Easidew I.S.
Dew-Point Transmitter
User Manual
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97099 Issue 16.6
November 2022
Please ll out the form(s) below for each instrument that has been purchased.
Use this information when contacting Michell Instruments for service purposes.
Product Name
Order Code
Serial Number
Invoice Date
Installation Location
Tag Number
Product Name
Order Code
Serial Number
Invoice Date
Installation Location
Tag Number
Product Name
Order Code
Serial Number
Invoice Date
Installation Location
Tag Number
Easidew I.S.
For Michell Instruments' contact information please go to
www.michell.com
© 2022 Michell Instruments
This document is the property of Michell Instruments Ltd and may not be copied or
otherwise reproduced, communicated in any way to third parties, nor stored in any Data
Processing System without the express written authorization of Michell Instruments Ltd.
Easidew I.S. User Manual
Contents
Safety ................................................................................................................................vi
Electrical Safety ...........................................................................................................vi
Pressure Safety ............................................................................................................vi
Toxic Materials .............................................................................................................vi
Repair and Maintenance ...............................................................................................vi
Calibration ...................................................................................................................vi
Safety Conformity ........................................................................................................vi
Abbreviations .....................................................................................................................vii
Warnings ........................................................................................................................... vii
1 INTRODUCTION ............................................................................................VIII
1.1 Features ..........................................................................................................viii
2 INSTALLATION ..................................................................................................1
2.1 Unpacking the Instrument ................................................................................... 1
2.2 Preparation of the Sensor Cable .......................................................................... 2
2.3 Cable Connection ............................................................................................... 4
2.4 Electrical Schematic ............................................................................................ 4
2.4.1 Electrical Boundaries ..................................................................................... 5
2.5 Transmitter Mounting .......................................................................................... 5
2.5.1 Transmitter Mounting - Sample Block (Optional) .............................................. 6
2.5.2 Transmitter Mounting - Direct Pipeline Connection ........................................... 7
2.5.3 Transmitter Mounting - With Additional Process Connection Adapter ................ 8
3 OPERATION ......................................................................................................9
4 GOOD MEASUREMENT PRACTICE .....................................................................10
5 MAINTENANCE ................................................................................................13
5.1 O-Ring Replacement ......................................................................................... 14
iv 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
Figures
Figure 1 DIN43650 Transmitter Unpacking Method ....................................................2
Figure 2 Connector Terminal Block Removal ..............................................................3
Figure 3 Bare Wires .................................................................................................3
Figure 4 Crimped Wires ...........................................................................................3
Figure 5 Cut to 5mm ...............................................................................................4
Figure 6 Connection to Connector Terminal Block .......................................................4
Figure 7 Wiring Connections .....................................................................................4
Figure 8 Connector Installation .................................................................................5
Figure 9 Electrical Connections .................................................................................5
Figure 10 Transmitter Mounting ..................................................................................7
Figure 11 Transmitter Mounting - Pipe or Duct.............................................................8
Figure 12 Transmitter Mounting with Adapter .............................................................9
Figure 13 Installation Location .................................................................................10
Figure 14 Indication of Dead Space ..........................................................................10
Figure 15 Material Permeability Comparison ..............................................................11
Figure 16 Replacement of HDPE Guard .....................................................................14
Figure 17 Dimensions .............................................................................................18
Michell Instruments v
Easidew I.S. User Manual
Appendices
Appendix A Technical Specications ............................................................................. 17
A.1 Dimensions .................................................................................18
Appendix B System Drawings ....................................................................................... 20
B.1 Baseefa Approved System Drawing ...............................................20
B.2 QPS Approved System Drawing .....................................................21
Appendix C Hazardous Area Certication ......................................................................23
C.1 Product Standards ....................................................................... 23
C.2 Product Certication ....................................................................23
C.3 Global Certicates/Approvals ........................................................23
C.4 Terminal Parameters ....................................................................24
C.5 Special Conditions of Use .............................................................24
C.6 Maintenance and Installation ........................................................ 24
Appendix D Quality, Recycling & Warranty Information ................................................... 26
Appendix E Return Document & Decontamination Declaration ........................................ 28
vi 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
Safety
The manufacturer has designed this equipment to be safe when operated using the procedures
detailed in this manual. The user must not use this equipment for any other purpose than that
stated. Do not apply values greater than the maximum value stated.
This manual contains operating and safety instructions, which must be followed to ensure the safe
operation and to maintain the equipment in a safe condition. The safety instructions are either
warnings or cautions issued to protect the user and the equipment from injury or damage. Use
competent personnel using good engineering practice for all procedures in this manual.
Electrical Safety
The instrument is designed to be completely safe when used with options and accessories supplied
by the manufacturer for use with the instrument.
Pressure Safety
DO NOT permit pressures greater than the safe working pressure to be applied to the instrument. The
specied safe working pressure is 45 MPa (450 barg/6500 psig). Refer to the Technical Specications
in Appendix A.
Toxic Materials
The use of hazardous materials in the construction of this instrument has been minimized. During
normal operation it is not possible for the user to come into contact with any hazardous substance
which might be employed in the construction of the instrument. Care should, however, be exercised
during maintenance and the disposal of certain parts.
Repair and Maintenance
The instrument must be maintained either by the manufacturer or an accredited service agent. Refer
to www.michell.com for details of Michell Instruments’ worldwide oces contact information.
Calibration
The recommended calibration interval for this instrument is 12 months unless it is to be used in a
mission-critical application or in a dirty or contaminated environment in which case the calibration
interval should be reduced accordingly. The instrument should be returned to the manufacturer,
Michell Instruments Ltd., or one of their accredited service agents for re-calibration.
Safety Conformity
This product meets the essential protection requirements of the relevant UK, EU and US standards
and directives. Further details of applied standards may be found in the Technical Specications in
Appendix A.
Michell Instruments vii
Abbreviations
The following abbreviations are used in this manual:
barg pressure unit (=100 kP or 0.987 atm) (bar gauge)
°C degrees Celsius
°F degrees Fahrenheit
DC direct current
dp dew point
fps feet per second
ft-lbs feet per pounds
g grams
lbs/in pounds per inch
µm micrometer
m/sec meters per second
mA milliampere
max maximum
mm millimetres
MPa megapascal
Nl/min normal liters per minute
Nm Newton meter
oz ounces
ppm
V
psig pounds per square inch
RH relative humidity
scfh standard cubic feet per hour
V Volts
Ω Ohms
ø diameter
“ inch(es)
Easidew I.S. User Manual
parts per million by volume
Warnings
The following general warning listed below is applicable to this instrument. It is repeated
in the text in the appropriate locations.
Where this hazard warning symbol appears in the following
sections it is used to indicate areas where potentially hazardous
operations need to be carried out.
viii 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
1 INTRODUCTION
The Easidew I.S. dew-point transmitter has been manufactured, tested and calibrated
to the highest available standards and should be in perfect working order, ready for
installation into a gas measurement application. If, after reading this manual, there
are any questions about the instrument or how to install and operate it, please contact
a Michell representative. Refer to www.michell.com for details of Michell Instruments’
worldwide oces contact information.
This manual covers the following Easidew I.S. (Intrinsically Safe) dew-point products:
Easidew I.S. with G 1/2” BSP thread
Easidew I.S. with 3/4” UNF thread
Easidew I.S. with 5/8” UNF thread
1.1 Features
INTRODUCTION
The Easidew I.S. dew-point transmitter is a continuous, on-line, 4...20 mA transmitter
for the measurement of dew-point temperature or moisture content in air and other
non-corrosive gases. It is designed specically for use within Zone 0, 1 and 2 hazardous
areas.
The key features are:
• IECEx, QPS, ATEX, UKCA certied transmitter for use in hazardous areas
• G1/2” BSP, 3/4” or 5/8” UNF process connection
• Dew-point or ppmV moisture content
• 2-wire loop powered connection
• Rugged 316 stainless steel IP66 construction
• Measurement ranges -100...+20°Cdp (-148...+68°Fdp)
-110...+20°Cdp (-166...+68°Fdp)
• Accuracy ±2°Cdp
• Calibration Certicate (NPL, NIST)
Michell Instruments 1
INSTALLATION
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2 INSTALLATION
2.1 Unpacking the Transmitter
On removing the transmitter from the box, please check that all the following standard
components are included:
• Easidew Transmitter
• Certicate of Calibration
• Electrical Connector (DIN 43650 models only)
Easidew I.S. User Manual
Figure 1
DIN43650 Transmitter Unpacking Method
The Transmitter will also be supplied with a process seal, which will be tted to the
unit. Depending on the version, this will either be a bonded seal (5/8” or G1/2” thread
versions) or an o-ring seal (3/4” thread versions).
The transmitter sensing element is protected while in transit by a blue plastic cover
containing a small desiccant capsule. The cover should be removed before operation
but should be retained in case required for return shipping.
Depending on the model, the transmitter may come with the electrical connector tted
to protect the transmitter pins during transit. Keep the connector in a safe place until
ready to wire up the sensor.
2 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
2.2 Preparation of the Sensor Cable
The sensor cable is NOT supplied as standard. A cable can be obtained by contacting
your local distributor or Michell Instruments (see www.michell.com for details).
The crimps supplied must be tted onto any cable installed
into the connector in order to comply with Hazardous Area
Certication of the product.
If making a cable assembly it is important that the cable is correctly terminated. See
Figures 3 to 6
Cable connection to the Easidew I.S. transmitter is made via the removable connector.
Removing the central screw enables the connector terminal block to be removed from
the outer housing by using a small screwdriver to prise it clear.
.
INSTALLATION
O-ring
and washer
Figure 2
Caution: When removing the central screw ensure that the
small sealing O-ring and the washer are retained on the screw
NOTE:
crimps should be applied such that there is no possibility of a conductor
strand of a core becoming free (see
Figure 3
to
Figure 6
Connector Terminal Block Removal
and are present during re-installation.
shown below, should be followed in detail. The
Figure 4)
.
Figure 3
Bare Wires
Figure 4
Crimped Wires
Michell Instruments 3
INSTALLATION
When the crimp is made it should have a minimum of 2 positions of crimping. After the
crimp is made it should be trimmed to a length of 5mm (see
are installed into the connector terminal block ensure they are fully inserted, as shown
in
Figure 6
Easidew I.S. User Manual
, before tightening the terminal clamping screw.
3 4
Figure 5)
1
. When the crimps
When all wire connections are made, ensure that there is a minimum clearance distance
and a minimum creepage distance in air of 2mm (0.8”) between each terminal.
For the transmitter to work properly, and to achieve maximum performance, the sensor
cable must be connected to the sensor connector as shown in the drawing below.
Note: The drawing below shows the identity of the connector terminals and
wiring connections of the cable manufactured by Michell Instruments.
10
Figure 5
mm
Cut to 5mm
Figure 6
2
Connection to Connector
Terminal Block
GN
RD
BL
GREEN - 4-20 mA
RED + POWER
BLUE - SCREEN
BRAID
GREEN - 4-20 mA
(SOURCE)
BLUE - SCREEN
RED + POWER
SCALE 2:1
SHORT
AS POSSIBLE
+POWER
GREEN
SIGNAL (SOURCE)
1
3
RED
2
VIEW ON REAR
OF CONNECTOR
BLUE
GND
4
Figure 7
BRAID
SCREEN
GREEN
YELLOW
BLUE
RED
Wiring Connections
Always connect the 4...20 mA return signal to a suitable
load (see
Figure 7)
before the power is applied. Without this
connection, the transmitter may be damaged if allowed to
operate for prolonged periods.
4 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
2.3 Cable Connection
When installing the connector, and to ensure that full ingress protection is achieved, the
securing screw (with the O-ring and washer) must be tightened to a minimum torque
setting of 3.4 Nm (2.5 ft-lbs). The sensor cable used must be a minimum diameter of
4.6mm (0.2”).
INSTALLATION
O-ring
and washer
2.4 Electrical Schematic
NOTE: The screen/shield should be connected for maximum performance
and to avoid interference.
GALVANIC ISOLATION INTERFACE
HAZARDOUS AREA
TRANSMITTER VERSION
DEW-POINT
TRANSMITTER
CERTIFICATION No’s:
Baseefa06ATEX0330X
IECEx BAS 06.0090X
TERMINAL NUMBER
EASIDEW I.S.
3
1
(+)
(RETURN)
Figure 8
Connector Installation
SAFE AREA
KFD2-STC4-Ex1 H
KFD0-CS-Ex2.50p
KFD2-CR-Ex1.20200
KFD2-CR-Ex1.30200
(+)
KFD0-CS-Ex1.50P
(-)
MTL5041
MTL5040
MTL5541
+
-
4-20 mA
LOAD
+VS (20 - 35 V DC)
VS -
Figure 9
Electrical Connections
Michell Instruments 5
INSTALLATION
2.5 Transmitter Mounting
Prior to installation of the transmitter, unscrew and remove the black, green or blue
plastic cover and retain for future use. Take care to prevent any contamination of
the sensor before installation (handle the transmitter by the main body only,
avoiding contact with the sensor guard).
The Easidew I.S. can be mounted either into a ow-through sensor sampling block
(optional) or directly into a pipe or duct. It can be operated at pressures of up to 45 MPa
(450 barg / 6500 psig) when tted with the bonded seal or O-ring provided.
The recommended gas ow rate, when mounted in the optional sampling block, is 1 to
5 Nl/min (2.1 to 10.6 scfh). However, for direct insertion applications, gas ow can be
from static to 10 m/sec (32.8 fps).
NOTE: Pass the seal over the mounting thread and assemble into the sampling
location, by hand, using the wrench ats only. DO NOT grip and twist the
sensor cover when installing the sensor.
Easidew I.S. User Manual
When installed, fully tighten using a wrench until the seal is fully compressed and to the
following torque settings:
• G 1/2” BSP 56 Nm (41.3 ft-lbs)
• 3/4” - 16 UNF 40 Nm (29.5 ft-lbs)
• 5/8” - 18 UNF 30.5 Nm (22.5 ft-lbs)
6 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
2.5.1 Transmitter Mounting - Sample Block (Optional)
The following procedure must be carried out by a qualied
installation engineer.
To mount the transmitter into the sensor block (preferred method), proceed as follows,
refer to
1. Ensure that the green, blue or black protective cover (2), and its
2. G 1/2” and 5/8” Versions - Ensure that the bonded seal (2) is over the
Figure 12.
desiccant capsule (2a), have been removed from the tip of the
transmitter.
threaded part of the transmitter body.
3/4” Version - Ensure the O-ring is fully seated in the recess.
INSTALLATION
Under no circumstances should the sensor guard be handled
with the ngers.
3. Screw the transmitter (1) into the sample block (3) and tighten to the
appropriate torque setting (see Section 2.5). NOTE: Use the ats of
the hexagonal nut and not the sensor body.
4. Fit the transmitter cable/connector assembly to the plug located on the
base of the transmitter and tighten the xing screw (see Section 2.3).
2
2a
4
1
3
4
Figure 10
Transmitter Mounting
Michell Instruments 7
INSTALLATION
14
15
16
17
18
18
20
21
22
23
2
3
4
5
6
7
8
9
10
11
Easidew I.S. User Manual
2.5.2 Transmitter Mounting - Direct Pipeline Connection
The transmitter may be directly mounted into a pipe or duct as shown in
Figure 13.
Caution: Do not mount the transmitter too close to the bottom
of a bend where any condensate in the pipeline might collect
and saturate the probe.
The pipe or duct will require a thread to match the transmitter body thread. Fixing
dimensions are shown in
Figure 13.
For circular pipework, to ensure the integrity of a
gas tight seal, a mounting ange will be required on the pipework in order to provide a
at surface to seal against.
The following procedure must be carried out by competent
personnel.
1. Ensure that the protective cover (and its desiccant capsule) has
been removed from the tip of the transmitter.
WARNING: Under no circumstances should the sensor guard
be handled with the ngers.
2. G 1/2” and 5/8” Versions - Ensure that the bonded seal (2) is over the
threaded part of the transmitter body.
3/4” Version - Ensure the O-ring is fully seated in the recess.
3. Screw the transmitter (3) into the pipe (1). Tighten enough to obtain
a gas tight seal. NOTE: Do not overtighten or the thread on the
pipework may be stripped.
Optional
1
2
3
display
(available
on request)
1
Optional
cable
2
48mm
3
(1.9”)
Figure 11
8 97099 Issue 16.6, November 2022
Transmitter Mounting - Pipe or Duct
(available
on request)
Easidew I.S. User Manual
2.5.3 Transmitter Mounting - With Additional Process Connection Adapter
Applicable to the Easidew I.S. 5/8” Version ONLY
INSTALLATION
!
To mount the adapter into the transmitter, proceed as follows (see
1. Ensure that the protective cover (2), and its desiccant capsule (2a), have
been removed from the tip of the transmitter.
2. Fit the bonded seal (3) over the threaded part of the transmitter body.
3. Screw the adapter (4) onto the threaded part of the transmitter and tighten
to 30.5 Nm (22.5 ft-lbs). NOTE: Use the ats of the hexagonal nut and
not the sensor body.
!
4. Screw the transmitter (1) with its seal (3) and adapter (4) into the sample
block (see Section 2.5.1) or pipeline (see Section 2.5.2) and fully tighten
using a wrench until the seal is fully compressed and to the following torque
settings:
The following procedure must be carried out by a qualied
installation engineer.
Figure 14)
WARNING: Under no circumstances should the sensor guard be
handled with the ngers.
:
G 1/2” BSP 56 Nm (41.3 ft-lbs)
3/4” - 16 UNF ` 40 Nm (29.5 ft-lbs)
1/2” NPT Use a suitable sealant e.g. PTFE tape using
correct taping procedures
NOTE: Use the ats of the hexagonal nut and not the sensor body.
2
2a
4
1
3
Figure 12
Transmitter Mounting with Adapter
Michell Instruments 9
OPERATION
3 OPERATION
Operation is very simple, assuming the following installation techniques are adhered to:
Sampling Hints
Be Sure the Sample is Representative of the Gas Under Test:
The sample point should be as close to the critical measurement point as possible. Also,
never sample from the bottom of a pipe as entrained liquids may be drawn into the
sensing element.
Easidew I.S. User Manual
Figure 13
Minimize Dead Space in Sample Lines:
Dead space causes moisture entrapment points, increased system response times and
measurement errors, as a result of the trapped moisture being released into the passing
sample gas and causing an increase in partial vapor pressure.
Figure 14
Remove Any Particulate Matter or Oil from the Gas Sample:
Particulate matter at high velocity can damage the sensing element and similarly, at
low velocity, they may ‘blind’ the sensing element and reduce its response speed. If
particulate, such as degraded desiccant, pipe scale or rust is present in the sample gas,
use an in-line lter, as a minimum level of protection. For more demanding applications
Michell Instruments oers a range of sampling systems (for more information contact
www.michell.com).
Installation Location
Deadspace
Indication of Dead Space
Use High Quality Sample Tube and Fittings:
Michell Instruments recommends that, wherever possible, stainless steel tubing and
ttings should be used. This is particularly important at low dew points since other
materials have hygroscopic characteristics and adsorb moisture on the tube walls,
slowing down response and, in extreme circumstances, giving false readings. For
temporary applications, or where stainless steel tubing is not practical, use high quality
thick walled PTFE tubing.
Position Transmitter away from Heat Source:
It is recommended, as good instrumentation practice, that the transmitter is placed
away from any heat source to avoid adsorption/desorption.
10 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
4 GOOD MEASUREMENT PRACTICE
Ensuring reliable and accurate moisture measurements requires the correct sampling
techniques, and a basic understanding of how water vapor behaves. This section aims
to explain the common mistakes and how to avoid them.
Sampling Materials – Permeation and Diusion
All materials are permeable to water vapor since water molecules are extremely small
compared to the structure of solids, even including the crystalline structure of metals.
The graph above demonstrates this eect by showing the increase in dew point
temperature seen when passing very dry gas through tubing of dierent materials,
where the exterior of the tubing is in the ambient environment.
- 20
- 30
GOOD MEASUREMENT PRACTICE
- 40
- 50
Dew point (ºC)
- 60
- 70
Figure 15
nickel
stainless steel
1 2 3 4 5
Time (hours)
Material Permeability Comparison
nylon
copper
polyethylene
PTFE
What this demonstrates is the dramatic eect that dierent tubing materials have on
the humidity levels of a gas passed through them. Many materials contain moisture
as part of their structure and when these are used as tubing for a dry gas the gas
will absorb some of the moisture. Always avoid using organic materials (e.g. rubber),
materials containing salts and anything which has small pores which can easily trap
moisture (e.g. nylon).
As well as trapping moisture, porous sampling materials will also allow moisture vapor
to ingress into the sample line from outside. This eect is called diusion and occurs
when the partial water vapor pressure exerted on the outside of a sample tube is
higher than on the inside. Remember that water molecules are very small so in this
case the term ‘porous’ applies to materials that would be considered impermeable in
an everyday sense – such as polyethylene or PTFE. Stainless steel and other metals
can be considered as practically impermeable and it is surface nish of pipework that
becomes the dominant factor. Electropolished stainless steel gives the best results over
the shortest time period.
Take into consideration the gas you are measuring, and then choose materials appropriate
to the results you need. The eects of diusion or moisture trapped in materials are
more signicant when measuring very dry gases than when measuring a sample with a
high level of humidity.
Michell Instruments 11
GOOD MEASUREMENT PRACTICE
Temperature and Pressure eects
As the temperature or pressure of the environment uctuates, water molecules are
adsorbed and desorbed from the internal surfaces of the sample tubing, causing small
uctuations in the measured dew point.
Easidew I.S. User Manual
Adsorption
solid to the surface of a material, creating a lm. The rate of adsorption is increased at
higher pressures and lower temperatures.
Desorption
constant environmental conditions, an adsorbed substance will remain on a surface
almost indenitely. However, as the temperature rises, so does the likelihood of
desorption occurring.
Ensuring the temperature of the sampling components is kept at consistent levels is
important to prevent temperature uctuation (i.e. through diurnal changes) continually
varying the rates of adsorption and desorption. This eect will manifest through a
measured value which increases during the day (as desorption peaks), then decreasing
at night as more moisture is adsorbed into the sampling equipment.
is the adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved
is the release of a substance from or through the surface of a material. In
If temperatures drop below the sample dew point, water may condense in sample
tubing and aect the accuracy of measurements.
Maintaining the temperature of the sample system tubing above the dew point of the
sample is vital to prevent condensation. Any condensation invalidates the sampling
process as it reduces the water vapor content of the gas being measured. Condensed
liquid can also alter the humidity elsewhere by dripping or running to other locations
where it may re-evaporate.
Although ambient pressure does not change drastically in a single location, the gas
sample pressure does need to be kept constant to avoid inconsistencies introduced
by adsorption or desorption. The integrity of all connections is also an important
consideration, especially when sampling low dew points at an elevated pressure. If
a small leak occurs in a high-pressure line, gas will leak out; however, vortices at the
leak point and a negative vapor pressure dierential will also allow water vapor to
contaminate the ow.
Theoretically ow rate has no direct eect on the measured moisture content, but
in practice it can have unanticipated eects on response speed and accuracy. An
inadequate ow rate may:
12 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
• Accentuate adsorption and desorption eects on the gas passing through
the sampling system.
• Allow pockets of wet gas to remain undisturbed in a complex sampling
system, which will then gradually be released into the sample ow.
• Increase the chance of contamination from back diusion. Ambient air
that is wetter than the sample can ow from the exhaust back into the
system. A longer exhaust tube can help alleviate this problem.
• Slow the response of the sensor to changes in moisture content.
An excessively high ow rate can:
• Introduce back pressure, causing slower response times and unpredictable
changes in dew point
• Result in a reduction in depression capabilities in chilled mirror instruments
by having a cooling eect on the mirror. This is most apparent with gases
that have a high thermal conductivity such as hydrogen and helium.
GOOD MEASUREMENT PRACTICE
System design for fastest response times
The more complicated the sample system, the more areas there are for trapped moisture
to hide. The key pitfalls to look out for here are the length of the sample tubing and
dead volumes.
The sample point should always be as close as possible to the critical measurement
point to obtain a truly representative measurement. The length of the sample line to the
sensor or instrument should be as short as possible. Interconnection points and valves
trap moisture, so using the simplest sampling arrangement possible will reduce the time
it takes for the sample system to dry out when purged with dry gas.
Over a long tubing run, water will inevitably migrate into any line, and the eects of
adsorption and desorption will become more apparent.
Dead volumes (areas which are not in a direct ow path) in sample lines, hold onto
water molecules which are slowly released into the passing gas. This results in increased
purge and response times, and wetter than expected readings. Hygroscopic materials
in lters, valves (e.g. rubber from pressure regulators) or any other parts of the system
can also trap moisture.
Plan your sampling system to ensure that the sample tap point and the measurement
point are as close as possible to avoid long runs of tubing and dead volumes.
Filtration
All trace moisture measurement instruments and sensors are by their nature sensitive
devices. Many processes contain dust, dirt or liquid droplets. Particulate lters are used
for removing dirt, rust, scale and any other solids that may be in a sample stream.
For protection against liquids, a coalescing or membrane lter should be used. The
membrane provides protection from liquid droplets and can even stop ow to the
analyser completely when a large slug of liquid is encountered, saving the sensor from
potentially irreparable damage.
Michell Instruments 13
MAINTENANCE
r
5 MAINTENANCE
Calibration
Routine maintenance of the Easidew I.S. is conned to regular re-calibration by
exposure of the transmitter to sample gases of known moisture content to ensure that
the stated accuracy is maintained. Calibration services traceable to the UK
Physical Laboratory
(NIST) are provided by Michell Instruments.
Michell Instruments oers a variety of re-calibration and service exchange schemes to
suit specic needs. A Michell representative can provide detailed, custom advice (refer to
www.michell.com for details of Michell Instruments’ worldwide oces contact information).
Easidew I.S. User Manual
National
(NPL) and the US
The following procedure must be carried out by a qualied
National Institute of Standards and Technology
installation engineer.
Sensor Guard Replacement
The sensor is supplied with either a white HDPE or a stainless steel guard. The method
of replacement is the same for both types.
HDPE Guard
The HDPE guard provides <10μm protection to the dew-point sensor. It is designed
to show any contamination and the guard should be changed if the surface becomes
discolored.
When replacing the guard, care should be taken to handle the guard by the bottom part
only. Replacement guards (EA2-HDPE) – a pack of 10 – can be obtained by contacting
Michell Instruments (www.michell.com) or your local distributor.
HANDLE,
USING
GLOVES, BY
BLACK PART
ON LY
E
n
e
H
m
C
u
I
r
6
t
s
0
M
n
9
I
0
Figure 16
Replacement of HDPE Guard
Stainless Steel Guard
The stainless steel guard provides <80μm protection to the dew-point sensor. Please
change the guard if contamination is apparent.
When replacing the guard, care should be taken to handle the guard by the bottom part
only. A replacement guard (SSG) can be obtained by contacting Michell Instruments
(www.michell.com) or your local distributor.
14 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
Bonded Seal
If the installed bonded seal gets damaged or lost, a pack of 5 replacement bonded seals
(1/2-BS (for G 1/2 -BSP) or 5/8-BS (for 5/8” -18 UNF)) can be obtained by contacting
Michell Instruments, or your local distributor.
5.1 O-Ring Replacement
If the installed O-ring gets damaged or lost, a pack of 5 replacement O-rings (3/4OR (for 3/4” - 16 UNF)) can be obtained by contacting Michell Instruments, or your local
distributor.
1. Identify the O-ring to be removed, as shown below.
MAINTENANCE
Do not touch the lter with bare hands
BS116 (3/4” x 3/32”) viton,
75 shore
2. Carefully slide tweezers, thin bladed screwdriver or a blunt needle under
the outer edge of the O-ring. NOTE: Take care not to scratch any of
the surfaces of the surrounding metal component.
3. Move the tool around the circumference to assist the extraction process.
Slide the O-ring clear of the thread and lter.
4. Make sure the groove has no scratches and is free from grease, dirt
or debris. Slide the new O-ring over the lter and thread and into the
groove. NOTE: Do not touch the lter with bare hands.
Michell Instruments 15
APPENDIX A
Easidew I.S. User Manual
Appendix A
Technical Specications
16 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
Appendix A Technical Specications
Performance
APPENDIX A
Measurement Range
(dew point)
Accuracy (dew point) ±2°Cdp (±3.6°Fdp)
Repeatability 0.5°Cdp (0.9°Fdp)
Response Time 5 mins to T95 (dry to wet)
Calibration 13-point calibration with traceable 7-point calibration certicate
-100...+20°Cdp (-148...+68°Fdp)
-110...+20°Cdp (-166...+68°Fdp)
Electrical Specications
Output Signal
Output Dew point or moisture content for ppm
Analog Output Scaled
Range
Supply Voltage 12...28 V DC
Load Resistance
Current Consumption 20 mA max
CE Marked Certied
4...20 mA (2-wire connection current source)
User-congurable over range
V
Dew point: -100...+20ºC (-148...+68ºF) OR
Moisture content in gas: 0 - 3000 ppm
Non-standard available upon request
Max 250 Ω @ 12 V
(500 Ω @ 24 V)
V
Operating Specications
Operating Temperature -40...+60ºC (-40...+140ºF)
45 MPa (450 barg / 6500 psig) max
Operating Pressure
Compensated
Temperature Range:
Storage Temperature: -40...+60ºC (-40...+140ºF)
Flow Rate
Qualied over-pressure rating: (2 x operating pressure)
90 MPa (900 barg / 13053 psig)
-20...+50°C (-4...+122ºF)
NOTE: The transmitter accuracy statement is only valid for the
temperature range: -20...+50°C (-4...+122ºF)
1...5 Nl/min (2.1...10.6 scfh) mounted in standard sampling block
0...10 m/sec (0...32.8 fps) direct insertion
Mechanical Specications
Ingress Protection
Housing Material 316 stainless steel
Dimensions Transmitter plus connector: L=132mm x ø 45mm (5.19” x ø 1.77”)
Sensor Guard
Process Connection &
Material
Weight 150g (5.29oz)
Interchangeability Fully interchangeable transmitter
Electrical Connection Hirschmann GDS series (DIN 4350-C)
Diagnostic Conditions
(factory programmed)
IP66 in accordance with standard BS EN60529:1992
NEMA 4 in protection accordance with standard NEMA 250-2003
Standard: HDPE Guard < 10µm
Optional: 316 stainless steel sintered guard < 80µm
G 1/2” BSP; 3/4” - 16 UNF; 5/8” - 18 UNF
Material - 316 stainless steel
Condition
Sensor fault
Under-range dew point
Over-range dew point
Output
23 mA
4 mA
20 mA
Michell Instruments 17
APPENDIX A
Easidew I.S. User Manual
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
Hazardous Area Certication
Certication Codes * See Appendix C
*
The end user has a responsibility to ensure that when installed in the Hazardous Area, the system is compliant
with relevant local and international installation Standards for the use of equipment in explosive atmospheres.
A.1 Dimensions
SENSOR
10mm
(0.39”)
132mm
(5.19”)
ø27mm
(1.06”)
10mm
(0.39”)
46mm
(1.81”)
G1/2” BSP
G1/2” BSP Bonded Seal
ø28.65 x 2.61mm
(ø1.12 x 0.10”)
27mm
(1.06”)
A/F
45mm
(1.77”)
G1/2” Process Connection
SENSOR
10mm
(0.39”)
132mm
(5.19”)
ø27mm
(1.06”)
46mm
(1.81”)
3/4” UNF
10mm
(0.39”)
3/4” - 16 UNF O-Ring
ø18.72 x 2.62mm
(ø0.75 x 0.09”)
27mm
(1.06”)
A/F
45mm
(1.77”)
3/4” Process Connection
SENSOR
10mm
(0.39”)
132mm
(5.19”)
ø27mm
(1.06”)
46mm
(1.81”)
5/8” UNF
10mm
(0.39”)
5/8” Process Connection
5/8” - 18 UNF Bonded Seal
ø25.4 x 2mm
(ø1 x 0.07”)
27mm
(1.06”)
A/F
45mm
(1.77”)
Figure 17
Dimensions
18 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
APPENDIX B
Appendix B
System Drawings
Michell Instruments 19
APPENDIX B
Appendix B System Drawings
B.1 Baseefa Approved System Drawing
Easidew I.S. User Manual
20 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
10/03/06
MSB
Ex90385QPS
SHEET 1 OF 1
NTS
SCALE
SIGN
A3
DATE
MOD. No.ISSUE
DRAWING NUMBER
TOLERANCES:
UNLESS OTHERWISE STATED
FINISH
DIMENSIONS:
MATERIAL
TITLE
USED ON
APPROVEDCHECKED
DATEDATE
DRAWN
DATE
MICHELL INSTRUMENTS LTD. 01/11/05 DOF03
mm
DRAWING
UNITS
THIS DOCUMENT IS THE PROPERTY OF MICHELL INSTRUMENTS LTD.
AND MUST NOT BE COPIED NOR DISCLOSED TO A THIRD PARTY
WITHOUT THE CONSENT OF MICHELL INSTRUMENTS.
EASIDEW I.S. & EASIDEW PRO I.S.
DEWPOINT TRANSMITTER
SYSTEM DRAWIN. QPS
3rd ANGLE
PROJECTION
MICHELL INSTRUMENTS LTD. CAMBRIDGE ©
ANGLES: ±0.5°
HOLE Ø:
+0.1
-0.0
0 DEC. PLACE: ± 0.
5
1 DEC. PLACE: ± 0.2
2 DEC. PLACE: ± 0.1
03 CERT ISS 16/06/08 I MA
4 Inches
100mm
04 CERT ISS 25/03/09 IMA
05 CERT ISS 15/06/09 I MA
06 11081 06/04/11 IMA
07 13395 16/12/13 IMA
08 02/11/17 IMA
Pi increased
09 QPS 30/06/21 IMA
Approved
Barrier
HAZARDOUS LOCATION
CLASS I, DIVISION 1,
Gps A,B,C, & D
CLASS I, ZONE 0
AEx ia IIC T4 Ga
Ex ia IIC T4 Ga
Tamb+70°C
NON-HAZARDOUS LOCATION
VS -
LOAD
4/20mA
+
-
(+)
(-)
EASIDEW
DEWPOINT
TRANSMITTER
Vmax = 28V
Imax = 93mA
Pmax = 820mW
Ci = 37nf
Li = 0
(RETURN )
(+)
3
1
TRANSMITTER VERSION
TERMINAL NUMBER
EASIDEW I.S.
PURA I.S.
EASIDEW
PRO I.S.
2
4
THE CAPACITANCE AND EITHER THE INDUCTANCE OR THE INDUCTANCE TO RESISTANCE RATIO
(L/R) OF THE CABLE MUST NOT EXCEED THE FOLLOWING VALUES:
ABCD
4.2mH
12.6 mH
33mH
μ
μ
THE ISOLATION OF THE SIGNAL W IRES WITH THE EASIDEW DISCONNECTED, MUST BE ABLE T O
WITHSTAND A 500V AC INSULATION TEST.
46 nF
613 nF
2.11 F
μ
Ω
Ω
Ω
μ
μ
μ
54 H/
217 H/
435 H/
THE INSTALLATION MUST COMPLY W ITH T HE INSTALLATION PRACTICES OF THE COUNTRY OF
USE. i.e. ANSI/ISA RP12.6 (INSTALLATION OF INTRINSICALLY SAFE SYSTEMS FOR HAZARDOUS
[CLASSIFIED] LOCATIONS) AND THE NATIONAL ELECTRICAL CODE ANSI/NFPA 70.
THE CAPACITANCE AND THE INDUCTANCE OF THE HAZARDOUS AREA CABLES MUST NOT
EXCEED THE VALUES GIVEN IN TABLE 1
Intrinsically safe(entity), Class 1, Div1, Group A,B,C,D
Hazardous Location Installations
1) Control room equipment may not use or generate over 250Vrms.
2) Wire all circuits for power supply per CEC Part 1.
3) Use only entity approved safety barrier or other associated
equipment that sa tisfy the following conditions:
V
CG <
V
max
, I
SC <
I
MAX
, C
a>
C
i
+ C
CABLE
, L
a >
L
i
+ L
CABLE
Transmitter entity parameters are as follows:
V max < 2.8Vdc
I max < 93mA
Ci = 37nF
Li = 0uH
4) WARNING: SUBSTITUTION OF COMPONENTS MAY IMPARE
INTRINSIC SAFETY.
5) Ex ia is defined as Intrinsically Safe.
Type
Isolated Repeater
Dual Isolated
Repeater
Transmitter Supply
Isolator
Transmitter Supply
Isolator
Smart Transmitter
Power Supply
Certificate Number
BAS98ATEX7343
UL Canada E106378CUL
BAS98ATEX7343
UL Canada
E106378CUL
BAS00ATEX7164
UL Canada E106378CUL
BAS00ATEX7164
UL Canada E106378CUL
BAS99ATEX7060
UL Canada E106378CUL
Interface
KFD0-CS-Ex1.50P
KFD0-CS-Ex2.50P
KFD2-CR-Ex1.20200
KFD2-CR-Ex1.30200
KFD2-STC4-Ex1.H
Connection to Easidew I.S.
Pin 1 (+)
Pin 2 (-)
Channel 1 - Pin 1 (+)
Channel 1 - Pin 2 (-)
Channel 2 - Pin 4 (+)
Channel 2 - Pin 5 (-)
Pin 1 (+ )
Pin 3 (-)
Pin 1 (+ )
Pin 3 (-)
Pin 1 (+ )
Pin 3 (-)
B.2 QPS Approved System Drawing
APPENDIX B
Michell Instruments 21
APPENDIX C
Easidew I.S. User Manual
Appendix C
Hazardous Area Certication
22 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
Appendix C Hazardous Area Certication
The Easidew I.S is certied compliant to the ATEX Directive (2014/34/EU), the IECEx
scheme and SI 2016 No. 1107 UKCA product marking scheme for use within Zone 0, 1
and 2 Hazardous Areas and has been assessed as being so by SGS FIMKO Oy, Finland
(Notied Body 0598) and SGS Baseefa UK (Approved Body 1180).
The Easidew I.S is certied compliant to the applicable North American Standards (USA
and Canada) for use within Class I, Division 1 and Class I, Zone 0 Hazardous Locations
and has been assessed as being so by QPS.
C.1 Product Standards
This product conforms to the Standards:
BS/EN60079-0:2012/A11:2013 CSA C22.2 No. 60079-0:19
BS/EN60079-11:2012 CSA C22.2 No. 60079-11:14
FM Class 3600:2018 CSA 61010-1-12(R2017)
FM Class 3610:2010 UL61010-1
IEC60079-0:2011 UL60079-0
IEC60079-11:2011 UL60079-11
APPENDIX C
C.2 Product Certication
This product is attributed with the product certication codes:
ATEX, UKCA & IECEx
II 1 G Ex ia IIC T4 Ga (-20°C...+70°C)
North American
IS, Class I, Division 1, Groups A, B, C & D, T4
Class I, Zone 0, AEx ia IIC T4 Ga, Ex ia IIC T4 Ga
Tamb +70°C
C.3 Global Certicates/Approvals
ATEX SGS Baseefa 06ATEX0330X
IECEx IECExBAS 06.0090X
UKCA BAS21UKEX0014X
QPS LR1507-10
These certicates can be viewed or downloaded from our websites, at:
www.processsensing.com & www.michell.com
Michell Instruments 23
APPENDIX C
C.4 Terminal Parameters
Easidew I.S. User Manual
Ui
li
Pi
Ci
Li
C.5 Special Conditions of Use
1. The wiring connections to the free socket must be made via crimped
connectors in such a way that all the strands of the wire used are held
securely by the crimp.
2. The plastic plug and socket create a potential for electrostatic discharge
so must not be rubbed with a dry cloth or cleaned with solvents.
3. The Easidew I.S. Dew-Point Transmitter does not withstand the 500 V AC
insulation test to frame. This must be taken into account when installing
the equipment.
C.6 Maintenance and Installation
= 28 V
= 93 mA
= 820 mW
= 37 nF
= 0
The Easidew I.S. must only be installed by suitably qualied personnel and in accordance
with the instructions provided and the terms of the applicable product certicates.
Maintenance and servicing of the product must only be carried out by suitably trained
personnel or returned to an approved Michell Instruments Service Center.
24 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
APPENDIX D
Appendix D
Quality, Recycling
& Warranty
Information
Michell Instruments 25
APPENDIX D
Easidew I.S. User Manual
Appendix D Quality, Recycling & Warranty Information
Michell Instruments is dedicated to complying to all relevant legislation and directives.
Full information can be found on our website at:
www.michell.com/compliance
This page contains information on the following directives:
• Anti-Facilitation of Tax Evasion Policy
• ATEX Directive
• Calibration Facilities
• Conict Minerals
• FCC Statement
• Manufacturing Quality
• Modern Slavery Statement
• Pressure Equipment Directive
• REACH
• RoHS3
• WEEE2
• Recycling Policy
• Warranty and Returns
This information is also available in PDF format.
26 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
APPENDIX E
Appendix E
Return Document &
Decontamination Declaration
Michell Instruments 27
APPENDIX E
Easidew I.S. User Manual
Appendix E Return Document & Decontamination Declaration
Decontamination Certicate
IMPORTANT NOTE: Please complete this form prior to this instrument, or any components, leaving your
site and being returned to us, or, where applicable, prior to any work being carried out by a Michell
engineer at your site.
Instrument Serial Number
Warranty Repair? YES NO Original PO #
Company Name Contact Name
Address
Telephone # E-mail address
Reason for Return /Description of Fault:
Has this equipment been exposed (internally or externally) to any of the following?
Please circle (YES/NO) as applicable and provide details below
Biohazards YES NO
Biological agents YES NO
Hazardous chemicals YES NO
Radioactive substances YES NO
Other hazards YES NO
Please provide details of any hazardous materials used with this equipment as indicated above (use continuation sheet
if necessary)
Your method of cleaning/decontamination
Has the equipment been cleaned and decontaminated? YES NOT NECESSARY
Michell Instruments will not accept instruments that have been exposed to toxins, radio-activity or bio-hazardous
materials. For most applications involving solvents, acidic, basic, ammable or toxic gases a simple purge with dry
gas (dew point <-30°C) over 24 hours should be sufcient to decontaminate the unit prior to return.
Work will not be carried out on any unit that does not have a completed decontamination declaration.
Decontamination Declaration
I declare that the information above is true and complete to the best of my knowledge, and it is safe for Michell
personnel to service or repair the returned instrument.
Name (Print) Position
Signature Date
F0121, Issue 2, December 2011
28 97099 Issue 16.6, November 2022
Easidew I.S. User Manual
NOTES
Michell Instruments 29
www.ProcessSensing.com
http://www.michell.com
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