................................86
General...........................................................................86
Electromagnetic Compatibility........................................87
Sampling Cells ...............................................................87
DMT242SC Sampling Cell........................................87
DMT242SC2 Sampling Cell with Swagelok
Connectors................................................................87
DSC74 Sampling Cell for Pressurized Gases...........87
DSC74B Two-Pressure Sampling Cell .....................87
DSC74C....................................................................88
DMCOIL ....................................................................88
DSS70A Sampling System.............................................88
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List of Tables
Table 1 Measurement Intervals and Maximum Recording Times.........33
Table 2 List of Accessories ...................................................................89
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CHAPTER 1
GENERAL INFORMATION
Safety
General Safety Considerations
WARNING
CAUTION
NOTE
Feedback
Throughout the manual, important safety considerations are
highlighted as follows:
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.
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
6 ___________________________________________________________________ M010091EN-F
Chapter 1 ________________________________________________________ General Information
Recycling
Recycle all applicable material.
Dispose of batteries and the unit according to statutory regulations.
Do not dispose of with regular household refuse.
Trademarks
DRYCAP® is a registered trademark of Vaisala. Microsoft®,
Windows®, and Windows NT® are registered trademarks of Microsoft
Corporation in the United States and/or other countries.
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USER'S GUIDE____________________________________________________________________
Warranty
Vaisala hereby represents and warrants all Products
manufactured by Vaisala and sold hereunder to be
free from defects in workmanship or material
during a period of twelve (12) months from the date
of delivery save for products for which a special
warranty is given. If any Product proves however to
be defective in workmanship or material within the
period herein provided Vaisala undertakes to the
exclusion of any other remedy to repair or at its
own option replace the defective Product or part
thereof free of charge and otherwise on the same
conditions as for the original Product or part
without extension to original warranty time.
Defective parts replaced in accordance with this
clause shall be placed at the disposal of Vaisala.
Vaisala also warrants the quality of all repair and
servi
ce works performed by its employees to
products sold by it. In case the repair or service
works should appear inadequate or faulty and
should this cause malfunction or nonfunction of the
product to which the service was performed Vaisala
shall at its free option either repair or have repaired
or replace the product in question. The working
hours used by employees of Vaisala for such repair
or replacement shall be free of charge to the client.
This service warranty shall be valid for a period of
six (6) months from the date the service measures
were completed.
This warranty does not however apply when the
has been caused through
defect
a) normal wear and tear or accident;
b) misuse or other unsuitable or unauthorized use
of
the Product or negligence or error in storing,
maintaining or in handling the Product or any
equipment thereof;
c) wrong installation or assembly or failure to
service the
Vaisala's service instructions including any
repairs or installation or assembly or service
made by unauthorized personnel not approved
by Vaisala or replacements with parts not
manufactured or supplied by Vaisala;
d) modifications or changes of the Product as well
as an
y adding to it without Vaisala's prior
authorization;
e) other factors depending on the Customer or a
ird party.
th
Notwithstanding the aforesaid Vaisala's liability
nder this clause shall not apply to any defects
u
arising out of materials, designs or instructions
provided by the Customer.
Product or otherwise follow
This warranty is however subject to following
nditions:
co
a) A substantiated written claim as to any alleged
s shall have been received by Vaisala
defect
within thirty (30) days after the defect or fault
became known or occurred, and
b) The allegedly defective Product or part shall,
shoul
d Vaisala so require, be sent to the works
of Vaisala or to such other place as Vaisala may
indicate in writing, freight and insurance
prepaid and properly packed and labelled,
unless Vaisala agrees to inspect and repair the
Product or replace it on site.
This warranty is expressly in lieu of and excludes
all o
ther conditions, warranties and liabilities,
express or implied, whether under law, statute or
otherwise, including without limitation any implied
warranties of merchantability or fitness for a
particular purpose and all other obligations and
liabilities of Vaisala or its representatives with
respect to any defect or deficiency applicable to or
resulting directly or indirectly from the Products
supplied hereunder, which obligations and
liabilities are hereby expressly cancelled and
waived. Vaisala's liability shall under no
circumstances exceed the invoice price of any
Product for which a warranty claim is made, nor
shall Vaisala in any circumstances be liable for lost
profits or other consequential loss whether direct or
indirect or for special damages.
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Chapter 2 __________________________________________________________ Product Overview
CHAPTER 2
PRODUCT OVERVIEW
Introduction to Vaisala DRYCAP® Hand-Held Dewpoint Meter DM70
DM70 measures dewpoint temperature accurately in a measurement
range from -60 °C up to +60 °C depending on the probe version.
DM70 incorporates the advanced DRYCAP® technology, which
enables reliable and high-performance dewpoint measurement. DM70
measures the following quantities:
- dewpoint/frost point1) temperature T
- dewpoint temperature
- temperature T (°C/°F)
- dewpoint/frost point in the atmospheric pressure T
(°C atm/°F atm)
- dewpoint in the atmospheric pressure Td (°C atm/°F atm)
- relative humidity RH (%)
- humid air /dry air H2O ppmv/ppm
- absolute humidity a (g/m3)
- mixing ratio x (g/kg)
1)
T
shows the dewpoint temperature above the freezing point (0
d/f
°C/32 °F) and frost point temperature Tf (dewpoint over ice) below the
freezing point. This is considered as the industry standard.
2)
Td (°C/°F)
w
(°C/°F)
d/f
d/f
2)
Td shows the dewpoint over water throughout the entire
measurement range.
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DM70 consists of two main units: the MI70 indicator and DMP74
probe, versions A, B, or C. DM70 can be used with the optional
sampling cell to measure process dewpoint. With DSS70A, DM70
forms a part of a complete portable sampling system for measuring
process dewpoint.
Basic Features and Options
DM70 has the following basic features and options:
- Numerical and graphical multilingual displays.
- Data recording possibility.
- A tool for checking the reading of the fixed transmitters DMT340,
DMP248, DMT242 and DMT142
- A possibility for an analog output (voltage signal
0 ... 1 V)
- An optional, ready-to-use Microsoft Windows® software, which
allows an easy way to handle measurement data using a serial line
or a USB instrument cable
- The optional sampling system DSS70A (see section DSS70A
Sampling System on page 54)
10 __________________________________________________________________ M010091EN-F
Chapter 2 __________________________________________________________ Product Overview
Parts Description
0403-031
Figure 1 Hand-Held Dewpoint Meter DM70
The following numbers refer to Figure 1 above.
1 = MI70 indicator
2 = DMP74 probe
3 = Sampling cell DSC74 (optional)
4 = Calibration button
5 = Recharger connector
6 = Connector ports for probes and cables
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12 __________________________________________________________________ M010091EN-F
Chapter 3 ____________________________________________________ Preparations Before Use
CHAPTER 3
PREPARATIONS BEFORE USE
Installing and Removing the Battery Pack
NOTE
If you have previously used a battery pack, put the metal contact at
the lower end of the batteries before installing the alkaline batteries.
If DM70 is ordered with a battery pack, it is already installed at the
factory.
1. Unscrew the back plate of the indicator.
2. Remove the old batteries. Detach the black connector by pulling
it up carefully from the wires.
0403-032
Figure 2 Installing the Battery Pack
3. Connect the black connector of the new battery pack. Make sure
the red and black wires are on the upper edge of the connector.
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USER'S GUIDE____________________________________________________________________
Do not push the connector with any conducting material. See
Figure 2 on page 13.
NOTE
NOTE
If you have previously used alkaline batteries, remove the metal
contact before installing the battery pack.
4. Replace the battery pack, close the back plate, and tighten the
screw.
5. Charge the battery before use.
Old batteries must be disposed of according to the local laws and
regulations.
Charging the Battery Pack
NOTE
Do not use DM70 during the first charging.
1. Plug the recharger connector to the base of the indicator.
2. Connect the recharger to a wall socket. A battery sym bol in the
corner of the display will start rolling.
3. When the battery symbol stops rolling, the battery pack is fully
charged.
4. Disconnect the recharger.
The duration of recharging is typically 4 hours. However, the
recommended first charging time is 6 hours.
14 __________________________________________________________________ M010091EN-F
Chapter 3 ____________________________________________________ Preparations Before Use
Buttons and Navigation
To turn on the device, press the Power On/Off button. To open
menus, press an arrow button and then press the shortcut buttons. To
activate a function shown above the shortcut button, press the shortcut
button. To navigate in the menus, press arrow buttons.
0403-033
Figure 3 Buttons
The following numbers refer to Figure 3 above.
1 = Shortcut buttons
2 = Arrow buttons
3 = Power on/off button
Turning on the Device
1. Connect the probe to either one of the base connectors in the
indicator.
2. Press the Power On/Off button.
3. Press any of the arrow buttons and open a menu by pressing
Open.
4. Select Settings using the buttons and press .
5. Select User interface and press .
6. Select Language and press Set.
7. Select the language using the buttons. Confirm the
selection by pressing Select.
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8. If you want to set the date at this point, return to the Settings
menu by pressing .
NOTE
The language can be selected also later. See section Language on
page 37.
9. To change the date, select Date and press Set. Then change
the date using the buttons. To confirm the selection, press
Select. As a default, the date format is year-month-day You
can select from two other alternative formats.
10. To change the time, select Time and press Set. Then change
the time by using the arrow buttons. Confirm the selection by
pressing OK. As a default, the time format is based on the
24-hour clock. If you want to use the 12-hour clock, select 12-
hour clock and then press On.
11. To return to the basic display, press Exit.
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Chapter 4 _____________________________________________________ Dewpoint Measurement
CHAPTER 4
DEWPOINT MEASUREMENT
The following recommendations should be taken into account when
measuring in very dry environments.
- A clean environment is always best for humidity measurements.
Measuring
- The number of connections should be minimized to avoid leaks.
- The flow rate must be adequate.
- Dead ends must be avoided as they cannot be flushed easily.
- The tube temperature must never lie under the dewpoint of the
sample gas. This may lead to condensation and false results.
- The sample tubing should be of as short length as possible. The
surface area should be minimized using the narrowest tubing that
the flow conditions allow.
- The surface finish of the pipework is important. Polished or
electro-polished steel is recommended for best results.
- Hygroscopic materials should be avoided in the sampling lines. Use
stainless steel membranes instead of rubber membranes.
- Impermeable materials should be selected to avoid inward diffusion
of moisture through the sampling tubes and enclosures. Such
impermeable materials are, for example, high-quality stainless steel
and metals. Avoid PVC or nylon tubes.
If you start DM70 for the first time, see section Preparations Before
Use on page 13. Otherwise, follow the instructions below.
1. Connect the probe to the MI70 indicator.
2. Press the Power On/Off button.
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3. Install the probe to the measuring position. If you are measuring
in pressurized processes, see section Connection to Pressurized
Processes Using the DSC74 Sampling Cell on page 52. When
using other sampling cells than DSC74, make sure that the
threads are compatible with the probe threads (G ½" ISO228/1).
Be careful not to damage the sintered filter when installing the
probe.
4. Before measuring, make sure that the air pressure settings of
DM70 are correct and that auto-calibration has taken place (see
section Automatic Auto-Calibration on page 27)
5. The basic display opens. Let the reading stabilize.
CAUTION
NOTE
If you need to disconnect the probe from the indicator, first press the
Power On/Off button to turn the indicator off. This ensures that all
the settings and data are saved properly.
When measuring low dewpoints, the stabilization times can be long,
for example, one to two hours. Therefore, turn off the automatic
power-off function (see section Automatic Power Off on page 38),
turn on the automatic auto-calibration (see section Automatic AutoCalibration on page 27), and turn on the automatic sensor purge (see
section Turning on/off Automatic Sensor Purge on page 30).
Thus, the stabilization can be monitored, the auto-calibration ensures
an accurate measurement, and the purge ensures the shortest possible
response times.
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Chapter 5 _____________________________________________________________User Interface
CHAPTER 5
USER INTERFACE
This chapter contains information that is needed to operate this
product.
Basic Display
When DM70 is turned on, the display shown in Figure 4 below
appears.
0403-034
Figure 4 Basic Display
The following numbers refer to Figure 4 above.
1 = The state of the battery.
2 = Pressure settings.
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3 = Selected quantities. Up to three of the following quantities
can be selected at a time: dewpoint (T
d/f, Td
), relative
humidity (RH), absolute humidity (a), mixing ratio (x), parts
per million (H2O), temperature (T).
4 = The Graphic1) shortcut button changes the display into a
curve mode.
5 = The Hold/Sa1) shortcut button holds the display and allows
you to save the reading into the memory.
6 =
The Record shortcut button takes you to the
Recording/Viewing menu. This is the default shortcut
button. In the figure it has been changed to Start/S.
1)
The Graphic, Hold/Sa, and Record functions above the shortcut
buttons are set at the factory. You can change them to refer to other
functions as shown in Figure 4 on page 19 where Start/S has replaced
Record. See also section Program Shortcut Keys on page 38.
Menus
The settings can be changed and functions can be selected in the
menus. Follow the instructions below:
1. Open the main menu by pressing one of the buttons.
2. Press Open within 5 seconds. Otherwise, the basic display
returns. If this happens, start from step 1 again.
3. Move in the menus using the
4. Select an item with the
button.
buttons.
5. To return to the previous level, press .
6. To return to norm al operation, press Exit.
20 __________________________________________________________________ M010091EN-F
Chapter 5 _____________________________________________________________User Interface
0403-035
Figure 5 Menus
Display Menu
Quantities and Units
You can select 1 ... 3 display quantities at a time. The unit of
quantities (T
default is °C.
To select a quantity, do the following:
VAISALA_______________________________________________________________________ 21
, Td, or T) can be selected between °C or °F. The
d/f
USER'S GUIDE____________________________________________________________________
1. Open the menu by pressing Open.
2. Select Display and press .
3. Select Quantities and units and then press .
4. To select a quantity, move on the desired quantity using the
arrow buttons and then press Select.
5. To change the unit, move on the desired quantity using the
arrow buttons and then press Unit (°C or °F).
6. To hide a quantity, move on the desired quantity using the arrow
buttons and then press Hide.
7. To return to the basic display, press Exit.
8. If you want to check the environment settings, press
Yes. Otherwise press No.
NOTE
Units °C atm and °F atm indicate that the dewpoint or frost point is
converted from process pressure to atmospheric pressure.
Below you will find an example of the Quantities and Units menu.
0404-021
Figure 6 Quantities and Units Menu
Rounding
You can select a one- or two-decimal display using Rounding. As a
default, rounding is turned off
(=a two-decimal display is in use).
1. Open the menu by pressing Open.
2. Select Display and then press .
3. Select Rounding.
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Chapter 5 _____________________________________________________________User Interface
4. To turn rounding on (=a one-decimal display), press
On. To turn rounding off (=a two-decimal display), press
Off.
5. To return to the basic display, press Exit.
NOTE
Rounding does not affect the measurement accuracy. Accuracy is
defined in Chapter 11 on page 81.
Hold/Save
With the Hold/Save function you can hold a selected display reading
and save it into the memory. Several readings can be saved. The
reading saved first is called data point 1, the second saved reading is
called data point 2 , and so on. All the individual readings (data
points) are stored in the same file marked with
in the indicator memory even when the indicator is switched off.
1. Open the menu by pressing Open.
2. Select Display and then press .
3. Select Hold/Save display.
4. To hold the display, press Hold. The measurement data is
displayed.
. The file will remain
5. To save the reading, press Save. To return to the basic
display, press Exit.
6. To view the saved readings, press
display. Then select View recorded data and press .
7. Select the file marked with
the saved data readings. To view the recording time stamps,
press
8. To return to the basic display, press
Times.
and press . Now you can view
Record in the basic
Exit.
Graphic History
The graphical display shows the measurements as a curve. From the
curve, you can examine the data trend and history of the last minutes.
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USER'S GUIDE____________________________________________________________________
The graphical display shows the curve of the uppermost quantity
shown in the basic display.
1. Open the menu by pressing Open.
2. Select Display and press .
3. To go to the Graphical history display, select Graphic history
and press Show.
4. To get the statistical info on the graph area (minimum,
maximum, and average values), press
Info.
5. To get the curve of the other selected quantities, press
To get the curves of all the quantities, press Next until the
text ALL appears on the display. Then press All.
6. To zoom in a curve, press . To zoom out, press . To move
the curve horizontally, press .
7. To return to the basic display, press Back and Exit.
Functions Menu
Alarm
0403-042
Next.
Figure 7 Alarm
When the alarm goes off, DM70 beeps and the backlight blinks. The
alarm is turned on when the measured value is not between the alarm
limits, that is, the permitted area. The alarm level(s) can be set for
only one quantity at a time. To set the alarm levels, follow the
instructions below:
1. Open the menu by pressing
2. Select Functions and press .
3. Select Alarm and press .
24 __________________________________________________________________ M010091EN-F
Open.
Chapter 5 _____________________________________________________________User Interface
4. Select Quantity and press Set to select the quantity.
5. Select the quantity and press Select. Only one active quantity
can be selected at a time. To change which quantities are active,
go to Menu - Display - Quantities and units.
6. Select the first limit and press Set (if the alarm function is
on, turn it off). Use the arrow buttons to set the alarm level. To
select the sign for the alarm level, press the +/- button. To
save the settings, press
OK.
7. Select the second limit and follow the instructions in step 6. The
alarm will go off when either the upper or lower limit is
exceeded.
If you will use only one limit, for example, if you want to detect
if the dewpoint will rise above -40 °C, do the following:
Set the upper limit to -40 °C and the value of the lower limit so
low that it will never be reached, for example, to -80 °C. Thus,
DM70 will alert when Td rises above
-40 °C.
NOTE
8. To activate the alarm and to return to the basic display, select
Alarm On/Off and press On. The note symbol ♫ will appear
in the upper left corner of the display.
9. When the alarm level is reached, you can stop the alarm by
pressing OK. To reactivate the alarm, press Yes. To
completely stop the alarm, press
No.
The alarm does not work when the device is turned off.
VAISALA_______________________________________________________________________ 25
USER'S GUIDE____________________________________________________________________
Analog Output
Selecting and Scaling the Analog Output
0403-052
Figure 8 Analog Output
To get analog measurement data, an analog signal cable is needed (see
section Accessories on page 89).
1. Connect the signal cable connector of the analog output to the
base connector of the indicator. Connect the screw terminal
block as follows:
Brown wire: common wire (-)
Yellow-green wire: signal (+)
2. Open the menu by pressing Open.
3. Select Functions and press .
4. Select Analog output and press .
5. Select Quantity and press Set.
6. Select Quantity and press
can be selected at a time. To change the quantities, go to Menu -
Display - Quantities and units.
Select. Only one active quantity
7. To set the value for the 0.0 V output signal, select
0.0 V and press
Set the low value using the arrow buttons. To select the sign for
the value, press
8. To set the value for the 1.0 V output signal, select
1.0 V and press Set. Set the high value using the arrow
buttons. To select the sign for the value, press
+-. To confirm the setting, press OK.
9. To activate the analog output and to return to the basic display,
select Analog output on/off and press On. The following
symbol ~ appears in the upper left corner of the basic display.
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Set. If the analog output is on, turn it off.
+-.
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