A precision dew point measurement with remote heads

MBW 473

cable mounted measuring heads
climate chamber validation
ForcefrostTM function



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Flexible measurement options with the 473 chilled mirror.

The determination of dew point by monitoring condensation on a temperature controlled mirror allows a highly accurate (±0.1 °C) measurement. With a typical service life of more than 15 years, MBW chilled mirror hygrometers provide highly accurate and stable measurements over a long service life.

The 473 is a transfer reference standard instrument designed to validate a wide variety of climate chambers and moisture generator systems. 

Optimum Response Injection System (ORIS)

In common with other models in the range, the MBW473 has the ORIS facility, reducing stabilisation time when measuring at low dew point levels.  ORIS uses a pre-programed vapour injection procedure to accelerate the formation of a frost layer on the chilled mirror surface.

A graph showing the improvement in stabilisation time when using ORIS

ForcefrostTM functionFrost - MBW 473

Below 0 °C water may condense as either liquid or solid. This is a particular problem when working at dew points just below 0 °C, and can cause up to a 3 °C  difference in condensation temperature. For correct calculation of relative humidity (rh), the phase of the condensate must be known.  When the Forcefrost function is activated at a user defined temperature the mirror over-cools to ensure that a frost is formed when below 0 °C, and to remove the uncertainty.  




 RP2 measuring head for use with MBW 473

RP2 Measuring Head

To allow optimum placement in working volumes of air, the RP2 head includes a 2-stage thermoelectric cooler (Peltier) element in a compact probe.

Range: -20 to +70 °C

Order code: 103692

 SH2 measuring head for use with MBW 473

SH2 Measuring Head

Ideal for climate chamber validation, humidity generators, engine test cells and on-site calibration projects, this flow-through head assembly includes a variable speed fan that pulls a consistent airflow across the mirror. With the fan removed, the SH2 can be connected to applications using tubing and a standard 6 mm or 1/4 " fitting. 

Range: -30 to +70 °C

Order code: 103693

 Precision temperature measurement for use with MBW 473

Precision Temperature Measurement

Both the RP2 and the SH2 versions of the 473 are supplied with a 4-wire PT1000 Platinum Resistance thermometer (PRT). The temperature probe can be directly connected to the measuring head, or by cable to the 473 back panel, allowing precise temperature measurements to be made for the calculation of rh.


Head Mounted: -20 to +80 °C

Cable mounted: -50 to 100 °C

RP2: Ø3 x 30 mm PRT, 0.5 m cable

SH2:Ø2 x 100 mm PRT, 0.5 and 3 m cables

Transit case for MBW 473

Transit Case

Each 473 is supplied with a robust IP65 transit case for safe transportation to site for calibration projects.


Order Code




Model 473, with SH2 Head assembly on 2 m cable, range -30 to +70°C dew point, 100x 2mm PRT temperature probe with 0.5 and 3m cable. Complete with transport case


Model 473, with RP2 Head assembly on 2 m cable, range -20 to +70°C dew point, 30 x 3mm PRT temperature probe with 0.5 cable. Complete with transport case



473 upgrade factory calibration to ISO17025


Analogue outputs, user programmable, 2 x 4to 20mA or 0 to 10V


0.1% accuracy internal barometric pressure sensor


0.01% accuracy internal barometric pressure sensor


Additional 1 year warranty upgrade (maximum 3 years)

For a complete range of options and accessories, please contact us






Measuring range

Frost/Dew point

-20 to +70 °C

-30 to +70 °C

Relative humidity

+5 to +100 %rh

+2 to +100 %rh

Temperature (head mount PRT)

-20 to +80 °C

-20 to +80 °C

Temperature (cable mount PRT)

-50 to +100 °C

-50 to +100 °C


Frost/Dew point

≤ ± 0.1 °C (-20 to +70 °C), ± 0.2 °C


≤ ± 0.1 °C


Frost/Dew Point

≤ ± 0.05 °C


≤ ± 0.05 °C

Standard Features

Temperature probe

Ø3 x 30 mm PRT, 0.5 m cable

Ø2 x 100 mm PRT, 0.5 and 3 m cables

Digital I/O



5.7" LCD with colour touch screen

Thermoelectric mirror cooling

2-stage with typically 50 °C depression at 20 °C ambient

Mirror temperature sensors

Platinum resistance thermometer (Pt100)

Gas connections

6 mm or 1/4 " Swagelok (SH2 only)

Transport case

Custom fit foam lined Peli 1550

Power cable

2.5 m

Operating instructions


Calibration certificate

Factory calibration: 5 points FP/DP, 3 points temperature. Upgrade to SCS accredited ISO17025 calibration available

Optional Features

Internal barometric pressure sensor

0.1 % or 0.01 % accuracy, 700 to 1200 mbar

Analogue outputs

User programmable, 2x 4 to 20 mA

or 0 to 10 V

Additional Information

Instrument operating conditions

0 to 40 °C, 90 %rh non-condensing

Measuring head operating conditions

-20 to +80 °C, 99 %rh non-condensing

Storage conditions

-20 to +50 °C


In Transport Case


W310 x H155 x D265 mm

W510 x H220 x D450 mm


5 kg

12 kg





Power supply

100 to 120 VAC / 200 to 240 VAC, 50/60 Hz, 100 Watt (auto switching)

All specifications subject to change