Vaisala HMP45D, HMP45A Technical data

P.O. Box 26, FIN-00421 Helsinki, FINLAND

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Fax: [phone]

HMP45A & HMP45D Relative Humidity and
Temperature Probes; Solar Radiation Shield

Features/Benefi ts

• Vaisala HUMICAP® Humidity and
Temperature Probes HMP45A/D
provide up to 100 %RH with high
accuracy

• Vaisala HUMICAP® Sensor for
excellent accuracy, negligible
hysteresis and long-term stability
in high humidities, and is resistance
to dust and most chemicals.

 e HMP45A and HMP45D humidity
and temperature probes are excellent for
measuring humidity in weather stations.

Versatile probes

 e Vaisala HUMICAP® Humidity and
Temperature Probes HMP45A and
HMP45D are designed for a wide range
of instrumentation (e.g. recorders, data
loggers, laboratory equipment and
weather stations.)

 e probes interface easily, are simple
to service, operate from a wide range
of supply voltages and consume little
power.

 e HMP45A/D is an excellent
solution for measuring humidity in
weather stations. However, the Vaisala
HUMICAP® Humidity and Temperature
Transmitter HMP337, with warmed
sensor head, is a better solution if
condensation continuously disturbs
measurement.

Vaisala HUMICAP® Sensor

 e combined performance of the
Vaisala HUMICAP® Sensor and IP65
(NEMA 4) protected probe provides
accurate and repeatable humidity and
temperature measurements in high
humidity.

Easy fi eld maintenance

Field calibration is easy.  e probe
head containing the sensor and
electronics can be quickly removed
from the probe body, a replacement
installed and the measurements
continued while the other sensor head
is calibrated in a laboratory.

' e DTR503A shield provides protection
from both scattered and direct solar
radiation, and precipitation.

On-site, one-point
calibration

One-point calibration of relative
humidity and temperature can be done
in the  eld using Vaisala HUMICAP®
Humidity Indicator HMI41.

Shield protects sensor

Vaisala Radiation Shield DTR503A is a
naturally ventilated, maintenance-free,
12 plate plastic shield that protects
the humidity and temperature sensors
from both scattered and direct solar
radiation, and precipitation.  e
plastic material in the plates o ers
excellent thermal characteristics and
UV stabilized construction.  e white
outer surface re ects radiation, while
the black inside absorbs accumulated
heat.

 e shield is easy to install and is
suitable for a wide range of applications.
It can be installed on a vertical pole,
horizontal beam, or  at surface.

DTR503A horizontal
beam installation.

• Easy  eld calibration

• Vaisala Solar Radiation Shield
DTR503A

• IP65 (NEMA 4) housing protects
against dust, water spray, and
electromagnetic interference.

• NIST traceable (certi cate included)

Dimensions

Dimensions in mm.

DTR503A
for the HMP45A/D

(437)

(233)

DTR503A pole
mast installation.

HMP45A/D

Pole Mast
diameter

30...60 mm/ 1,2" ... 2,3"

Tel: [phone]

www.vaisala.com

(ø105)

(266)

44 Vaisala Instruments Catalog 2007

Ref. B210641en rev. A

HMP45A, HMP45D, DTR503A

Technical Data

HUMIDITY

General

Operating temperature range -40...+60 °C (-40…+140 °F)
Storage temperature range -40...+80 °C (-40…+176 °F)
Supply voltage 7...35 VDC
Settling time 500 ms
Power consumption <4 mA
Output load >10kohm (to ground)
Weight 350 g (incl. package)
Cable length 3.5 m
Housing material ABS plastic
Housing classi cation (electronics) IP65
Sensor protection:
standard: membrane  lter part no.2787HM

optional: grid part no. 6597
Electromagnetic compatibility Complies with EMC standard
EN61326-1, Generic environment

Relative humidity

HMP45A & HMP45D

Measuring range: 0.8 to 100 %RH
Output scale 0...100 %RH equals 0...1 VDC
Accuracy at +20 °C (+68 °F) (incl. nonlinearity and hysteresis)
against factory references ±1 %RH
 eld calibration against references
±2 %RH (0...90 %RH)
±3 %RH (90...100 %RH)
Typical long-term stability < 1% RH / year
Temperature dependence ±0.05 %RH/ °C (±0.03%RH/°F)
Response time (90% at +20 °C) 10 s with membrane
 lter
Humidity sensor HUMICAP® 180

Temperature

HMP45A

Measurement range -39.2...+60 °C (-39.2…+140°F)
Output scale -40...+60 °C (-40…+140 °F) equals 0...1 VDC
Accuracy at +20 °C (+68 °F) ±0.2 °C (±0.36 °F)

Accuracy over measurement range:

Temperature sensor Pt 1000 IEC 751

HMP45D

Measurement range -40...+60 °C (-40…+140 °F)
Output signal resistive four wire connection
Temperature sensor Pt 100 IEC 751 1/3 Class B

Dimensions

Dimensions in mm.

HMP45A/D connections

HMP45A/D probe

Vaisala Instruments Catalog 2007

Ref. B210641en rev. A

HUMICAP® is a registered trademark of Vaisala.
Speci cations subject to change without prior notice.
©Vaisala Oyj

45