Vaisala HM70 Handheld Humidity Meter Manual

Chapter 2 ________________________________________________________ Product Description

CHAPTER 2

PRODUCT DESCRIPTION

Vaisala HUMICAP

®

Hand-Held Temperature and

Humidity Meter HM70

HM70 consists of two main units: MI70 indicator and

HMP75/HMP76/HMP77 probe. HM70 Hand-held humidity meter incorporates Vaisala's advanced HUMICAP

®

technology which enables reliable and high performance humidity measurement.

HM70 is available with 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.

Vaisala HM70 is delivered with a factory calibration certificate.

Display Parameters

- RH relative humidity (% RH)

- T temperature (

°C/°F)

- T

-

T d

-

d/f

: dewpoint/frostpoint

1)

temperature (

°C/°F)

: dewpoint temperature

2)

a : absolute humidity (g/m

3

(

°C/°F)

/ gr/ft

3

)

- x : mixing ratio (g/kg / gr/lb)

-

T w

: wetbulb temperature (

°C/°F)

-

H

2

O: humid air volume/ dry air volume (ppm)

- pw: water vapour pressure (hPa/ lb/in

2

)

- pws: saturation water vapour pressure(hPa/ lb/in

2

)

- h : enthalpy (kJ/kg / Btu/lb)

-

a w

: water activity

1)

T d/f

shows dewpoint temperature above the freezing point

(0

°°C/32 °°F) and frostpoint temperature T f

(dewpoint over ice) below the freezing point.

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User's Guide ______________________________________________________________________

2)

T d

shows dewpoint over water throughout the entire measurement range.

1

1 Recharger connector

2 Connector ports for probes and cables

3 Power ON/OFF

Port I 2

Figure 1 MI70 indicator

Port II

3

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________________________________________________________________ Product Description

1 Probe filter

2 Probe HMP75/76/77

3 Calibration button under the screw

1

2

3

HMP75 PROBE

Basic probe for relative humidity and temperature measurement

Preheat and chemical purge options available (HMP75B).

HMP76 PROBE

Rugged probe with a long stainless steel shaft. Preheat and chemical purge options available (HMP76B).

HMP77 PROBE

Cable probe for industrial processes up to 180

°C.

Preheat and chemical purge options available (HMP77B).

Figure 2 HMP75, HMP76, and HMP77 probes

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User's Guide ______________________________________________________________________

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