DM70 Hand-Held Dewpoint Meter for Spot-Checking

P.O. Box 26, FIN-00421 Helsinki, FINLAND
Tel: +358 9 894 91
Fax: +358 9 8949 2485
DM70 Hand-Held Dewpoint Meter
for Spot-Checking Applications
The Vaisala DRYCAP® HandHeld Dewpoint Meter DM70
offers accurate and fast
measurement for industrial
dewpoint applications, such as
compressed air, metal
treatment and plastics drying.
The Vaisala DRYCAP® Hand-Held
Dewpoint Meter DM70 measures
dewpoint temperature accurately over
a wide measurement range. The probe
may be inserted directly into
pressurized processes, and it responds
rapidly from ambient to process
conditions. The sensor withstands
condensation and fully recovers from
getting wet.
Two probe models
Two models, both with autocalibration, are available. The DMP74A
is for dewpoints between -40...+60 °C.
The DMP74B with Sensor Purge is for
low dewpoints. Sensor Purge heats and
dries the sensor, making the response
from ambient to dry conditions
exceptionally fast. This allows rapid
spot checking measurements in
dewpoints down to -60 °C.
with revolutionary long-term stability.
The result is a long calibration interval
and small maintenance cost.
Vaisala's auto-calibration procedure
works on-line and corrects any dry-end
drift in the calibration curve.
The meter is factory calibrated against
internationally traceable standards and
delivered with a certificate. The DM70
can also be sent to a Vaisala Service
Center for a traceable recalibration.
Designed for industrial spot
checking and field calibration
Two models: accurate measurement
ranges -40...+60 °C (-40…+140 °F)
and -60...+20 °C (-76…+68 °F)
Vaisala DRYCAP® Sensor with
patented autocalibration function
Low maintenance need due to
superior long-term stability
Sensor withstands condensation
Fast response, enhanced by Sensor
Purge option
Easy-to-use user interface
Data can be logged and transferred
to a PC via MI70 Link software
Compact, small and light
NIST traceable (certificate
MI70 Link PC connection
The DM70 has a MI70 Link Windows®
software program for transferring
logged and real time measurement
data from the DM70 to a PC.
Lightweight construction
The DM70 is small and rugged, and
therefore an ideal choice for
demanding applications. The long
battery life provides convenient use in
the field.
Easy-to-use user interface
The DM70 has a versatile and easy-touse, menu-based user interface and a
clear graphical LCD display with datalogger function. It can also be used as a
tool for reading the output of fixed
Vaisala dewpoint transmitters, like the
DMT242, DMT142 and DMP248.
Various display variables
Low maintenance need due
to innovative auto-calibration
The advanced Vaisala DRYCAP®
Sensor provides reliable and highperformance dewpoint measurement
The DM70 displays one to three
parameters at a time, either
numerically or graphically. Several
units can be selected. An analog output
option is also available.
The graphical display helps the user to know
when the dewpoint plateau is reached.
DM70 Accessories:
DSS70A Sampling System and Sampling Cells
DSS70A flow chart
The DSS70A sampling system includes a filter to clean the dirty
sample gas and a needle valve to control the sample flow rate with
the flow meter. A sample pump is used to generate a sample flow
from processes at ambient pressure.
The DSS70A provides a compact solution for
field checking dewpoint where direct
measurement is difficult. Typical applications
for the sampling system are metal treatment
and plastics drying processes.
The DM70 meter is suitable for direct
dewpoint measurements in the process
in a wide temperature and pressure
range. For more demanding
applications, the DM70 can be used
with the Vaisala sampling cell adapters,
or with the Vaisala DRYCAP® Sampling
System DSS70A.
DSS70A portable sampling
The DSS70A is designed to provide
dewpoint sampling flexibility. For
processes at atmospheric pressure, a
battery powered pump is used to
extract a gas sample. For pressurized
processes up to 20 bar, the sample is
measured at process pressure and then
reduced to atmospheric pressure for
venting or re-direction, bypassing the
pump. In all cases, the sample gas
passes through a filter to remove
particulate contamination before
measurement. Flow through the
system is controlled and monitored
with a needle valve and flow meter.
The DSS70A is easily connected to an
appropriate sample point with tubing
(typically 1/4" or 6 mm). The measured
dewpoint must be below ambient
temperature to avoid condensation in
the system. Gas temperatures higher
than +40 °C (+104 °F) should be cooled
with a short PTFE or stainless steel
tube prior to entering the DSS70A.
The DSC74 sampling cell has the
widest variety of connection adapters
to allow several different ways of
installation. The quick connector with
a leak screw allows a very fast
connection for compressed air lines.
Additionally, two thread adapters are
available for the outlet port.
Sampling cells for pressurized
The DM70 can easily be connected to
pressurized processes. In addition to
direct pipeline installation, a variety of
sampling cell options are available for
gas sampling.
The DMT242SC is a basic sampling cell
with only the main sampling cell body.
It has female threaded sample
The DMT242SC2 is a sampling cell
supplied with welded Swagelok
connectors for sampling in a 1/4"
The sampling cells DMT242SC2 (left),
DMT242SC (middle) and DSC74 (right) can
be used to connect the DM70 to pressurized
P.O. Box 26, FIN-00421 Helsinki, FINLAND
Tel: +358 9 894 91
Fax: +358 9 8949 2485
Technical Data
DMP74 dewpoint measurement probes
Measured variables, DMP74A probe
Measured variables, DMP74B probe
Measurement range (typical)
Accuracy -40...+60 °C
Measurement range (typical)
Accuracy -60...+20 °C
-50...+60 °C (-58…+140 °F)
±2 °C (±3.6 °F) (see graph below)
-70...+30 °C (-94…+86 °F)
±2 °C (±3.6 °F) (see graph below)
Response time
flow rate 0.2 m/s, 1 bar pressure, +20 °C (+68 °F)
63% [90%]
0 -> -40 °C Td (32 -> -40 °F Td)
20 s [120 s]
-40 -> 0 °C Td (-40 -> 32 °F Td)
10 s [20 s]
Dewpoint sensor
Vaisala DRYCAP® 180S
Measurement range
-10....+60 °C (+14…+140 °F)
Accuracy at +20 °C (+68 °F)
±0.2 °C (±0.36 °F)
Typical temperature dependence
of electronics
±0.005 °C/°C (±0.005 °F/°F)
Temperature sensor
Pt100 IEC751 1/3 class B
ppm volume concentration
Measurement range (typical)
40...200 000 ppm
Accuracy at +20 °C (+68 °F)
±(7.3 ppm + 8.3% of reading)
Relative humidity
Measurement range
0...100 %RH
Accuracy at +20 °C (+68 °F)
RH < 5 %
±(0.025 %RH + 17.5% of reading)
RH > 5 %
±(0.8 %RH + 2% of reading)
Response time
flow rate 0.2 m/s, 1 bar pressure, +20 °C (+68 °F)
63% [90%]
50 s [340 s]
0 -> -60 °C Td (32 -> -76 °F Td)
-60 -> 0 °C Td (-76 -> 32 °F Td)
10 s [20 s]
Dewpoint sensor
Vaisala DRYCAP® 180M
Measurement range
-10....+60 °C (+14…+140 °F)
Accuracy at +20 °C (+68 °F)
±0.2 °C (±0.36 °F)
Typical temperature dependence
of electronics
±0.005 °C/°C (±0.005 °F/°F)
Temperature sensor
Pt100 IEC751 1/3 class B
ppm volume concentration
Measurement range (typical)
2...40 000 ppm
Accuracy at +20 °C (+68 °F)
< 40 ppm
±(0.5 ppm + 25.4% of reading)
> 40 ppm
±(7.3 ppm + 8.3% of reading)
Measurement environment, both probe models
Indicator general
Sample flow rate
Menu languages
-10....+60 °C (+14…+140 °F)
0...20 bara (0...290 psia)
no effect
General, both probe models
Probe material (wetted parts)
Sensor protection
Mechanical connection
Housing classification
Stainless steel (AISI 316L)
Sintered filter (AISI 316L)
partno: HM47280
G1/2" ISO228-1 thread
with bonded seal ring (U-seal)
IP65 (NEMA 4)
350 g
MI70 measurement indicator
English, French, German, Spanish,
Swedish, Finnish
LCD with backlight
Graphic trend display of any parameter
Character height up to 16 mm
Probe inputs
1 or 2
Power supply
Rechargeable NiMH battery pack
with AC-POWER or 4xAA size alkalines, type IEC LR6
Analog output
0...1 VDC
Output resolution
0.6 mV
Data interface
Datalogging capacity
2700 points
audible alarm function
Operating temperature range
-10...+40 °C (+14…+104 °F)
Operating humidity range
Housing classification
400 g
DMP74 probe + MI70 indicator
= DM70 hand-held dewpoint meter
Housing materials
Storage temperature
Storage humidity
Total weight
ABS/PC blend
-40...+70 °C (-40...+158 °F)
0...100 %RH non-condensing
750 g
wetted parts
carrying case
Case size (W x D x H)
Stainless steel
ABS plastic
430 x 330 x 100 mm
5.5 kg (12 lbs)
Dimensions in mm (inches).
Complies with the EMC standard EN61326-1:1997 + Am1:1998;
Generic Environment.
Battery operation time
Continuous use
Data logging use
48 h typical at +20 °C (+68 °F)
up to 30 days
Sampling cells for pressurized processes
DSS70A sampling system
portable sampling system for field
checking and demanding applications
Connection cables
for DMT242 transmitter
order no: 27160ZZ
for DMP248 transmitter
order no: 27159ZZ
for DMT142 transmitter
order no: 211917ZZ
Analog output cable
order no: 27168ZZ
Windows® software, includes PC connection cable
DSC74 sampling cell technical data
Quick connector fitting
Pressure range
type D or NIP08
0...1 MPag (0...145 psig)
300 g
MI70 indicator
DMP74 probe
DSS70A sampling system
Operating conditions
Operating gases
air, N2 and other non-toxic, inert gases
Dewpoint range
-60 °C...Tamb (-76 °F…Tamb)
Inlet/outlet connection
Operating temperature
ambient temperature
0...+40 °C (32…+104 °F)
process gas temperature
with PTFE tube at +20 °C (+68 °F) max. +200 °C (+392 °F)
with stainless steel tube
specification according to
manufacturer's specification
maximum gas temperature at inlet
+40 °C (+104 °F)
Operating pressure
with pump
0.6...1.2 bara (8.7...17.4 psia)
pump disconnected
0...20 bara (0...290 psia)
Battery operation time for pump
8 h continuous use
battery can be recharged using DM70 charger
7 mm inline filter cartridge 1/4" SWAGELOK SS-4F-7
(spare part order no. 210801)
DSC74, same as
the body of
DMT242SC and
DRYCAP® is a registered trademark of Vaisala.
Specifications subject to change without prior notice.
© Vaisala Oyj