Product guide
27
Humidity and Dew-Point Instruments
Please note: Michell Instruments adopts a continuous development program which sometimes
necessitates specifi cation changes without notice. Please contact us for latest version.
www.michell.com
Precision Manufacturing
Easidew PRO I.S.
Intrinsically Safe Dew-Point Transmitter
The Easidew PRO I.S. is a rugged intrinsically safe 2-wire dew-
point transmitter for trace moisture measurement in liquids and
gases. It is certifi ed for use in IS Class 1 Div 1 Groups A,B,C
and D, Ex II 1G EX ia IIC T4 and I.S. I 1 ABCD T4 (Ta = +60°C)
hazardous area locations.
Highlights
• ±1°C (±1.8°F) accuracy
• Moisture in gases or liquids capability
• 2-wire connection
• Output confi gurable in ppm
V
and ppm
W
moisture content
Simple Operation
The Easidew Pro I.S. is easy to install and operate. It requires
a 12 to 28 V DC supply and provides a linear 4-20 mA signal
representing moisture content.
Moisture in Gases
The output can be confi gured by the customer, using simple
software, to any range within -100 to +20°C (-148 to +68°F)
dp, or 0-3,000 ppm
V
in gases. As the Easidew PRO I.S. responds
to water vapor pressure in the gas sample, it will give the user
an accurate determination of the actual dew-point at pressure
up to 45 MPa (450 barg / 6500 psig). Flow rate is not critical to
measurement accuracy (1 to 5 Nl/min (2.1 to 10.5 scfh)), though
speed of response will be improved by operating at a higher
sample fl ow.
Moisture in Liquids
In addition to its Moisture in Gases capabilities the Easidew
PRO I.S. can be used to monitor moisture in non-polar liquids.
It is factory programmed to provide an output in ppm
w
. This
requires the saturation constants of the liquid to be programmed
into the transmitter either at the factory or by the user, using
the application software, available as a free download from
www.michell.com
Technical Specifi cations
Performance
Measurement range (dp) -100 to +20°C (-148 to +68°F) dew point
Accuracy (dp) ±1°C (±1.8°F) dp (+20 to -60°C (+68 to
-76°F))
±2°C (±3.6°F) dp (-60 to -100°C (-76 to
-148°F))
Response time 5 mins to T95 (dry to wet)
Repeatability 0.5°C (0.9°F) dew point
Electrical output/input
Output signal 4-20 mA (2-wire connection, current source)
User confi gurable over range
Output Dew point, moisture content for ppm
V
, ppm
W
Output range Dew point: -100 to +20°C (-148 to +68°F)
Moisture content in gas: 0-3000 ppm
V
Moisture content in liquid: 0-3000 ppm
W
Supply voltage 12-28 V DC
Load resistance Max 250 @ 12 V; 500 @ 24 V
Current consumption Max 23 mA depending on output signal
Saturation constants
(For moisture in liquids
measurements only)
6-point look-up table for saturation constants
up to 3000 ppm
W
over the temperature range
0 to +50°C.
Saturation constants for 8 common liquids can
be programmed into the Easidew PRO I.S. via
the application software. Alternatively the user
can program saturation constants manually.
Operating conditions
Operating humidity 0–100% RH
Operating temperature -40 to +60°C (-40 to +140°F)
Operating pressure 45 MPa (450 barg / 6500 psig) max
Flow rate 1 to 5 Nl/min (2.1 to 10.5 scfh) mounted in
sampling block; 0 to 10 m/sec (0 to 32.8
fps) direct insertion
Mechanical specifi cation
Hazardous Area
Certifi cates
ATEX - II 1 G Ex ia IIC T4 (-20°C Ta
+70°C)
FM - IS / I / 1 / ABCD / T4 Ta = +70°C
CSA - IS Class 1 Div 1 Groups ABCD T4
IECEx - Ex ia IIC T4 (-20°C Ta +70°C)
Ingress protection IP66 in accordance with standard
BS EN 60529:1992, and NEMA 4 in
protection accordance with standard
NEMA 250-2003
Housing material Stainless steel
Filter 80m sintered guard
HDPE Guard <10m (optional)
Mounting Thread 5/8” - 18 UNF
Weight 1.27kg (2.8lbs)
Electrical connections Screw terminal, M20 x 1.5mm
Fault conditions
(factory programmed)
Condition Output
Sensor fault 23 mA
Under-range dew point 4 mA
Over-range dew point 20 mA
Approved galvanic
isolators
KFD2-CR-EX1.20200
KFD2-CR-EX1.30200
KFD0-CS-EX1.50P
KFD0-CS-EX2.50P
KFD2-STC4-EX1.H
MTL5041, MTL5040
Issue No: Easidew PRO IS_97208_V5_UK_0312