Vaisala HMP247T Technical data

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

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www.vaisala.com

HMP247T Dewpoint Transmitter for High Humidity
Measurements

Features/Benefits

• Designed for high humidity

applications

• Measurement range: -40…+100 °C

• Patented, warm sensor

• Incorporates HUMICAP® Sensor for

excellent accuracy and long-term
stability, negligible hysteresis and
resistance to dust and most
chemicals

• Outer cover provides protection

from rain and direct sunlight

• NIST traceable (certificate included)

Vaisala HUMICAP® Dewpoint Transmitter HMP247T shown with the cover open.

Designed for air intake of power
turbines

The Vaisala HUMICAP® Dewpoint
Transmitter HMP247T was developed
to monitor the air intake of gas and
liquid-fuelled power turbines.

It is ideal for measuring in water vapor
injection applications because the
sensor has been optimized for high
humidity environments by utilizing a
patented, warmed sensing probe. Water
vapor is added to the intake of the
turbine to increase the mass flow which
in turn increases compression and
electrical power output.

Minimal maintenance

Power turbines also require exact water
vapor injection in the chamber to
reduce pollutant emissions. The
HUMICAP® sensor technology is ideal
because of its reliability in the field.
The only suggested scheduled mainte­nance is annual calibration.

Patented, warmed sensor
prevents condensation

The HMP247T provides fast and
reliable dewpoint measurement,
especially under high humidity
conditions where dew would normally

form on the humidity sensor head and
thereby cause errors in measurement.
The patented warmed sensor head
prevents condensation from forming on
the sensor.

Protective enclosure

The HMP247T includes a white,
painted aluminium enclosure with an
installation kit for the probe. The
HMP247 Dewpoint Transmitter is
installed in the aluminium enclosure at
the factory. The HMP247T can be
equipped to be powered with either 24
VDC/VAC or with an internal 110/230
volt power supply unit.

The enclosure consists of an outer
cover that protects the dewpoint
transmitter from direct sun light and
rain. The installation kit protects the
probe from outer water splashes, keeps
the sensor dry, and prevents any parts
that could vibrate loose from entering
the turbine.

Selection of configurations

The HMP247 is available with a
selection of transmitter configurations.
However the suggested configuration
code for turbine applications is
HMP247G1A1A2AA33A2A1B.

The HMP247T can be ordered separately
for installation with the customer’s
existing HMP247 transmitter. The
HMP247 transmitter should have the
following features: parameters for analog
outputs, dewpoint, and mixing ratio;
serial interface RS232C; and no display.

HUMICAP

The HMP240 Series Transmitters are
fitted with the latest version of the
HUMICAP®, a polymer sensor known for
its accuracy, reliability and long-term
stability. The sensor has a high tolerance
for particualte abrasion and chemical
contamination.

Vaisala HUMICAP
Transmitter HMP247

The HMP247 is designed for demanding
industrial humidity measurement
applications with a risk of condensation.

The stainless steel probe head is me-

®

performance

®

Dewpoint

chanically very
durable and
preferred for
most industrial
applications. The
HMP247 probe
head is leak-proof
up to 1 MPa.

Technical Data

Dewpoint temperature

Measurement range -40...+100 °C (-40…+212 °F)
Accuracy: find the intersection of the dewpoint temperature curve and
the dewpoint difference reading (process temperature - dewpoint
temperature) on the x-axis and read the accuracy in dewpoint measure­ment at the y-axis

Response time (90%) at +20 °C (68 °F)
in still air (with sintered filter) 15 s
Sensor HUMICAP® KC sensor

Dimensions

HMP247T Dimensions in mm (inch).

254 (10")

203.2 (8")

76.5 (3")

Outputs

Two analog outputs, 0...20 mA, 4...20 mA,
selectable and scaleable 0...1 V, 0...5 V, 0...10 V
Typical accuracy of analog ±0.05 % full scale
output at +20 °C (+68 °F)
Typical temperature dependence 0.005 % full scale/°C
of analog output
Serial output available RS 232C (Optional RS48S)

General

Connections screw terminals for 0.5 mm

wires (AWG 20), stranded

wires recommended

Operating voltage 24 VDC/VAC (20...28 V)

115/230 VAC

(Must be specified at time of order)

Recommended external load for

current outputs < 500 ohm

0...1 V output > 2 kohm (to ground)

0...5 & 0...10 V outputs > 10 kohm (to ground)
Operating temperature range for -40...+60 °C
electronics

with display cover 0...+50 °C (+32…122 °F)
Storage temperature range -40...+70 °C (-40…158 °F)
Housing material G-AlSi12 (DIN 1725)
Housing classification IP65 (NEMA 4)
Bushing for 7...10 mm diameter cables

(8 x 0.5 mm2 shielded cable)
Humidity sensor protection PPS grid with steel netting
(Ø 13.5 mm)

Complies with EMC standard EN61329-1:1997 + Am1:1998; Industrial
Environment.

2

or

144.53 (5.69")

441.45 (17.38")

101.6 (4")

100 (3.94")

13 (0.51")

164.3 (6.46")

100 (3.94")

193 (7.6")

357.6 (14.08")

488 (19.21")