Vaisala HMP42 User Manual

OPERATING MANUAL

HMI41 Indicator

and HMP42 Probe

M210317EN-A

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The instruction manuals may be changed without prior notice.

HMI41 AND HMP42

M210317EN-A Operating Manual

Contents

1. THE HMI41 INDICATOR AND PROBES...............................................................................1

2. TO BE NOTED IN THE M EASUREMENT OF HUM IDIT Y.....................................................3

3. GETTING STARTED............................................................................................................4

3.1 Inserting the batteries............................................................................................. 4

3.2 Connecting the HMP42 probe ................................................................................. 4

3.3 Starting the measurements ....................................................................................4

3.4 Using the HMP42 for measuring equilibrium humidity in structures ................... 5

3.4.1 Example 1: measuring hum idity in a bathroom .......................................... 5

3.4.2 Example 2: measuring hum idity in a concrete floor .................................... 6

3.4.3 Erroneous installations..............................................................................7

4. HOW TO USE THE HM I41 INDICATOR AND HMP42 PROBE............................................. 8

4.1 Turning the indicator on......................................................................................... 8

4.2 Measurement readings on display ......................................................................... 9

4.3 HOLD-mode........................................................................................................... 10

4.3.1 MIN-mode............................................................................................... 10

4.3.2 MAX-mode.............................................................................................. 10

5. CALIBRATION...................................................................................................................11

5.1 How to use the HMP42 calibration adapter .......................................................... 11

5.2 Calibration with trimmer potentiometers............................................................. 12

5.2.1 Humidity calibration................................................................................. 12

5.3 Calibration with HMI41 software commands ....................................................... 14

5.3.1 One point humidity calibration ................................................................. 16

5.3.2 Two point humidity calibration ................................................................. 18

5.3.3 One point temperature calibration ...........................................................20

5.3.4 Two point temperature calibration ...........................................................22

6. HMI41 AND DATA COLLECTING ...................................................................................... 25

6.1 Entering the data collecting mode....................................................................... 25

6.2 Manual data collecting..........................................................................................26

6.3 Setting the measurement duration ....................................................................... 27

6.4 Setting the measurement interval ........................................................................ 27

6.5 Reading the measurement results ....................................................................... 28

6.5.1 MIN and MAX in data collecting

REC READ mode ..................................... 30

7. TRANSFERRING THE STORED READINGS TO A PC...................................................... 31

7.1 Giving the communication parameters................................................................31

7.2 Transferring the data ............................................................................................ 34

8. SETUP PROCEDURE ........................................................................................................ 37

8.1 Entering the setup mode ...................................................................................... 37

8.2 Selecting the display units................................................................................... 38

8.3 Setting the automatic power-off function............................................................ 39

HMI41 AND HMP42 Operating Manual M210317EN-A

8.4 Selecting the display quantities ........................................................................... 39

8.5 Setting the pressure for mixing rat io and w et bu lb temperat ure calculatio ns..40

8.6 Selecting the probe type.......................................................................................40

9. MAINTENANCE.................................................................................................................. 41

9.1 Changing the filter and the sensor head set........................................................ 41

9.2 Chemical tolerances of the HUMICAP



MINI sensor.............................................41

9.3 Spare parts and accessories.................................................................................42

10. IN CASE OF ERROR.......................................................................................................... 43

10.1 Trouble shooting ...................................................................................................43

10.2 Checking the settings ........................................................................................... 44

11. TECHNICAL DATA.............................................................................................................45

11.1 HMI41 indicator......................................................................................................45

11.2 HMP42 probe.......................................................................................................... 46

11.4 Accuracy of the calculated quantities..................................................................48

11.5 Electromagnetic compatibility..............................................................................51

APPENDIX 1: QUICK REFERENCE GUIDE ...............................................................................52

WARRANTY

This manual is valid for programme versions 2.01 or greater.

HMI41 AND HMP42

M210317EN-A Operating Manual

1. THE HMI41 INDICATOR AND PROBES

The HMI41 is an easy-to-use portable humidity and temperature indicator for a variety of applications, including such as industrial monitoring and inspections, occupational health and safety, laboratory and research use, spot checking etc. When equipped with optional calibrati on cables, the HMI41 can also be used as a field calibrator for most Vaisala transmitters.

The HMI41 has as many as six different probe types to choose from. The indicator recognizes the probe type automatically, so there is no need to change settings each time the probe is changed. However, please, note that this feature is active only in indicators and probes with letters ID in the instrument label. For previous versions, the probe type has to be set manually. The HMP44 is an exception, as indicators marked with ID recognize automatically all versions of this probe. All probe types are optimized for different applications:

• HMP41 probe can be used for measuring humidity and temperature in

numerous applications, for example in spot checks.

• HMP42 probe head has a diameter of only 4 mm. The HMP42

consists of a handle a 23.5 cm long probe head. This remarkably small and round probe structure is specially indicated for measurements in very tight spaces, e.g. in joint spaces between tiles and in air conditioning channels, as well as for measuring the equilibrium humidity of e.g. timber; the operating temperature range is

-40 - +100 °C.

• HMP44 and HMP44L are used for measuring humidity in concrete

and other structures.

• HMP45 probe is indicated for measurements in channels and other

places that are difficult to reach and therefore require a probe head with cable.

• HMP46 probe is optimized for measurements in relatively high

temperatures (up to +100 °C, temporarily even +180 °C), in dirty processes and in general in applications that require a robust probe structure.

HMI41 AND HMP42 Operating Manual M210317EN-A

The HMI41 indicator displays relative humidity, temperature and dewpoint

temperature readings. In addition to these, one of the following quantities can also be chosen: absolute humidity, wet bulb temperature or mixing ratio.

The indicator also features an automatic power-off function which can be

disabled, and a continuously updated display. The display can be frozen to show the current readings, and it can be used for checking the minimum and maximum readings measured during data collecting. The automatic power-off function is not active during data collecting even if it was previously selected.

The versatile HMI41 indicator also includes a data collecting feature. Data

collecting can be either automatic or manual, and it can be optimized for each application: both the measurement interval and duration can be set by the user. During automatic data collecting, the probe takes measurements only just before storing each measurement. In order to minimize the consumption and to maximize the battery life, the power is automatically turned off for the measurement interval and the display is dim except when the readi ngs on the display are updated (once a minute). The stored readings can be transferred to a PC via a serial interface (order code 19446ZZ) and then printed, if required.

The humidity measurement range is 0 - 100 %RH. The temperature measure-

ment range with the HMP42 probe is -40 - +100 °C. Relative humidity is measured with the accurate and stable HUMICAPMINI humidity sensor which uses an operating principle based on the changes in the capacitance of the sensor as its thin polymer film absorbs water molecules.

HMI41 AND HMP42

M210317EN-A Operating Manual

2. TO BE NOTED IN THE MEASUREMENT OF HUMIDITY

In the measurement of humidity and especially in calibration it is essential that

temperature equilibrium is reached. Even a small difference in temperature between the measured object and the sensor causes an error. If the t emperature is +20 °C (+68 °F) and the relative humidity is 50 %RH, a difference of +1 °C between the measured object and the sensor causes an error of +3 %RH. When the humidity is 90 %RH, the corresponding error is + 5.4 %RH.

The error is at its greatest when the sensor is colder or warmer than the

surroundings and the humidity is high. Although the humidity sensor reacts rapidly to changes in the amount of water vapour in the air, the probe temperature changes more slowly. To avoid errors caused by temperature differences the probe must always be left to stabilize to ambient temperature before starting measurements: the bigger the temperature difference, the longer the stabilization time.

Indoors relative humidity should be measured in a place where the temperature

is as close to the average temperature of the room as possible. Measurements taken close to heat sources will not give a true picture of the relative humidity in the whole room.

9 8 7 6 5 4

dRH (%RH)

3 2 1 0

-40-200 20406080100 Temperature (°C)

Figure 2.1 Measurement error at 100 %RH when the dif ference

between the ambient and the sen sor temperature is 1 °C

HMI41 AND HMP42 Operating Manual M210317EN-A

3. GETTING STARTED

3.1 Inserting the batteries

When taking the HMI41 indicator into use, first insert the batteries (4 pcs of

size AA [LR6] batteries). Open the lid on back of the device and insert the batteries as indicated in the housing. Then close the lid carefully.

3.2 Connecting the HMP42 probe

Connect the HMP42 probe cable to the connector marked 'PROBE' at the

bottom of the HMI41 indicator (see Figure 3.2.1).

NOTE

If the indicator does not have letters ID in the

instrument label (on the back of the indicator), you must give the probe setting manually before starting the measurements (see Chapter 8).

HMP42 cable

Figure 3.2.1 Connecting the HMP42 probe to the HMI41

3.3 Starting the measurements

Before starting the measurements with the HMP42, remember to allow enough time for stabilization.

Turn the power on with the ON/OFF button and the following appears:

Td T

P set min max hyst hold Lo bat Hi

% °C °F

°C

°F

Pahg/m

Within a couple of seconds, the display changes to show the software version

and the probe type (42.46):

HMI41 AND HMP42

M210317EN-A Operating Manual

NOTE: if the following appears, check that the probe is correctly connected:

If the software version does not appear, it is smaller than 1.02 and the

indicator cannot be used with the HMP42 probe. If the probe type does not appear, the indicator is of a previous version and does not recognize the probe type automatically; give the setting manually (see Chapter 8).

In a couple of seconds, the battery charge appears and after that, the first

measurement readings:

T°C

More detailed instructions of use are given in Chapter 4.

3.4 Using the HMP42 for measuring equilibrium humidity in structures

The HMP42 has been optimized for taking measurements in structures and tight places. The following photos illustrate some examples of use in these applications.

3.4.1 Example 1: measuring humidity in a bathroom

In this example, the screw of the shower holder is removed; no drilling is

needed as the HMP42 is small enough to enter this screw hole.

Figure 3.4.1 Taking measurements in a bathroom

HMI41 AND HMP42 Operating Manual M210317EN-A

3.4.2 Example 2: measuring humidity in a concrete floor

Bore a hole and clean it thoroughly so that all drilling dust comes out; blowing air is a good method for cleaning. However, please, note that if you clean several holes, you should use a mask to protect yourself against dust. You can also use a vacuum cleaner. Seal the hole e.g. with tape. Let stabilize (e.g. 24 hours in concrete). Cut the tape, insert the probe in the hole and take measurements. See photos below for steps 1 - 6.

1. Bore a hole. 2. Clean it. 3. Seal it and let stabilize.

4. Cut the tape. 5. Insert the probe. 6. Take measurements.

Figure 3.4.2 Taking measurements in concrete floors

HMI41 AND HMP42

M210317EN-A Operating Manual

3.4.3 Erroneous installations

Please, note that although with a metal probe head, the HMP42 is a delicate instrument and requires careful handling. The probe must never be strongly bent or forced through anything; if necessary, use e.g. a sharp edged pin with a diameter of 5 mm. The filter must not be twisted. When taking measurements in structures, never leave the cable and indicator hanging down while leaving the probe to stabilize (see photos below). Make sure that when mounted horizontally, the probe is at least 4 cm inside the structure in order to avoid bending. See the following photos and make sure that your installation is not like the one on the right.

at least 4 cm inside the structure

Figure 3.4.3 Installation: correct way on the left,

erroneous on the right

HMI41 AND HMP42 Operating Manual M210317EN-A

4. HOW TO USE THE HMI41INDICATOR AND HMP42 PROBE

4.1 Turning the indicator on

To start the measurements with the HMI41, just press the ON/OFF button and

the following text appears:

Td T

P set min max hyst hold Lo bat Hi

% °C °F

°C

°F

Pahg/m

After a few seconds, the software version and probe type indication appear:

If the software version does not appear, it is smaller than 1.02 and the HMI41

cannot be used with the HMP42. Contact Vaisala or a Vaisala representative for further information.

Make sure that you can see the text 42.46 on the display. If not, the indicator

is of a previous version and does not recognize the probe type automatically. Give the probe type setting manually (see Chapter 8).

After a couple of seconds, the battery voltage appears on the display with an

indication of the battery charge (high or low):

bat

If the battery voltage is higher than 4.75 V, the text on the lower righthand

corner is “bat HI” and after a few seconds, the HMI41 automatically displays the RH and T readings. If the voltage is 4.65...4.75 V, the text is “Lo bat” and the batteries should be replaced (see Chapter 3.1). If the voltage is lower than

4.65 V, the indicator turns itself off to prevent erroneous measurements and readings. Should this happen, replace the batteries.

HMI41 AND HMP42

M210317EN-A Operating Manual

4.2 Measurement readings on display

Relative humidity and temperature readings appear automatically after the

battery charge indication:

T°C

If MODE button is pressed, dewpoint temperature (Td) reading is displayed:

Td T

When the MODE button is pressed again, one of the following is displayed or

°C °C

the HMI41 returns to showing the RH and T readings according to what has been chosen for the measurement quantities (see Chapter 4.4):

°C

g/m

Temperature and absolute humidity

abs

°C °C

Temperature and wet bulb temperature; the

arrow in the lower righthand corner indicates that wet bulb temperature has been chosen

°C

Temperature and mixing ratio; the arrow in the

lower righthand corner indicates that mixing ratio has been chosen (the unit is g/kg or gr/lb).

HMI41 AND HMP42 Operating Manual M210317EN-A

4.3 HOLD-mode

In any of the previously mentioned measurement reading displays, the HOLD

button freezes the display to show the current readings, e.g. RH & T readings:

With MODE or ENTER, the display returns to the normal display mode. If the indicator turns itself off with the automatic power-off function during

°C

hold

the HOLD-mode, it wakes up in the same mode when turned on again. The 'hold'-text is blinking and the indicator can be returned to the normal display mode with any button except ON/OFF.

4.3.1 MIN-mode If you wish to know the minimum readings that have been measured after

power up, press HOLD when the indicator is in the HOLD-mode. The minimum readings of the currently displayed quantities are shown (if the ‘hold’-text is blinking, the HMI41 must first be returned to the normal display mode in order to activate the MIN-mode; see Chapter 4.3 above):

min

With MODE or ENTER, the indicator returns to the normal display mode.

4.3.2 MAX-mode If you wish to know the maximum readings that have been measured after

°C

power up, press HOLD when the indicator is in the MIN-mode. The maximum readings of the currently displayed quantities are shown:

max

The indicator returns to the normal display mode with any button except

°C

ON/OFF.

HMI41 AND HMP42

M210317EN-A Operating Manual

5. CALIBRATION

5.1 How to use the HMP42 calibration adapter

As the HMP42 probe diameter is extremely small, the probe has a special

calibration adapter for inserting the probe into a salt chamber (e.g. in the HMK15 calibrator).

NOTE

Be extremely careful when inserting the probe into the

calibration adapter: do not bend or break it.

The probe is inserted into the adapter with the steel grid on; this protects the

sensor and prevents it from breaking. Unlike other humidity probes, the HMP42 is calibrated with the steel grid on and thus, the probe naturally requires a slightly longer stabilization time (approx. 30 minutes).

Figure 5.1.1 HMI41, HMP42 and calibration accessories

Figure 5.1.2 Insert the probe head into the calibration adapter

HMI41 AND HMP42 Operating Manual M210317EN-A

5.2 Calibration with trimmer potentiometers

5.2.1 Humidity calibration The HMI41 indicator and HMP42 probes are fully calibrated at the factory so

there should be no immediate need for re-calibration. The recommended calibration interval is one year. However, calibration should be performed always when there is a reason to believe that the adjustments have changed.

Humidity calibration of the HMP42 probe is done by adjusting trimmer

potentiometers. The potentiometers are located under a protective plug. The potentiometer marked T (temperature) is for factory use only; DO NOT make any adjustments. To make sure that this potentiometer is not accidentally touched when adjusting the other two, turn the plastic plug aside without removing it completely (see Figure 5.2.1).

For adjusting the potentiometers, use a trimming wrench provided with the

probe, or some other suitable tool, e.g. a ceramic 1.5 mm slot screwdriver.

wet

W D

dry

Figure 5.2.1 Adjusting the trimmer potentiometers

A two point calibration is performed with the HMK15. Calibrator or the probe

can be sent to Vaisala. The probes must always be re-calibrated if the sensor head set is changed.

HMI41 AND HMP42

M210317EN-A Operating Manual

The calibration procedure is as follows (see also the calibrator manual):

• Leave the calibrator and the probe at the calibration site for at least 30

minutes before starting the calibration in order to let the probe temperature stabilize to the room temperature.

• Insert the probe into a measurement hole of the LiCl salt chamber (see

Figure 5.2.2).

Figure 5.2.2 The HMP42 in a salt chamber of the

HMK15 calibrator

• Wait until the humidity reading stabilizes (approx. 30 minutes).

Check the temperature and read the closest humidity value in the calibration table. Adjust the dry end reading with the potentiometer D (dry) in the probe body to correspond to the value given in the calibration table; use a suitable trimming screw wrench (see Figure

5.2.1).

• Insert the thermometer into the 13.5 mm hole of the NaCl salt

chamber and the probe into another hole of the NaCl chamber.

NOTE

When calibrating probes that are being used for long term measurements (over 1 hour) in high humidities (90 - 100 %RH), use the K2SO4 salt as the high end reference.

• Wait until the humidity reading stabilizes. Read the salt chamber

temperature from the thermometer and then the closest humidity value from the calibration table. Adjust the wet end reading with the potentiometer W (wet) to correspond to the value given in the calibration table.

HMI41 AND HMP42 Operating Manual M210317EN-A

Table 5.2 Greenspan’s calibration table

°C

LiCl NaCl K2SO

4 0 * 75.5 98.8 5 * 75.7 98.5 10 * 75.7 98.2 15 * 75.6 97.9 20 11.3 75.5 97.6 25 11.3 75.3 97.3 30 11.3 75.1 97.0 35 11.3 74.9 96.7 40 11.2 74.7 96.4 45 11.2 74.5 96.1 50 11.1 74.4 95.8

* If the LiCl solution is used or stored in temperatures below +18°C, its equilibrium

humidity changes permanently

As the D (dry) and W (wet) adjustments may affect each other, check again the humidity reading in the LiCl salt chamber: insert the probe into the calibration hole and wait until the reading stabilizes. If necessary, repeat the adjustments in both the LiCl and the NaCl (K2SO4) salt chambers until the reading is correct.

5.3 Calibration with HMI41 software commands

Calibration can also be done with the HMI41 software commands by entering

the corrections in the indicator memory with pushbuttons. If only one probe is being used, the HMI41 software calibration is useful. However, when several probes are in use, it is recommended that calibration is done by adjusting the probe potentiometers. Note that when the sensor head set is changed, calibration must always be done by adjusting the potentiometers and it is recommended that the HMI41 is reverted to factory settings by selecting default calibration.

NOTE

If the factory calibration of the HMI41 is changed, the

correction data refers to the calibrated probe only. Therefore, if you change the probe, always revert this data to factory settings by selecting default calibration, or perform a new calibration with the new probe.

HMI41 AND HMP42

M210317EN-A Operating Manual

The calibration procedure is included in the HMI41 setup mode. For entering

the setup mode, first press the ON/OFF button and the following appears:

Td T

P set min max hyst hold Lo bat Hi

% °C °F

°C

°F

Pahg/m

Then release the ON/OFF button and press within 1...2 seconds both ENTER

and MODE buttons until the following text appears on the display:

After a few seconds, the text changes automatically to show the following:

°C

set

Press ENTER eight times until the following text appears:

set

This indicates that no calibration has been selected. In addition to this, there

are five calibration types available. The desired type is selected with buttons ▲ or ▼.

HMI41 AND HMP42 Operating Manual M210317EN-A

All selections are acknowledged with ENTER. In the following, you will find

a list of these calibration options.

Default calibration restores the factory settings of the humidity and temperature calibrations.

set

One point humidity calibration; select this for performing humidity calibration at one point. See Chapter 5.3.1 for further details.

set

Two point humidity calibration; select this for performing humidity calibration at two points. See Chapter 5.3.2 for further details.

set

One point temperature calibration; select this for performing temperature calibration at one point. See Chapter 5.3.3 for further details.

set

Two point temperature calibration; select this for performing temperature calibration at two points. See Chapter 5.3.4 for further details.

set

5.3.1 One point humidity calibration

In one point humidity calibration, one accurate humidity reference is sufficient. However, note that after one point calibration, the humidity reading is most accurate near the reference value. For a better accuracy over the whole range, perform a two point calibration if possible.

Leave the reference instrument (HMK15) and the probe at the calibration site at least 30 minutes so that the probe temperature stabilizes to the room temperature. Start the calibration by inserting the probe to the reference humidity.

In setup mode, press ENTER repeatedly until the following is displayed:

set

HMI41 AND HMP42

M210317EN-A Operating Manual

Then press MODE twice, and the following appears:

set

Press ENTER to activate the one point calibration mode. A message similar to the following appears with the first line blinking:

set

The blinking number indicates the humidity reference value in the HMI41 memory. Check the salt chamber temperature, read the closest humidity value in the calibration table and adjust the display with buttons ▲ and ▼ to correspond to the value given in the table. For example, if the temperature in the calibrator's NaCl salt chamber is 20.5 °C, adjust the value to 75.5 %RH:

set

Each time the button is pressed, the value changes with 0.1 %. If you keep the button pressed, the value changes in a faster mode. Press ENTER and the HMI41 indicator shows the value that the probe is currently measuring, displaying a message similar to the following:

RH %

Wait at least ten minutes for the reading to stabilize and press ENTER to acknowledge the value. Press ENTER again to conclude the one point calibration. If the calibration has been successful, the following message appears:

HMI41 AND HMP42 Operating Manual M210317EN-A

The correction data has now been calculated and stored in the HMI41 memory. The HMI41 returns automatically to the selection of display units, and can be turned off. When the indicator is used as a standard indicator and the correction data differs from the factory settings, an arrow in the upper righthand corner is displayed:

°C

If the message “cal pass” does not appear (instead, some other text may appear, e.g. “too close”, “err offst” or “err gain”), the correction has not been stored in the memory. The error may be due to an incorrect reference value or to measured values that are out of the range.

5.3.2 Two point humidity calibration

In two point humidity calibration, two accurate references (e.g. the HMK15 Calibrator) are needed. Leave the reference instrument and the probe at the calibration site for at least 30 minutes so that the probe temperature stabilizes to the room temperature.

Start the calibration by inserting the probe to the lower reference humidity. In setup mode press ENTER repeatedly until the following is displayed:

set

Then press MODE three times, and the following appears:

set

Press ENTER to activate the two point humidity calibration mode. A message similar to the following appears with the first line blinking:

set

HMI41 AND HMP42

M210317EN-A Operating Manual

The blinking number indicates the value of the lower humidity reference stored in the HMI41 memory. Check the salt chamber temperature, read the closest humidity value in the calibration table and adjust the display with buttons ▲ and ▼ to correspond to the value given in the table. For example, if the temperature of the LiCl salt chamber is 22 °C, adjust the value to

11.3 %RH:

set

Press ENTER, and the HMI41 shows the value that the probe is currently measuring, displaying a message similar to the following:

RH %

Wait at least ten minutes for the reading to stabilize and press ENTER to acknowledge the value. Press ENTER again to conclude the lower point calibration. A message similar to the following appears with the first line blinking:

set

The blinking number indicates the value of the higher humidity reference stored in the HMI41 memory. Insert the probe to the higher reference humidity. Check the salt chamber temperature, read the closest humidity value in the calibration table and adjust the display with buttons ▲ and ▼ to correspond to the value given in the table. For example, if the temperature in the calibrator's NaCl salt chamber is 20.5 °C, adjust the value to 75.5 %RH:

set

Press ENTER and the HMI41 indicator shows the value that the probe is currently measuring, displaying a message similar to the following:

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