Michell Instruments Promet EExd User manual

Promet EExd
Process Moisture Analyzer
User’s Manual
97090 Issue 16.1
November 2019

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© 2019 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
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Promet EExd

Promet EExd User’s Manual
iv 97090 Issue 16.1, November 2019
Contents
Safety ...............................................................................................................................vii
Electrical Safety ..........................................................................................................vii
Pressure Safety ...........................................................................................................vii
Toxic Materials ............................................................................................................vii
Repair and Maintenance ..............................................................................................vii
Calibration (factory validation) .....................................................................................vii
Safety Conformity .......................................................................................................vii
Abbreviations .................................................................................................................... viii
Warnings .......................................................................................................................... viii
1 INTRODUCTION ................................................................................................1
1.1 General .............................................................................................................. 1
1.2 Sample Gas Path ................................................................................................ 1
1.3 Operating Overview ............................................................................................ 2
1.4 User Display and Interface .................................................................................. 2
1.5 Advanced Sensor Technology .............................................................................. 2
1.6 Measurement Units ............................................................................................. 3
1.7 Elimination of Temperature Effects ....................................................................... 3
1.8 Calibration Maintenance ...................................................................................... 4
1.9 Promet EExd Sampling System ............................................................................ 4
2 INSTALLATION ..................................................................................................5
2.1 Electrical Safety .................................................................................................. 5
2.1.1 Equipment Ratings and Installation Details ...................................................... 5
2.2 Hazardous Area Safety ........................................................................................ 8
2.3 Pressure Safety .................................................................................................. 9
2.4 Lifting and Handling ........................................................................................... 9
2.5 Analyzer System ............................................................................................... 10
2.5.1 Pipework .................................................................................................... 11
2.5.2 Power Connection ...................................................................................... 13
2.5.3 Analog and Digital Communications ............................................................. 14
2.5.4 Process Alarms and Analyzer Status Alarms .................................................. 14
2.6 Promet EExd Start-Up Purge Procedure .............................................................. 15
2.7 Sample Gas Flows ............................................................................................ 16
2.8 Sample Flow Alarms (Optional) .......................................................................... 16
3 OPERATION ....................................................................................................17
3.1 System Operation ............................................................................................. 17
3.2 User Interface .................................................................................................. 17
3.2.1 Interface Controls ....................................................................................... 17
3.2.2 ‘Up/Down Arrow’ Buttons ............................................................................. 18
3.2.3 ‘SELECT’ Button .......................................................................................... 18
3.2.4 ‘MENU/MAIN’ Button ................................................................................... 18
3.3 Menu Structure ................................................................................................ 19
3.4 MAIN MENU Page ............................................................................................. 20
3.5 STATUS Page ................................................................................................... 20
3.6 LOGGING MENU Page ....................................................................................... 21
3.6.1 VIEW LOGGED DATA Page ........................................................................... 21
3.6.2 VIEW STATISTICS Page ............................................................................... 22
3.6.3 VIEW SYSTEM FAULTS Page ........................................................................ 23
3.7 VIEW/ADJ VARIABLES Page .............................................................................. 23
3.7.1 Password .................................................................................................... 23
3.7.2 VARIABLES Pages ....................................................................................... 24
3.7.3 Single Channel Configuration VARIABLES Pages ............................................ 24

Promet EExd User’s Manual
Michell Instruments v
3.7.4 Dual Channel Configuration VARIABLES Pages .............................................. 25
3.8 SENSOR INFO Page .......................................................................................... 26
3.9 CONTACT INFO Page ....................................................................................... 27
4 MAINTENANCE ................................................................................................28
4.1 Enclosure Cover and User Interface ................................................................... 28
4.2 Replacement of the Moisture Sensor Assembly ................................................... 29
4.3 Replacement of the Flow Switch (if fitted) .......................................................... 31
4.4 Troubleshooting ................................................................................................ 32
4.4.1 Error Messages ........................................................................................... 32
4.4.2 Logged Error Codes ..................................................................................... 33
4.4.3 Analyzer Status Alarm Relay......................................................................... 34
Figures
Figure 1 Promet EExd Sampling System ....................................................................4
Figure 2 Power Connection Connector .......................................................................5
Figure 3 Earthing Stud And Nut Washer Assembly .....................................................6
Figure 4 Promet EExd Mounting Drawing .................................................................10
Figure 5 Pipework Connections ...............................................................................11
Figure 6 Hook-up Wiring Diagram ...........................................................................13
Figure 7 Minimum Requirements for Start-up Purging ..............................................16
Figure 8 MAIN Page in Single Channel (top) and Dual Channel Modes .......................17
Figure 9 User Interface ..........................................................................................17
Figure 10 Up/Down Arrow Buttons ...........................................................................18
Figure 11 ‘SELECT’ Button ........................................................................................18
Figure 12 ‘MENU/MAIN’ Button .................................................................................18
Figure 13 Menu Structure ........................................................................................19
Figure 14 MAIN MENU Page .....................................................................................20
Figure 15 STATUS Page ...........................................................................................20
Figure 16 LOGGED DATA Page .................................................................................21
Figure 17 STATISTICS Page .....................................................................................22
Figure 18 LOGGED ERROR Page ...............................................................................23
Figure 19 PASSWORD Page ......................................................................................23
Figure 20 VARIABLES Page ......................................................................................24
Figure 21 SENSOR INFO Page ..................................................................................26
Figure 22 CONTACT INFO Page ................................................................................27
Figure 23 Ribbon Cable Connection ..........................................................................29
Figure 24 Moisture Sensor Assembly Replacement .....................................................30
Figure 25 Error Message Line ...................................................................................32
Figure 26 Logged Error Codes ..................................................................................33
Figure 27 Mounting Drawing ....................................................................................38
Figure 28 Pipework Connections ...............................................................................39
Figure 29 System Wiring Diagram .............................................................................40
Figure 30 Calibration Correction Data........................................................................50
Figure 31 Reading Holding Registers State Diagram ...................................................62
Figure 32 Write Single Register State Diagram ...........................................................64

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vi 97090 Issue 16.1, November 2019
Appendices
Appendix A Technical Specifications .............................................................................. 36
A.1 Mounting Drawing .......................................................................38
A.2 Pipework Connections .................................................................. 39
A.3 System Wiring Diagram ................................................................40
Appendix B Variable Definitions ...................................................................................42
Appendix C Software ...................................................................................................47
C.1 System Requirements ..................................................................47
Appendix D Modbus RTU Communications .................................................................... 49
D.1 Introduction ................................................................................ 49
D.2 Modbus RTU Basics ...................................................................... 49
D.3 Physical Layer .............................................................................49
D.4 Termination Resistor ....................................................................50
D.5 Register Map ............................................................................... 50
Appendix E Modbus RTU Details ..................................................................................55
E.1 Message Framing .........................................................................55
E.2 Implemented Functions ................................................................ 56
E.3 Exceptions .................................................................................. 60
Appendix F Register Number Formats...........................................................................62
Appendix G Hazardous Area Certification ......................................................................68
G.1 Product Standards .......................................................................68
G.2 Product Certification ....................................................................68
G.3 Global Certificates/Approvals ........................................................68
G.4 Special Conditions of Use ............................................................. 69
G.5 Maintenance and Installation ........................................................69
Appendix H Pressure Equipment Directive Compliance Statement ................................... 71
Appendix I Quality, Recycling & Warranty Information ................................................... 73
Appendix J Return Document & Decontamination Declaration ........................................ 75

Promet EExd User’s Manual
Michell Instruments vii
Safety
This manual contains all the required information to install, operate and maintain the Promet EExd. Prior
to installation and use of this instrument, this entire manual should be read and understood. Installation
and operation of this product should be carried out by suitably competent personnel only. The operation
of this product must be in accordance with the terms of this manual and associated safety certicates.
Incorrect installation and use of this product for other than its intended purpose will render all warranties
void.
This product is intended for use in a Hazardous Area and is awarded an ATEX, IECEx and CSA Certicate.
The relevant certicates should be fully examined prior to installation or use of this product.
!
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 and where particular attention to
personal and personnel safety must be observed.
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. The input power supply voltage limits are 90 to 260 V AC,
47/63 Hz.
Pressure Safety
DO NOT permit pressures greater than the safe working pressure to be applied directly to the instrument.
Refer to the Technical Specications 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 only be maintained either by the manufacturer or an accredited service agent. Refer
to www.michell.com for details of Michell Instruments’ worldwide oces contact information.
Calibration (factory validation)
Prior to shipment, the analyzer undergoes stringent factory calibration to internationally traceable
standards, NPL (UK) and NIST (USA). Due to the inherent stability of the instrument, only periodic
calibration is required under normal operating conditions.
Michell Instruments recommends that calibration of the sensor should be maintained on a 12 monthly
basis to ensure optimum operation. Michell Instruments oers a calibration exchange program, where
a refurbished and re-certied sensor is supplied as an operational replacement and the original item
returned to Michell to complete the exchange.
NOTE: This interval may need to be reduced if the operation of the sensor is within potentially
aggressive or corrosive sample media (such as sour natural gas). The calibration interval
may therefore need to be shortened to 6 months (or lower in extreme cases) in order to
maintain satisfactory analyzer performance.
Safety Conformity
This product meets the essential protection requirements of the relevant EU directives. Further details of
applied standards may be found in the product specication.

Promet EExd User’s Manual
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Abbreviations
The following abbreviations are used in this manual:
A Ampere
AC alternating current
barg pressure in bar (gauge)
°C degrees Celsius
°F degrees Fahrenheit
DC direct current
dp dew point
EU European Union
lb pound
lb/MMscf pounds per million standard cubic feet
lbf-ft pound force per foot
kg kilogram
mA milliampere
max maximum
min minute(s)
mg/m3 milligrams per cubic meter
mm millimeters
mV millivolt(s)
N/C normally closed
N/O normally open
Nl/min normal liters per minute
ppmV parts per million by volume
psig pressure in pound(s) per square inch (gauge)
RH relative humidity
scfh standard cubic feet per hour
temp temperature
V Volts
Warnings
The following general warnings listed below are applicable to this instrument. They are
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.
Where this symbol appears in the following sections it is used
to indicate areas of potential risk of electric shock.

Promet EExd User’s Manual
Michell Instruments 1
INTRODUCTION
1 INTRODUCTION
1.1 General
The Promet EExd is designed for continuous, automatic measurement of the moisture
content of processed natural gas, utilizing the Michell Ceramic Moisture Sensor. It is the
result of more than 30 years’ experience in the supply of analyzers to the Worldwide Oil
& Gas Industry.
The analyzer comprises either a single or a dual channel moisture measurement sensor
cell, control electronics and a display interface housed in an Exd enclosure. The analyzer
is ATEX Directive, IECEx or cCSAus compliant for use in a Zone 1 or 2 Hazardous Area
and Class I, Div 1 Hazardous Location. See marking label located on right hand side of
analyzer to identify approvals. An accompanying sample handling panel, designed to be
positioned close to the process sample point to prepare the sample prior to entry into
the Promet EExd, can also be supplied.
The instrument offers several user-selectable display options based on a calibrated
dew-point measurement range of -100 to +20°C (-148 to +68°F), traceable to the
humidity metrology standards of NPL (UK) and NIST (USA). The instrument further
provides indication only in the ranges of +20 to +30°Cdp (+68 to +86°Fdp) and -100 to
-120°Cdp (-148 to -184°F), equating to a moisture measurement capability of <1ppbV
to >30,000 ppmV.
The requirements for operation are a 90 to 260 V AC, 47/63 Hz power supply of 180W
and field communications Modbus RTU and/or 4-20 mA. Refer to the System Wiring
Diagram in Appendix A.
1.2 Sample Gas Path
The Promet EExd analyzer system must be supplied with gas at the required pressure,
via a sample gas handling panel providing suitable pressure, filtration & flow control.
Sample gas entry and exit ports direct the gas through flame arrestors which, along with
the Exd enclosure, provide the explosion proof protection. 1 or 2 separate measurement
channels can be accommodated within the instrument.
The measurement system components are housed within a cast aluminum Exd rated
enclosure. The enclosure has a screw cover incorporating a sealed window. It is
chromate primed, polyester coated in black, and provides environmental protection to
IP66/NEMA 4. An enclosure breather is fitted in the form of an additional flame arrestor.
It is important that no pipe connection is made to this breather and that no restriction
is allowed to occur.
All sample gas-wetted metallic parts are manufactured in AISI 316L stainless steel with
Viton soft parts that comply with the NACE standard MR-01-75 (latest edition). Tube
fittings are twin ferrule compression type. All electrical and gas connections are made
through the base of the enclosure. Refer to the Mounting Drawing in Appendix A.
Channel 1 flow components comprise the following:
• (Optional) Flow Switch 1 (FS1): Provides indication that a flow
is present throughout the moisture measurement stream
• Pressure Transducer 1 (PT1): Provides the measurement of
the sample gas pressure within the moisture measurement cell

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INTRODUCTION
Channel 2 flow components comprise the following:
• (Optional) Flow Switch 2 (FS2): Provides indication that a flow
is present throughout the moisture measurement stream
• Pressure Transducer 2 (PT2): Provides the measurement of
the sample gas pressure within the moisture measurement cell
1.3 Operating Overview
The system continuously measures dew point/moisture and pressure in an uninterrupted
gas stream flow. The flow switch, if fitted, will notify the system if the gas flow falls
below the recommended rate.
Moisture and pressure for each channel are logged at a user-defined interval. The logs
are available through the user interface or via the serial communications. Two 4–20 mA
outputs for each channel are available to remotely read the dew point/moisture and
pressure in real time.
1.4 User Display and Interface
The Promet EExd User Display and Interface Unit is presented via the circular window
of the enclosure. Operation is achieved by a unique system, which allows full control
through the glass of the enclosure cover. The cover is fully detachable for greater
access into the enclosure during the installation and initial set-up of the instrument.
During normal operation of the instrument the cover must remain fully secured.
1.5 Advanced Sensor Technology
The Promet EExd utilizes the Michell Ceramic Moisture Sensor, an advanced impedance
sensor technology with more than 1,000 installations in natural gas and petrochemical
applications today. Semiconductor thick- and thin-film technologies combine in metallized
ceramics and achieve a durable sensor with measurement capability from lower than 10
ppbV moisture content and high-pressure capability up to 138 barg (2000 psig).
Unlike older aluminum-oxide technologies, the inherent immunity to pressure shock of
the Ceramic Sensor avoids the risk of sensor failure at commissioning or shut-down.
The inert nature of the sensor gives long-term resistance to chemical attack, even in
extremely sour gas with percentage level H2S concentrations. The Ceramic Sensor
response characteristic is proportional to the partial pressure of water vapor in the gas
being measured, which is directly related to the dew-point temperature.

Promet EExd User’s Manual
Michell Instruments 3
INTRODUCTION
1.6 Measurement Units
The Promet EExd offers complete flexibility for the user to select their preference of
hygrometric units. Integral pressure measurement enables unit conversions from dew
point to moisture content, or dew point to dew point for different pressure conditions.
The available units of dew point/moisture content are as follows:
Dew-Point Temperature
• °C or °F dew point
• °C or °F dew point calculated for a set pressure level input by
the user, for either ideal or natural gas
Moisture Content (parts per million)
• ppmV for ideal gas (Ppm(v) IG)
• ppmV for natural gas (Ppm(v) NG)
Moisture Content (pounds per million standard cubic feet)
• lb/MMscf for natural gas (LBMMSCF)
Milligrams per normal cubic meter
• mg/m3 natural gas (mgm-3)
The firmware of the Promet EExd incorporates conversion data for ideal gases and
natural gas. For natural gas the conversions are performed based on the long established
IGT Research Bulletin No. 8 or the recently published ISO 18453, to customer order
preference.
1.7 Elimination of Temperature Effects
To ensure continuous optimum analysis conditions the Promet EExd Main Unit is
temperature controlled (internally) at a stable level. The control temperature level is
selected to suit the climate at the point of installation, being set to the normal maximum
temperature. Such steady state control within the analyzer greatly reduces the effects
of diurnal (day-night) swings in temperature. These temperature changes could induce
transitional adsorption and desorption effects of the flowing sample, resulting in
erroneous measurements.
In addition, the Promet EExd utilizes an advanced temperature compensation algorithm
that automatically maintains best possible measurement accuracy in the event of heater
failure or if the prevailing climate exceeds the set temperature level.

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INTRODUCTION
1.8 Calibration Maintenance
Maintenance of calibration is essential to the lifetime performance of all analyzers. To
ensure that all customers worldwide can maintain the performance of their Promet EExd,
the unique Michell Calibration Exchange Service offers freshly calibrated replacement
Ceramic Sensors certified traceable to NPL and NIST. As the calibration characterization
data for each Promet EExd Sensor is programmed into on-board non-volatile memory,
fitment of the Calibration Exchange Sensor refreshes the calibration, returning the
measurement performance to day-one with down-time of only a few minutes while
the interchange is made. No programming or data input is required by the user to
complete this. The calibration exchange is available globally on swift delivery, typically
less than two weeks, and at the same or less then the cost of a traditional ‘return to
manufacturer’ re-calibration service.
The recommended calibration maintenance interval is 12 months for sweet gases and
6 months for sour gases.
Michell recognises that some customers wish to carry out their own calibration
adjustments in the field using either a portable dew-point generator (ATSM D5454),
or against a calibrated reference hygrometer or certified moisture-in-gas cylinders.
The Promet EExd accommodates all such needs within the operating firmware that
offers user-friendly access to the calibration characterization table for re-calibration
adjustments to be made at just one point (for example, using a certified cylinder gas)
or multiple points (using a field generator) across the measurement range.
1.9 Promet EExd Sampling System
(Optional – see separate manual if you have purchased this item)
Figure 1 Promet EExd Sampling System
Good sample conditioning and handling is particularly important in the field of moisture
measurement. As the moisture sensor has to be exposed directly to the process liquid
stream in order to detect the dissolved moisture present, key sampling issues such
as the avoidance of particulate contamination are imperative to successful operation.
Michell’s 30 years of expertise in on-line process moisture analyzers are used to optimize
the design of the Promet EExd Sampling Systems.
Contact Michell Instruments for further details: www.michell.com.

Promet EExd User’s Manual
Michell Instruments 5
INSTALLATION
2 INSTALLATION
2.1 Electrical Safety
!
WARNING:
During the installation of this product ensure that all
applicable national and local electrical safety regulations
are observed.
WARNING:
Isolate the power prior to installation.
WARNING:
Always ensure that power is switched off prior to accessing
the product for any purpose other than normal operation or
prior to disconnecting any cables.
2.1.1 Equipment Ratings and Installation Details
The following mandatory statements refer to the Ex certified Promet EExd Analyzer only
(not including the sampling system).
This equipment must be supplied with a voltage between the range of 90 to 260 V AC,
47/63 Hz. Maximum power rating is 180 W.
The power is connected via PL1 on the mains connector PCB.
Figure 2 Power Connection Connector
All input and output connectors are 2-part PCB mounted type, rated at 300 V 10 A.
The detachable, screw terminal half of each connector is designed to accept 0.5 to
2.5mm2 [24 -12 AWG] stranded or solid conductors.

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INSTALLATION
Any power connection cable should be 3 core over sleeved, with minimum 0.5mm
insulation and rated at 300 V. Cables should have Live (L), Neutral (N) and Earth
[Ground] (E) conductors. Ensure suitably rated power supply cables and glands are
used to ensure that electrical safety is maintained. Connect each of the Live (L), Neutral
(N) and Earth [Ground] (E) conductors to the similarly marked terminals (L, N, E) on
the Power In connector shown in Figure 3 above. Ensure the power supply can deliver
sufficient power consumption requirement.
Any power supply terminals and voltages must be suitably separated from the other I/O
requirements of this product.
Before applying power, perform a continuity test to ensure that the power supply cable
and product are effectively connected to the protective Earth.
The Protective Earth terminal is mounted internally and the Earth wire connected to it
should never be disconnected. The product enclosure is supplied with an external earth
stud at the lower right hand side. At installation, connect this earth stud to plant earth
by a minimum 4mm2 earthing bonding. M6 stud and 2 off M6 nuts and washers, all
nickel plated.
Figure 3 Earthing Stud And Nut Washer Assembly
Fuse: A replacement fuse can be obtained by contacting Michell Instruments' technical
support. Fuse rating = 5 x 20mm 2.5 A anti-surge to IEC 60127-2.
This product is designed to be safe at least under the following conditions: between a
temperature range of -40 to +60°C (-40 to +148°F), in maximum 80% relative humidity
for temperatures up to +31°C (+88°F) decreasing linearly to 50% RH at +50°C
(+122°F). Supply voltages of ±10% and transient over voltages up to Overvoltage
Category II. Pollution Degree 2. Altitudes up to 2000m. Outdoor mounting is permitted
using suitably rated glands equivalent to NEMA 4 / IP66. See Appendix A, Technical
Specification, for full operating parameters.
Do not remove or exchange any of the cables or electrical components supplied with
this product. Doing so will invalidate all warranties.
There are no additional or special electrical safety requirements other than those
referred to in this manual.

Promet EExd User’s Manual
Michell Instruments 7
INSTALLATION
Location and mounting arrangements - refer to the relevant sections of this manual for
the location and mounting details.
Installation of this equipment must include the provision of a suitable and locally
positioned power isolation switch or circuit breaker. Indication of the purpose of the
switch or circuit breaker is strongly recommended. An over-current protection device
should be rated to a maximum of 10 A.
This equipment and all power isolation devices must be installed in a location and
position that allows safe and easy access to their operation and is able to rigidly support
the equipment.
Do not install this equipment in a location that would expose it to impact or high levels
of vibration.
Operation of this equipment, other than in a manner specified by the manufacturer, may
impair the safety protections provided.
The safe installation of this equipment and any system incorporating this equipment is
the responsibility of the installer. Ensure local regulations and requirements are referred
to prior to any installation commencing.

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INSTALLATION
2.2 Hazardous Area Safety
Refer to Appendix G for the Hazardous Area Certification of this product.
This product is fitted with a marking label that contains Hazardous Area information
pertinent to the suitable location and installation.
During all installation and operation activities, local regulations and permitted working
routines must be observed. Installation should only be performed by competent personnel
and in accordance with the latest version of IEC/EN60079-14 or local equivalent.
Repair and servicing of this equipment must only be carried out by the manufacturer.
An Installation and Maintenance Information Sheet is supplied separately to the manual.
WARNING:
This product is certified safe for use in a Zone 1 and Zone 2
area only. This product must not be installed or used within
a Zone 0 area.
!
WARNING:
This product must not be operated within an explosive
atmosphere greater than 1.1 bara.
WARNING:
This product must not be operated with enriched oxygen
gas samples (more than 21% oxygen content).
WARNING:
This product must not be operated outside of the
temperature range of -40 to +60°C
WARNING:
The enclosure of this product provides Exd protection, partly
through the threads used for mounting the lid, stopping
plugs and cable gland. At all times effort should be made to
ensure these threads are suitably protected from damage
and that only appropriately rated mating parts are applied
to them, in accordance with the certifying requirements.

Promet EExd User’s Manual
Michell Instruments 9
INSTALLATION
2.3 Pressure Safety
!
WARNING:
This product is used in conjunction with pressurized gases.
Observe pressurized gas handling precautions.
!
WARNING:
Pressurized gas is dangerous.
Pressurized gas should only handled by suitably trained personnel.
This product requires pressurized gas to be connected to it. Observe pressurized gas
handling regulations. Only suitably trained personnel should carry out tasks that include
the use of pressurized gas mediums.
2.4 Lifting and Handling
!
WARNING:
This instrument is in excess of 18kg.
Personnel must observe suitable lifting and handling precautions.
This product is not designed as portable or transportable equipment. It should be rigidly
fixed in position as per the full installation instructions.
The weight of the analyzer is in excess of 18kg. Therefore, appropriate lifting and
handling techniques should be used during the installation process. Before commencing
any lifting or handling ensure that its intended location is suitable and appropriately
prepared. Make sure that mounting point design considerations have employed locally
approved safety factors.
When handling and installing this product (particularly after removal from its packaging)
ensure that it is not dropped, impacted or subjected to high levels of vibration or
environmental conditions that may impair its operation.

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INSTALLATION
2.5 Analyzer System
Refer to the Installation & Maintenance Information sheet (supplied separately) and the
System Drawings in Appendix A.
The instrument is housed in an aluminum EExd enclosure suitable for wall or panel
mounting. Four mounting points are available with M12 clearance holes on fixing
centres of X = 270mm x Y = 318mm.
Height: 355mm (13.9”)
500mm (19.68”) including installation clearance
Width: 310mm (12.20”)
500mm (19.68”) including installation clearance
Depth: 245mm (9.64”)
The enclosure provides environmental ingress protection IP66 and should be mounted
vertically in a location free of any appreciable vibration. It should be placed in a shaded
position to prevent heating effects through sun radiation.
The weight of the analyzer is 21kg (46lbs).
Figure 4 Promet EExd Mounting Drawing
270mm 10.63"
318mm 12.52"
355mm [13.9"]
245mm 9.65"
290mm [11.41"]
4 o M12 (1/2")
Clearance
Enclosure Breather
Flame Arrestor
Do NOT obscure
Sample Out - Channel 2 (Optional)
Flame Arrestor
1/8" NPT Female (ATEX/IECEx/CSA)
Sample In - Channel 2 (Optional)
Flame Arrestor
1/8" NPT Female (ATEX/IECEx/CSA)
Sample in - Channel 1
Flame Arrestor
1/8" NPT Female (ATEX/IECEx/CSA)
Sample out - Channel 1
Flame Arrestor
1/8" NPT Female (ATEX/IECEx/CSA)
310mm [12.20"]
Cable Entry Glands
3 o M20 (ATEX)
3 o 1/2" NPT (CSA)

Promet EExd User’s Manual
Michell Instruments 11
INSTALLATION
2.5.1 Pipework
CHANNEL 1 CHANNEL 2


MICHELL MOISTURE
SENSOR
PRESSURE
TRANSMITTER
GAS IN GAS OUT
FLAME
ARRESTORS
FLOW
SWITCH
(optional)
GAS SAMPLING BLOCK




MICHELL MOISTURE
SENSOR
PRESSURE
TRANSMITTER
GAS IN GAS OUT
FLAME
ARRESTORS
FLOW
SWITCH
(optional)
GAS SAMPLING BLOCK


FLAME
ARRESTOR
BREATHER

Figure 5 Pipework Connections
Note: Ensure that the process sample gas supply line is well flushed through
to clear any liquids and debris present prior to connection to the instrument. A
sample handling system must prepare the gas in terms of pressure regulation
and filtration before entering into the measurement system.
In accordance with the Certification requirements, the Promet EExd must have, as a
minimum, the components described in Figure 7.
The pipework connections are as follows:
Water dew-point Channel 1 Gas Sample inlet
(Maximum pressure of 138 barg (2000 psig))
1/8” NPT(F)
Water dew-point Channel 1 Gas Sample outlet
(Vent to atmosphere or low pressure are line)
Water dew-point Channel 2 Gas Sample inlet
(Maximum pressure of 138 barg (2000 psig))
Water dew-point Channel 2 Gas Sample outlet
(Vent to atmosphere or low pressure are line)

Promet EExd User’s Manual
12 97090 Issue 16.1, November 2019
INSTALLATION
The following points should be considered when installing the sample gas supply line:
PTFE tape is recommended for pipe connections. Solvent based pipe thread sealant
should not be used, as condensable components or contaminates can be leached during
the curing period.
It is recommended that Viton is used for all O-rings.
Care and attention to the position and installation of the piping will minimize problems
caused by avoidable contamination of the measurement system. The most common
cause of difficulty is the accumulation of liquid in impulse lines during a shutdown
period. If the measurement system has not been isolated on restart-up, condensate
can be displaced into components and associated pipe work within the measurement
system.
If this event follows a period when process lines may have been contaminated by non-
hydrocarbons, e.g. glycol, corrosion inhibitors, etc., the problem is magnified. Similarly,
difficulty will be encountered in sample gases carrying liquids, including hydrocarbon
liquids.
Our recommendations are:
• The sampling point on the process line should be on the top of the pipe. If
a radial probe is used, the orifice should face downstream. Sample should
be taken from middle 1/3 pipe internal diameter.
• The internal volume of the impulse tubing between the process line and
any sampling system should be as low as possible (sample lines should
be kept as short as possible) to minimize response lag time to changing
process conditions.
• Piping should be lagged and/or trace heated if ambient temperatures
could cause the sample gas to fall below its dew-point temperature.
• A drain valve should be placed at the low point (if any) in the system.
• It should be standard procedure to isolate the measurement system
during shutdowns or when plant problems are being experienced. The
supply lines must be fully purged before restarting.
• The relatively large area of surfaces and internal volume of pressure
regulators can be particularly troublesome if contamination is experienced.
Prolonged purging with gas may be necessary to remove the contamination.
Stripping and cleaning, followed by purging of the system, is preferred.
• Avoid sample gas streams that are already very close to the dew point
or which have dispersed liquid (not necessarily hydrocarbon) burden. In
such cases, sampling from fast loops and/or from downstream of existing
catch pot/coalesce systems is always preferred.
NOTE: Failure to observe these recommendations will potentially cause
problems of contamination as well as causing consequential inaccurate,
unreliable and inconsistent monitoring. If a top-entry sample point
is not available, extra attention should be given to the design of the
sample line installation to avoid unwanted contamination.