Vaisala HM41 User manual

User’s Guide
www.vaisala.com
M211088EN-C
Vaisala HUMICAP®Hand-Held
Humidity and Temperature Meter
HM40 Series

PUBLISHED BY
Vaisala Oyj
Street address: Vanha Nurmijärventie 21
FI-01670 Vantaa, Finland
Mailing address: P.O. Box 26
FI-00421 Helsinki, Finland
Phone: [phone]
Fax: [phone]
Visit our Internet pages at www.vaisala.com.
© Vaisala 2014
No part of this manual may be reproduced, published
or publicly displayed in any form or by any means,
electronic or mechanical (including photocopying),
nor may its contents be modified, translated, adapted,
sold or disclosed to a third party without prior written
permission of the copyright holder. Translated manuals
and translated portions of multilingual documents are
based on the original English versions. In ambiguous
cases, the English versions are applicable, not the
translations.
The contents of this manual are subject to change
without prior notice.
This manual does not create any legally binding
obligations for Vaisala towards customers or end users.
All legally binding obligations and agreements are
included exclusively in the applicable supply contract
or the General Conditions of Sale and General
Conditions of Service of Vaisala.

1
Table of Contents
Table of Contents................................................................................... 1
First Startup.............................................................................................4
Initial Settings .............................................................................. 4
Product Overview ................................................................................. 5
HM41 – Front............................................................................................ 7
HM41 – Back............................................................................................. 8
HM42 for Tight Spaces .......................................................................9
HM45 – Remote Probe with Handle ............................................ 10
HM46 for Mechanically Demanding Applications ..................12
Batteries ...................................................................................................13
Charging.................................................................................................. 14
Parameters Explained.........................................................................15
Measurement Views ............................................................................16
Screen Layout and Controls.................................................16
Indicators ...................................................................................... 17
Numeric View..............................................................................19
Statistics View ...........................................................................20
Graph View .................................................................................. 21
Hold and Tag..............................................................................23
Main Menu...............................................................................................25
Tagged Points............................................................................26
Graph Duration.......................................................................... 27
Settings.........................................................................................28
Calibration...................................................................................28
Help ................................................................................................29

2
Settings Submenu.............................................................................. 30
Language .....................................................................................30
Units................................................................................................31
Time & Date .................................................................................31
Pressure........................................................................................33
Reminder......................................................................................34
Backlight ......................................................................................35
Battery ..........................................................................................35
Power off .....................................................................................36
Navigation ...................................................................................36
Rounding......................................................................................36
Factory Settings .......................................................................37
How to Measure ...................................................................................38
Application Examples.......................................................................40
Maintenance.......................................................................................... 44
Cleaning........................................................................................44
Changing the Filter..................................................................45
Changing the Probe ................................................................46
Calibration ..............................................................................................47
Calibrating the HM40 Using HMK15 .................................48
Accessories and Parts .......................................................................53
Filters.............................................................................................54
Chargers and Batteries..........................................................55
Belt Clips and Battery Covers.............................................55
Technical Data ......................................................................................56
Relative Humidity and Temperature Measurement
Performance...............................................................................56
Mechanical...................................................................................58

3
General..........................................................................................59
HM41 Dimensions .................................................................... 60
HM45 Dimensions .....................................................................61
HM42 and HM46 Probe Dimensions ................................62

4
First Startup
1. Check that the probe is securely attached and remove
the yellow transport protection cap from the probe.
2. Open the battery cover and insert two AA-size
batteries.
3. Close the battery cover and turn on the meter by
pressing the Power button. If the meter does not turn
on, check the battery orientation. Replace the
batteries with fresh/recharged ones if needed.
Initial Settings
When you power on the HM40 for the first time (or
after a factory reset of the settings), you must first
select the operation language. The meter will then ask if
you want to change the following settings:
-Units
-Date
-Time
If you answer
Yes
to the question (recommended), the
meter will show the settings screens before showing the
measurement view. Use the arrow and function buttons
to select. For more information, see section Settings
Submenu on page 30.
HM40 will retain the date and time even during
battery changes. The clock will have to be set
again only if the meter is without battery power
for several hours.

5
Product Overview
The Vaisala HUMICAP®Hand-Held Humidity and
Temperature Meter HM40 Series comprises four models
designed for various portable measurement
applications. All models in the HM40 series use the
HM40 hand-held indicator with one of four probe
options:
-HM41 – Compact and portable standard option
where a HMP113 probe attaches directly to the
HM40 meter body.
-HM42 – HM40 meter with a spiral cable and handle
connected to an Ø 4mm probe with a length of 235
mm. The structure of the probe is especially suitable
for measurements in tight spaces, such as seams
between wall tiles.
-HM45 – The HM45 uses the same HMP113 probe as
HM41, but with a probe handle connected to the
HM40 meter with a spiral cable, providing additional
reach.
-HM46 – HM40 meter with a spiral cable and handle
connected to a 320 mm robust stainless steel probe
designed for mechanically demanding applications
such as dirty processes and relatively high
temperatures (temporarily up to 180 °C).
For more information on using the probes, see
Application Examples on page 40.
For probe dimensions and technical data, see pages 56
and 60.

6
Main features of the HM40 series:
-Compact and robust housing.
-Measures a wide range of parameters: RH, Td, Tw, a,
x, h, T. See section Parameters Explained on page
15.
-Large graphical display.
-Graphs for selected humidity parameter and
temperature.
-Can be user calibrated (using the HMK15 humidity
calibrator, for example).
-Powered by standard AA size batteries (2×).
-Indicator operation temperature range -10°C ...
+60°C. Probe operation temperature ranges
-40 °C … +180°C, depending on probe model.
-Short (HM41/HM45) or long (HM42/HM46) soft
case, depending on probe length.
-Belt clip.
Optional accessories:
-Different filters for increased protection against
contaminants.
-USB-powered portable charger for AA-size NiMH
rechargeables.
For more information and order codes of the
accessories, see section Accessories and Parts
on page 53.

7
HM41 – Front
HMP113 probe
Filter and sensor
Probe holder
Display
Right function
Left function
Down
Up
Power
Menu

8
HM41 – Back
Belt clip
Battery
cover
Batteries
2 x AA

9
HM42 for Tight Spaces

10
HM45 – Remote Probe with
Handle
HM40
handle
HMP113 probe
Probe
holder
Cable connector
Orientation mark

11
You can connect the HM45 handle to the belt clip for
single handed use. Simply push the belt clip into the slot
in the handle.
When the handle is connected to the meter in this way,
you can lay down the meter on top of the handle.

12
HM46 for Mechanically
Demanding Applications

13
Batteries
The HM40 is powered by
two AA-size batteries
. You
can use the following battery types:
-Alkaline (IEC-LR6)
-Lithium (IEC-FR6)
-NiMH (IEC-HR6)
Do not mix batteries of different types. Both
batteries must be of the same type.
Observe the storage and operation instructions of
the battery manufacturer.
Alkaline batteries are the standard choice in non-
rechargeable batteries. They are a good match for the
power requirements of the HM40.
Lithium batteries are a good choice if you need the
longest battery life or best capacity in low
temperatures. Lithium batteries are not rechargeable.
Do not confuse them with lithium-ion batteries, which
cannot be used in the HM40.
NiMH batteries are rechargeable, and available from
Vaisala as an option. For order codes, see section
Accessories and Parts on page 53. Instructions for using
the optional USB charger are provided in section
Charging on page 14.

14
Charging
The optional USB charger provides a convenient way to
charge two NiMH batteries from any powered USB port
(for example, from a laptop computer).
1. Place the rechargeable batteries in the charger and
plug it into a USB port. The blue LED on top of the
charger starts to blink.
2. When the LED stops blinking and stays on, the
batteries are charged. The charging time is several
hours for two fully discharged NiMH batteries.
If you are not using a Vaisala-supplied charger and
rechargeable batteries, read and follow the
manufacturer’s own charging instructions.
Do not attempt to charge non-rechargeable
(alkaline or lithium) batteries! Doing so leads to a
risk of battery leakage, equipment damage, and
risk of explosion and/or fire.

15
Parameters Explained
The table below describes the parameters measured by
the HM40. All of the parameters are measured or
calculated when the meter is on, independent of what is
currently displayed. The parameters are also described
in the indicator’s Help menu (see page 29).
Parameter Symbol Unit(s) Description
Relative
humidity
RH
%
Ratio of the partial pressure of
water vapor in the air to the
saturation vapor pressure of air
at the current temperature.
Dewpoint Td °C
°F
Temperature at which the water
vapor in the air will condense into
water at the current pressure.
When the dew point is below 0
°C, the meter outputs frost point
instead of dew point.
Wet bulb
temperature
Tw °C
°F
The minimum temperature that
can be reached by evaporative
cooling in the current conditions.
Absolute
humidity
a g/m
3
gr/ft3
Quantity of water in a cubic
meter (or cubic foot) of air.
Mixing ratio
x
g/kg
gr/lb
Ratio of water vapor mass per
kilogram (or pound) of dry air.
Enthalpy h kJ/kg
btu/lb
Sum of the internal energy of a
thermodynamic system.
Temperature T °C
°F
Temperature in Celsius or
Fahrenheit scale.

16
Measurement Views
Screen Layout and Controls
Pressing the right function button holds the screen
and tags the current measurement point.
See Hold and Tag on page 23.
Battery
indicator
Alert indicator
Change quantity
Enter menu
Long press:
tag point
Short press:
tag point and
hold screen
Measurement
display area
Long press: power on/off
Short press: activate backlight
Current quantity
Change
view
Current
view

17
Indicators
Battery charge indicator
Fresh batteries will always show three
bars.
When the indicator shows two bars, the
voltage of the batteries has started to
drop. When there is a single (blinking)
bar left, you should replace the batteries.
The meter will turn off automatically
when the battery voltage drops too low.
Alert indicator
This indicator is shown next to the
battery charge indicator if there is a
measurement problem. The most likely
causes are low battery and probe
problems, for example:
-Battery voltage too low to power the
probe. The measured values may
show asterisks "*" instead of
numbers.
-Probe has been disconnected
-Probe has been damaged
-Probe is incompatible
-Probe is wet (probe recovers
automatically when it dries). The
measured values may show asterisks
"*" instead of numbers.