Michell Instruments LQD-MON/SYS Manual

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Liquidew EExd
Process Moisture Analyzer
User’s Manual
97097 Issue 13.1
July 2018
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Please fi ll out the form(s) below for each instrument that has been purchased.
Use this information when contacting Michell Instruments for service purposes.
Analyzer
Serial Number
Invoice Date
Location of Instrument
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Analyzer
Serial Number
Invoice Date
Location of Instrument
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Analyzer
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Liquidew EExd
For Michell Instruments' contact information please go to
www.michell.com
© 2018 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.
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Liquidew EExd User’s Manual
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 Liquid Sample Path ............................................................................................. 1
1.3 Operating Overview ............................................................................................ 2
1.4 User Display and Interface .................................................................................. 2
1.5 Advanced Sensor Technology .............................................................................. 2
1.6 Measurement Units ............................................................................................. 2
1.7 Elimination of Temperature Effects ....................................................................... 3
1.8 Calibration ........................................................................................................ 3
1.9 Liquidew 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 Connections ...................................................................................... 12
2.5.3 Analog and Digital Communications ............................................................. 13
2.5.4 Process Alarms and Analyzer Status Alarms .................................................. 13
2.6 Liquidew EExd Start-up Purge Procedure ............................................................ 14
2.7 Sample Flows ................................................................................................... 15
3 OPERATION ....................................................................................................16
3.1 System Operation ............................................................................................. 16
3.2 User Interface .................................................................................................. 16
3.2.1 Interface Controls ....................................................................................... 16
3.2.2 ‘Up/Down Arrow’ Buttons ............................................................................. 17
3.2.3 ‘SELECT’ Button .......................................................................................... 17
3.2.4 ‘MENU/MAIN’ Button ................................................................................... 17
3.3 Menu Structure ................................................................................................ 18
3.4 MAIN MENU Page ............................................................................................. 19
3.5 STATUS Page ................................................................................................... 19
3.6 LOGGING MENU Page ....................................................................................... 20
3.6.1 VIEW LOGGED DATA Page ........................................................................... 20
3.6.2 VIEW STATISTICS ....................................................................................... 21
3.6.3 VIEW SYSTEM FAULTS Page ........................................................................ 21
3.7 VIEW/ADJ VARIABLES Page .............................................................................. 22
3.7.1 Password .................................................................................................... 22
3.7.2 VARIABLES Pages ....................................................................................... 22
3.7.3 Single Channel Confi guration Variables Pages ................................................ 23
3.7.4 Dual Channel Confi guration Variables Pages .................................................. 24
3.7.5 User-Defi ned Solutes ................................................................................... 25
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Liquidew EExd User’s Manual
3.7.5.1 Editing the Table of Cs Values ................................................................ 25
3.7.5.2 Editing the Label for the User-defi ned Solute........................................... 25
3.8 SENSOR INFO Page ......................................................................................... 26
3.9 CONTACT INFO Page ....................................................................................... 26
4 MAINTENANCE ................................................................................................27
4.1 Enclosure Cover and User Interface ................................................................... 27
4.2 Replacement of the Sensor Assembly ................................................................. 28
4.3 Replacement of the Flow Meter ......................................................................... 30
4.4 Troubleshooting ................................................................................................ 31
4.4.1 Error Messages ........................................................................................... 31
4.4.2 Error Messages Flashing over Displayed Values ............................................. 31
4.4.3 Logged Error Codes ..................................................................................... 32
4.4.4 Analyzer Fault Alarm Relay ........................................................................... 33
Figures
Figure 1 Liquidew EExd Sampling System ..................................................................4
Figure 2 Power Connection Connector .......................................................................5
Figure 3 Earthing Stud And Nut Washer Assembly .....................................................6
Figure 4 Liquidew EExd Dimensions ........................................................................10
Figure 5 Pipework Connections ...............................................................................11
Figure 6 Hook-up Wiring Diagram ...........................................................................13
Figure 7 Minimum Requirements for Start-up Purging .............................................. 15
Figure 8 MAIN Page in Single Channel (top) and Dual Channel Modes .......................16
Figure 9 User Interface ..........................................................................................16
Figure 10 Up/Down Arrow Buttons ...........................................................................17
Figure 11 ‘SELECT’ Button ........................................................................................17
Figure 12 ‘MENU/MAIN’ Button .................................................................................17
Figure 13 Menu Structure ........................................................................................18
Figure 14 MAIN MENU Page .....................................................................................19
Figure 15 STATUS Page ...........................................................................................19
Figure 16 LOGGED DATA Page .................................................................................20
Figure 17 STATISTICS Page .....................................................................................21
Figure 18 SYSTEM FAULTS Page ............................................................................... 21
Figure 19 PASSWORD Page ......................................................................................22
Figure 20 VARIABLES Pages (Examples) ...................................................................23
Figure 21 SENSOR INFO Page ..................................................................................26
Figure 22 CONTACT INFO Page ................................................................................26
Figure 23 Ribbon Cable Connection ..........................................................................28
Figure 24 Moisture Sensor Assembly Replacement ..................................................... 29
Figure 25 Flow Meter Replacement ...........................................................................30
Figure 26 Error Message Line ...................................................................................31
Figure 27 Logged Error Codes ..................................................................................32
Figure 28 Mounting Drawing ....................................................................................37
Figure 29 Pipework Connections ...............................................................................38
Figure 30 System Wiring Diagram .............................................................................39
Figure 31 Calibration Correction Data........................................................................49
Figure 32 Reading Holding Registers State Diagram ...................................................64
Figure 33 Write Single Register State Diagram ...........................................................66
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Liquidew EExd User’s Manual
Appendices
Appendix A Technical Specifi cation ............................................................................... 35
A.1 Mounting Drawing ....................................................................... 37
A.2 Pipework Connections .................................................................. 38
A.3 System Wiring Diagram ................................................................ 39
Appendix B Variable Defi nitions .................................................................................... 41
Appendix C Software ................................................................................................... 46
C.1 System Requirements ..................................................................46
Appendix D Calibration Correction ................................................................................48
D.1 Overview ....................................................................................48
D.2 Calibration Software .....................................................................49
D.3 Calibration Procedure ................................................................... 50
Appendix E Modbus RTU Communications .................................................................... 53
E.1 Introduction ................................................................................ 53
E.2 Modbus RTU Basics ......................................................................53
E.3 Physical Layer ............................................................................. 53
E.4 Termination Resistor .................................................................... 54
E.5 Register Map ...............................................................................54
Appendix F Modbus RTU Details ..................................................................................63
F.1 Message Framing ......................................................................... 63
F.2 Implemented Functions ................................................................ 64
F.3 Exceptions .................................................................................. 68
Appendix G Register Number Formats........................................................................... 70
Appendix H Hazardous Area Certifi cation ...................................................................... 75
H.1 Product Standards ...................................................................... 75
H.2 Product Certifi cation ................................................................... 75
H.3 Global Certifi cates/Approvals ....................................................... 75
H.4 Special Conditions of Use ............................................................. 76
H.5 Maintenance and Installation ........................................................ 76
Appendix I Quality, Recycling & Warranty Information ................................................... 78
Appendix J Return Document & Decontamination Declaration ........................................ 80
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Liquidew EExd User’s Manual
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Safety
This manual contains all the required information to install, operate and maintain the Liquidew 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 certifi 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 Certifi cate. The relevant certifi 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 Specifi 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 offi 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 offers a calibration exchange program, where a refurbished and re-certifi 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.
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Abbreviations
!
DANGER
Electric
Shock Risk
The following abbreviations are used in this manual:
AC alternating current atm pressure unit (atmosphere) barg pressure unit (=100 kP or 0.987 atm) gauge °C degrees Celsius °F degrees Fahrenheit dp dew point EU European Union GPM gallons per minute Hz Hertz IEC International Electrotechnical Commission kg kilogram l/min liters per minute ml/min milliliters per minute l/min normal liters per minute lb pound mA milliampere max maximum min minute(s) mV millivolt(s) N/C normally closed N/O normally open No number ppm
parts per million (by weight)
W
psig pound(s) per square inch (gauge) RH relative humidity RTU Remote Terminal Unit temp temperature V Volts " Inch
Liquidew EExd User’s Manual
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.
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Liquidew EExd User’s Manual
1 INTRODUCTION
1.1 General
The Liquidew EExd is designed for continuous, automatic measurement of the moisture content in hydrocarbon solutes, 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 and petrochemical 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 Liquidew 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 provides indication in moisture in liquids (ppm
INTRODUCTION
).
W
The requirements for operation are a 90 to 260 V AC, 47/63 Hz power supply of 180W and fi eld communications Modbus RTU and/or 4-20 mA. Refer to the System Wiring Diagram in Appendix B.3.
1.2 Liquid Sample Path
The Liquidew EExd analyzer system must be supplied with a liquid sample at a pressure up to 50 barg (725 psig), via a sample handling panel providing fi ltration & fl ow control. Suffi cient differential pressure will be required (typically greater than 0.5 barg (7.2 psig)) between the process sample source and return points. This should enable a ow between 0.1 and 0.3 l/min (0.03 and 0.08 GPM) through the Liquidew EExd and its associated sampling system. Sample entry and exit ports direct the liquid through fl ame arrestors which, along with the Exd enclosure, provide the explosion proof protection.
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 fi tted in the form of an additional fl ame arrestor. It is important that no pipe connection is made to this breather and that no restriction is allowed to occur.
For accuracy and long term reliability, the temperature of the sample entering the Liquidew EExd should be less than +40°C (+104°F) and higher than +10°C (+50°F). The sample and operating temperature must not exceed the T ambient rating of +60°C (+140°F).
All sample 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 ttings are twin ferrule compression type. All electrical and liquid connections are made through the base of the enclosure. Refer to the Mounting Drawing in Appendix A.1.
Flow components for Channels 1 & 2 comprise the following:
Flow Meter: Provides indication of low, OK or high fl ow that is present
throughout the sample measurement stream.
Measurement Cell: The point of measurement that incorporates the Michell Ceramic
Moisture Sensor.
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INTRODUCTION
1.3 Operating Overview
The system continually measures moisture and temperature in an uninterrupted liquid sample fl ow rate. Moisture content is determined in part per million by weight (ppm through Henry’s Law, from the measured dew-point temperature and liquid temperature. It uses an extensive list of saturation concentration data pre-programmed for a variety of petrochemical liquids, with provision for easy entry of ‘custom’ characteristics data by the user.
Moisture and temperature for each channel are logged at a user-defi ned 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 humidity and temperature in real time.
1.4 User Display and Interface
The Liquidew 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.
Liquidew EExd User’s Manual
W
)
1.5 Advanced Sensor Technology
Liquidew EExd utilizes the Michell Ceramic Moisture Sensor, an advanced impedance sensor technology, with integrated temperature measurement. This sensor is used in more than 1,000 natural gas and petrochemical installations worldwide.
Semiconductor thick- and thin-fi lm technologies combine in metallized ceramics, producing an exceedingly durable sensor with the physical resilience to provide long­term reliable service in liquid phase measurements.
The Ceramic Sensor responds to the partial pressure of water vapor in the fl uid being measured, which is directly related to the dew-point temperature. Every Liquidew EExd sensor is calibrated against fundamental dew-point measurement systems in Michell’s laboratory, which is internationally accredited and directly traceable to both NPL(UK) and NIST(USA) metrology standards.
1.6 Measurement Units
The hygrometric unit can be set by the user to °C/°F dew point or moisture content in
.
ppm
W
The advanced fi rmware of the Liquidew EExd provides moisture measurements in ppm through the application of Henry’s Law. It uses pre-programmed saturation concentration (Cs) values for the following common pure hydrocarbon liquid applications:
W
Hexane, Propane, Isopropylbenzene, Benzene, Butane, Isobutane, Propylene, Cyclohexane, 1-Butene and Octene. See Appendix B for instrument display names.
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Liquidew EExd User’s Manual
Four user-programmable tables enable the Liquidew EExd to be applied to virtually any immiscible solute. For simple mixtures of hydrocarbons, a proportional combination of the Cs values for two or three individual substances can be applied, although with increased measurement uncertainty. For applications with complex mixture fl uids, customers can enter their own Cs values (in ppm (+32 to +122°F)) from their own library sources or from actual laboratory titration analysis of the fl uid concerned.
1.7 Elimination of Temperature Effects
To ensure continuous optimum analysis conditions the Liquidew 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 otherwise induce transitional adsorption and desorption effects of the fl owing sample and result in erroneous measurements.
In addition, the Liquidew EExd features 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.
INTRODUCTION
for temperatures from 0 to +50°C
W
1.8 Calibration
Maintenance of calibration is essential to the lifetime performance of all analyzers. To ensure that all customers worldwide can maintain the performance of their Liquidew EExd, the unique Michell Calibration Exchange Service offers freshly calibrated replacement Ceramic Sensors certifi ed traceable to NPL and NIST. The calibration characterization data for each Liquidew EExd Sensor is programmed into on-board non-volatile memory. Fitting the Calibration Exchange Sensor refreshes the calibration, returning the measurement performance to day-one. This takes only a few minutes of downtime while the interchange is made. No programming or data input is required by the user to complete this.
The calibration exchange is available globally, typically taking less than two weeks, with comparable cost of a traditional ‘return to manufacturer’ re-calibration service.
The recommended calibration maintenance interval is 12 months.
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INTRODUCTION
1.9 Liquidew EExd Sampling System
(Optional – see separate manual if you have purchased this item)
Liquidew EExd User’s Manual
Figure 1
Good sample conditioning and handling is particularly important in the fi eld 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 Liquidew EExd Sampling Systems. Contact Michell Instruments for further details: www.michell.com.
Liquidew EExd Sampling System
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Liquidew EExd User’s Manual
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2 INSTALLATION
2.1 Electrical Safety
During the installation of this product ensure that all
applicable national and local electrical safety regulations
Always ensure that power is switched off prior to accessing the product for any purpose other than normal operation or
INSTALLATION
WARNING:
are observed.
WARNING:
Isolate the power prior to installation.
WARNING:
prior to disconnecting any cables.
2.1.1 Equipment Ratings and Installation Details
The mandatory statements contained within refer to the Ex certifi ed Liquidew 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 180W.
The power is connected via PL1 on the mains connector PCB.
Figure 2
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.
Power Connection Connector
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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 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
Liquidew EExd User’s Manual
. Ensure the power supply can deliver suffi cient
Figure 3
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 Specifi cation, 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.
Earthing Stud And Nut Washer Assembly
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Liquidew EExd User’s Manual
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 specifi ed 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.
INSTALLATION
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Page 16
INSTALLATION
!
2.2 Hazardous Area Safety
Refer to Appendix H for the Hazardous Area Certifi cation of this product.
This product is fi tted 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.
This product is certifi ed safe for use in a Zone 1 and Zone 2
area only. This product must not be installed or used within
Liquidew EExd User’s Manual
WARNING:
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 (-40 to +140°F).
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.
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Liquidew EExd User’s Manual
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!
!
2.3 Pressure Safety
This product is used in conjunction with pressurized gases.
Observe pressurized gas handling precautions.
Pressurized gas should only handled by suitably trained
INSTALLATION
WARNING:
WARNING:
Pressurized gas is dangerous.
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
Personnel must observe suitable lifting and handling
This product is not designed as portable or transportable equipment. It should be rigidly xed in position as per the full installation instructions.
The weight of the analyzer is in excess of 18kg (40lbs). 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.
WARNING:
This instrument is in excess of 18kg (40lbs).
precautions.
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 fi xing 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).
Liquidew EExd User’s Manual
245mm 9.65"
355mm [13.9"]
1/8" NPT Female (ATEX/IECEx/CSA)
Sample out - Channel 1
1/8" NPT Female (ATEX/IECEx/CSA)
290mm [11.41"]
Sample in - Channel 1
Flame Arrestor
Flame Arrestor
270mm 10.63"
310mm [12.20"]
4 o M12 (1/2") Clearance
318mm 12.52"
Enclosure Breather Flame Arrestor Do NOT obscure
Sample in - Channel 2 (Optional) Flame Arrestor
1/8" NPT Female (ATEX/IECEx/CSA)
Sample out - Channel 2 (Optional) Flame Arrestor
1/8" NPT Female (ATEX/IECEx/CSA)
Cable Entry Glands 3 o M20 (ATEX) 3 o 1/2" NPT (CSA)
Figure 4
Liquidew EExd Dimensions
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Liquidew EExd User’s Manual
2.5.1 Pipework
INSTALLATION
MICHELL MOISTURE
SENSOR
h
FLAME
ARRESTOR
SAMPLE IN SAMPLE OUT SAMPLE IN SAMPLE OUT
h
SAMPLING BLOCK
FLOW METER
CHANNEL 1
FLAME
ARRESTOR
MICHELL MOISTURE
h
FLAME ARRESTOR BREATHER
h
ARRESTOR
FLAME
{
SENSOR
FLOW METER
h
h
SAMPLING BLOCK
ARRESTOR
CHANNEL 2
OPTIONAL
h
FLAME
{
Figure 5
NOTE: Ensure that the process sample gas supply line is well fl ushed through to clear any debris present, prior to connection to the instrument. A sample handling system must prepare the liquid in terms of fi ltration and temperature reduction (if greater than +40°C (+104°F) before entering into the measurement system.
In accordance with the Certifi cation requirements, the Liquidew EExd must have, as a minimum, those components described in the Sample System Flow Diagram shown in
Figure 6.
The pipework connections are:
Moisture Channel 1 Sample inlet
(Maximum pressure of 50 barg (725 psig))
Moisture Channel 1 Sample outlet Moisture Channel 2 Sample inlet
(Maximum pressure of 50 barg (725 psig))
Moisture Channel 2 Sample outlet
Pipework Connections
1/8" NPT(F)
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Page 20
INSTALLATION
The following points should be considered when installing the sample liquid 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.
Filtration is critically important to avoid particulate contamination. For process fl uids with high levels of particulates present, two-stage fi ltration may be required.
For elevated temperature processes, the sample fl ow temperature should be moderated, preferably to less than +40°C (+104°F) (max. +60°C (+140°F)), prior to entering the Liquidew EExd Main Unit.
There should be suffi cient differential pressure between sample source and return points to enable a fl ow of between 0.1 and 0.3 l/min (0.03 and 0.08 GPM) through the analyzer.
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.
Liquidew EExd User’s Manual
Piping should be lagged and/or trace heated if ambient temperatures could cause the sample liquid to fall below its saturation temperature.
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.
2.5.2 Power Connections
A single-phase AC power connection is required.
The power supply can accommodate voltages from 90 to 260 V AC, 47/63 Hz. The unit requires a maximum of 180W to function correctly.
The connection is made via a two-part connector mounted at the base of the unit. See Appendix A.
Cable entry into the measurement system is made through the bottom of the enclosure.
For ATEX/IECEx compliant versions of the product, 3 off ISO M20 tapped holes are provided.
For cCSAus compliant version of the product, 3 off ½” NPT entries are provided.
NOTE: EExd Stopping Glands MUST be used for ATEX/IECEx installations. Refer to the separate installation & maintenance information sheet supplied.
The terminals are marked:
L = Live N = Neutral E = Earth
12 97097 Issue 13.1, July 2018
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Liquidew EExd User’s Manual
AL3AL2AL1 AL4 COMMS Channel 1 Channel 2
PL16
NC C NO NC C NO
7891011
h
12
NC C NO NC C NO
123456
INSTALLATION
Optional
{
mA1+
mA1-
mA2+
B A GND
13 14 15
PL20 PL15 PL14 PL19
16 17 18 19 20 21 22 23
mA2-
LEN
mA3+
mA3-
mA4+
mA4-
Enclosure wall
Figure 6
2.5.3 Analog and Digital Communications
Two active 4-20 mA outputs and a Modbus RS485 digital interface (see Appendix F for details) are provided with the Liquidew EExd. mA1 and mA3 output the moisture or dew-point values. mA2 and mA4 output the sample temperature values of Channels 1 & 2 respectively.
NOTE: The maximum output resistance for the 4-20 mA outputs is 500Ω.
See Section 3.7 on the setting of the 4-20 mA outputs via the user interface and Appendix F on setting the outputs via the Modbus interface.
Refer to
Figure 7
for cable wiring.
Hook-up Wiring Diagram
h
h
Gland
Cable screen
2.5.4 Process Alarms and Analyzer Status Alarms
Each channel has an associated process and fault alarm, as shown below:
AL1: Channel 1 process alarm AL2: Channel 1 analyzer status alarm AL3: Channel 2 process alarm (Optional) AL4: Channel 2 analyzer status alarm (Optional)
The process alarm contacts can be set as either Normally Closed ( Open (
The process alarm contacts change from
N/O).
N/C to N/O when the moisture value becomes
N/C) or Normally
greater than the alarm set point.
The fault alarm contacts change from
N/C to N/O when an error associated with the
channel occurs or when there is a supply failure.
Michell Instruments 13
Page 22
INSTALLATION
!
Liquidew EExd User’s Manual
2.6 Liquidew EExd Start-up Purge Procedure
This is a mandatory procedure stipulated in the ATEX/IECEx
certifi cation of the product. The procedure must be fully carried out prior to the Liquidew EExd having any power or signal connections applied. It must also be fully carried out
after the Liquidew EExd and associated sample handling
equipment has been installed and leak checked. Always refer
to Appendix H.4 - Special Conditions of Safe Use.
This procedure must be carried out at any time following
service or maintenance periods that cause any of the
Liquidew EExd or associated sample handling equipment
pipe work to be disconnected.
It is not necessary to carry out this procedure if power or
signal connections only have been disconnected.
1. Before start-up ensure that all power and signal connections to the Liquidew EExd are fully isolated.
2. Ensure that all Inlet & Outlet liquid connections to the Liquidew EExd are made correctly and are leak tight checked.
3. Fully open the sample Inlet & Outlet isolation valves.
4. Allow the sample to purge the system for the period of time indicated in the table below:
TOTAL PURGE TIME
must be a minimum of 1 minute at 1 l/min (0.26 GPM)
Assumes total system pipe length is 3m (9.8') and internal pipe bore is the
recommended 4mm (0.16") internal bore.
For every additional 1m (3.3’) of pipe work, continue the sample purge for
an additional 15 seconds at 1 l/min (0.26 GPM).
5. After the appropriate purge duration, close the sample Inlet & Outlet isolation valves.
6. Ensure the window is replaced and fully secured before applying the power.
14 97097 Issue 13.1, July 2018
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Liquidew EExd User’s Manual
MINIMUM REQUIREMENTS FOR START UP PURGING
INSTALLATION
INLET
NEEDLE VALVE
SAMPLE
INLET
INLET
NEEDLE VALVE
SAMPLE
INLET
Figure 7
2.7 Sample Flows
The fl ow meter provides the user with an indication of the sample fl ow status via a message displayed on the STATUS Page. The three states available are
HIGH fl ow.
X
CHANNEL 1
X
SAMPLE IN SAMPLE OUT
LIQUIDEW EExd
X
SAMPLE IN SAMPLE OUT
CHANNEL 2
X
Minimum Requirements for Start-up Purging
X
FLOW CONTROL
NEEDLE VALVE
X
FLOW CONTROL
NEEDLE VALVE
X
X
NON-RETURN
VALVE
SAMPLE
OUTLET
LOW, OK and
LOW Flow rate of <0.1 l/min (<0.03 GPM) OK Flow rate of between 0.1 and 0.3 l/min (0.03 and 0.08 GPM) HIGH Flow rate of >0.3 l/min (>0.08 GPM)
OK is the recommended setting during normal operation.
Michell Instruments 15
Page 24
OPERATION
3 OPERATION
3.1 System Operation
At switch-on, the instrument will display the MAIN Page. It will synchronise itself to the on-board real time clock, in order to begin logging data at the next minute that is a multiple of 5, i.e. 5, 10, 15 etc. The MAIN Page will show the moisture and temperature readings of either 1 or 2 sensors and a countdown to the time when it will take the next data log.
Figure 9
below shows the MAIN Page for both 1 and 2 sensor confi gurations.
Liquidew EExd User’s Manual
DEWPOINT
Figure 8
3.2 User Interface
3.9
0
Cdp
TEMPERATURE
0
Cdp
0
C
0
Cdp
0
C
0
C
25.4
TIME TO NEXT DATA LOG: 7m 45s
DEWPOINT CH1
4.6
25.5
DEWPOINT CH2
-3.9
24.5
TIME TO NEXT DATA LOG: 6m 45s
MAIN Page in Single Channel (top) and Dual Channel Modes
3.2.1 Interface Controls
Figure 10
illustrates the user interface. It has a vacuum fl uorescent display and four
touch sensitive pads that facilitate user interaction through the glass of the enclosure.
Liquidew EExd
Process Moisture Analyzer
DEWPOINT
3.9
TEMPERATURE
25.4
TIME TO NEXT DATA LOG: 7m 45s
j
Up/Down
Arrow
Buttons
0
Cdp
0
C
SELECT
j
SELECT
Button
Figure 9
j
j
MENU MAIN
jj
MENU/
MAIN
Button
User Interface
VFD Display
Blue LEDs
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Liquidew EExd User’s Manual
3.2.2 ‘Up/Down Arrow’ Buttons
OPERATION
Up () and Down () buttons are used to change pages, scroll through lists and
The adjust values.
3.2.3 ‘SELECT’ Button
Figure 10
Figure 11
Up/Down Arrow Buttons
SELECT
‘SELECT’ Button
SELECT button is used to select or de-select a highlighted item in a menu list.
The
3.2.4 ‘MENU/MAIN’ Button
The MENU/MAIN button is used to toggle between the MAIN Page and the MAIN MENU Page, or return to the MAIN Page from any location within the menu structure.
Figure 12
MENU
MAIN
‘MENU/MAIN’ Button
Michell Instruments 17
Page 26
OPERATION
3.3 Menu Structure
Liquidew EExd User’s Manual
Figure 14
Status Page
j
NO
below shows a map of the menu structure.
KEY
Main Menu
jj
SELECT
j
Error ?
YES
j
Error Report
Page
SELECT
j
SELECT
Choices
Menu Pages
Other Pages
STATUS
View
Logged
Data
SELECT
LOGGING
j
View
Statistics
SELECT
j
Page
1
Page
2
MENU
SELECT
System
Error Codes
View
Faults
SELECT
j
Logged
Start-Up
Banner
j
Main Page
MENU MAIN
j
VIEW/ADJ
VARIABLES
SELECT
j
Password
Page
NO
j
SELECT
j
Password
Correct?
YES
SENSOR
INFO
Press MENU/MAIN button to
get back to Main Page from
CONTACT
INFO
SELECT
SELECT
j
Sensor 1 Sensor 2
SELECT
j
Sensor 1
Info
SELECT
j
Sensor 2
Info
OPTIONAL
MENU MAIN
any location
MENU
MAIN
Contact/About
j
j
Page
1
j
j
j
Logged Pages
Page
2
Page
3
Variables Pages
j
j
Use Up/Down arrow buttons to scroll through menu items and pages
Figure 13
Menu Structure
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Liquidew EExd User’s Manual
3.4 MAIN MENU Page
This page is accessed by pressing the MAIN/MENU button from the MAIN Page. The instrument’s status, variables, logged data and system information are available through
this page. Use the press the
SELECT button to access.
Up () and Down () buttons to highlight the page of interest and
STATUS
LOGGING MENU VIEW/ADJ VARIABLES SENSOR INFO CONTACT INFO
OPERATION
MENU
3.5 STATUS Page
This page shows the status of the process alarm and fl ow for one or both channels depending upon the confi guration. When the measured moisture or dew-point value
rises above the alarm set-point, the alarm condition will be displayed as are shown as
meter.
Figure 14
LOW, HIGH or OK. See Section 2.7 for more information on the fl ow
MAIN MENU Page
ON. Flow rates
STATUS PAGE
CHN1 ALARM OFF CHN1 FLOW LOW
TIME TO NEXT DATA LOG: 2m 11s
Figure 15
STATUS Page
Press the MAIN/MENU button to return to the MAIN Page.
Michell Instruments 19
Page 28
OPERATION
3.6 LOGGING MENU Page
This page allows the viewing of data or statistical information on the logged data. Press
SELECT button to see the following options:
the
View Logged Data View Statistics View System Faults
Liquidew EExd User’s Manual
Press the pages. If there is no data available then access will be given to the other two options.
3.6.1 VIEW LOGGED DATA Page
This page allows access to the previous measurement results made by the instrument. A rolling total of a maximum of 150 samples can be logged, which represents a measurement history of 150 x (measurement time) in minutes. Sample 1 represents the most recent measurement taken. After 150 measurements have been logged, the oldest measurement will be deleted and replaced as each new measurement is logged.
Caution: Changing the moisture value, e.g. from dew point to moisture, will reset all the logged data and start a new fi le.
Access to each measurement sample is via the may be used to scroll through each page of information. If faster scrolling is required (to quickly move to another sample) press the will increase by 10. When the sample number selected is greater than that acquired, or is greater than 150, Sample 1 will be selected and displayed.
Up () and Down () buttons and the SELECT button to enter these options
Sample Number Time of Sample
j j j
No Data Available will be displayed and no
Up () and Down () buttons, which
SELECT button and the sample number
Date (day/month)
LOGGED DATA
NO. 1 11:40 03/09
MOIST -3.6 oCdp TEMP 25.0
Figure 16
Each page of logged data contains:
Sample number 1 to 150, 1 being the most recent
Date of sample dd/mm
Time of sample 24 hr format, hh:mm
Values Moisture content/dew point and
Units of measurement °C / °F or ppm
LOGGED DATA Page
temperature for 1 or 2 channels
o
C
W
Press the MAIN/MENU button to return to the MAIN Page.
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Liquidew EExd User’s Manual
3.6.2 VIEW STATISTICS
These pages display the maximum, minimum and average values for each measured parameter for up to 150 previous measurement samples. MENU Page re-sets the logging statistics.
STATISTICS PAGE 1/2
MOIST MAX -3.6 oCdp at 11:40 on 03/09
MOIST MIN -3.6 at 11:40 on 03/09
OPERATION
RESET LOG on the MAIN
o
Cdp
MOIST AVR -3.6
Figure 17
Use the Up () and Down () buttons to scroll through the statistics.
Press the
3.6.3 VIEW SYSTEM FAULTS Page
This page displays a record of the last six system faults that have occurred and have subsequently been corrected. This assists in the diagnosis of any past anomaly in measured values. Any present system faults will be displayed in the bottom message line of the MAIN Page.
MAIN/MENU button to return to the MAIN Page.
LOGGED ERROR CODES
CODE TIME & DATE
0008 11:10 02/08/12
o
STATISTICS Page
Cdp
Figure 18
Refer to Section 4.4 for descriptions of the error messages and codes.
Press the
MAIN/MENU button to return to the MAIN Page.
SYSTEM FAULTS Page
Michell Instruments 21
Page 30
OPERATION
3.7 VIEW/ADJ VARIABLES Page
For more information on each variable refer to Appendix B.
3.7.1 Password
To safeguard against unauthorized adjustment of set-up parameters and variables, an entry lock is provided.
The user must fi rst input the access code to enter the VIEW/ADJUST VARIABLES Pages.
The password is 7316.
ENTER PASSWORD
USE ARROW KEYS AND SELECT KEY
Liquidew EExd User’s Manual
0 0 0 0
Use the Up () and Down () buttons to change the highlighted digit and press the
SELECT button to enter and move to the next digit. Inputting 4 correct digits will result
in access to the Variables Pages as detailed in the following sections.
3.7.2 VARIABLES Pages
Three pages (four pages in the dual channel confi guration) are used to display the system variables. They can be adjusted by using the Up (), Down () and SELECT
buttons.
Use the To select a variable for adjustment, scroll to the desired variable and press the button the Up () and Down () buttons to change the value. NOTE: Numerical values
can be changed at a faster rate by extending the duration of the
Up () and Down () buttons to scroll through the list and from page to page.
. A small box will appear beside the value to indicate that it can be adjusted. Use
Down () button press.
Figure 19
PASSWORD Page
VARIABLES PAGE 1/3 UNITS apply alarm OP1 MIN OP1 MAX OP2 MIN
Dew Point n/a 0
-100 20 0
o
C
o
C
o
C
o
C
SELECT
Up () and
Variables Page in single channel confi guration with Dew Point selected
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Liquidew EExd User’s Manual
VARIABLES PAGE 1/3 UNITS apply alarm OP1 MIN OP1 MAX OP2 MIN
Variables Page in single channel confi guration with Moisture & Solute Cumene selected
Moisture cumeme 0 PPM(W)
-100 20 0
PPM(W)
PPM(W)
o
C
OPERATION
Figure 20
3.7.3 Single Channel Confi guration Variables Pages
For more information on each variable refer to Appendix B.
Variables Page 1
Variable Brief Description
UNITS
apply
alarm
OP1min
OP1max
OP2min
Variables Page 2
Measurement, either moisture content or dew point When calculating moisture content, this variable is used to select the
sample solute type or user-defi ned solute Moisture content or dew-point value that trips the process alarm
Moisture content or dew-point value that gives 4 mA on mA1 output
Moisture content or dew-point value that gives 20 mA on mA1 output
Temperature value that gives 4 mA on mA2 output
VARIABLES Pages (Examples)
Variable Brief Description
OP2max
°C/°F
INT TEMP
TIME DATE
ADDR
Variables Page 3
Variable Brief Description
LOG INT’VAL
RESET LOG
SET DEFAULT
Temperature value that gives 20 mA on mA2 output
Temperature units selection
Set-point temperature of the internal heater
System time
System date
Sets the instrument address for serial communications
Time interval between data logs
Clears the logged data
Sets the system defaults
Michell Instruments 23
Page 32
OPERATION
3.7.4 Dual Channel Confi guration Variables Pages
For more information on each variable see Appendix B.
Variables Page 1
Variable Brief Description
Liquidew EExd User’s Manual
CHN1
apply
alarm
CHN2
apply
alarm
Variables Page 2
Variable Brief Description
OP1min
OP1max
OP2min
OP2max
OP3min
OP3max
Moisture content or dew-point value for Channel 1 When calculating moisture content, this variable is used to select the
sample solute type or user-defi ned solute for Channel 1 Moisture content or dew-point value that trips the process alarm for
Channel 1 Moisture content or dew-point value for Channel 2 When calculating moisture content, this variable is used to select the
sample solute type or user-defi ned solute for Channel 2 Moisture content or dew-point value that trips the process alarm for
Channel 2
Moisture content or dew-point value that gives 4 mA on mA1 output
Moisture content or dew-point value that gives 20 mA on mA1 output
Temperature value that gives 4 mA on mA2 output
Temperature value that gives 20 mA on mA2 output
Moisture content or dew-point value that gives 4 mA on mA3 output
Moisture content or dew-point value that gives 20 mA on mA3 output
Variables Page 3
Variable Brief Description
OP4min OP4max
°C/°F
INT TEMP
TIME
DATE
Variables Page 4
Variable Brief Description
INST ADDR
SET DEFAULT
LOG INT’VAL
RESET LOG
Temperature value that gives 4 mA on mA4 output
Temperature value that gives 20 mA on mA4 output
Temperature units selection
Set-point temperature of the internal heater
System time
System date
Sets the instrument address for serial communications
Sets the system defaults
Time interval between data logs
Clears the logged data
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Liquidew EExd User’s Manual
3.7.5 User-Defi ned Solutes
When selecting the sample solute type it is also possible to select up to four different user-defi ned solutes, labelled by default as U1, U2, U3 and U4. These are available by scrolling through to the end of the list of sample solute types. The table of saturation constants (or Cs values) of each user-defi ned solute can be edited by the user. From the Variables page, to edit your solute, scroll down the solute list and choose one of the user-defi ned solutes. Select the solute and it will show the the Cs value editor page. Each user-defi ned solute may also be given a customized label which will be appended to the end of the default labels.
3.7.5.1 Editing the Table of Cs Values
Variable Brief Description
OPERATION
0°C 10°C 20°C 30°C 40°C 50°C
To view the table of Cs values, scroll to the desired user-defined solute using the
Cs Value at temp of 0°C
Cs Value at temp of 10°C
Cs Value at temp of 20°C
Cs Value at temp of 30°C
Cs Value at temp of 40°C
Cs Value at temp of 50°C
Up () and Down () buttons, press the SELECT button and the relevant table will
appear.
To edit any of the values use the the list. Scroll to the desired temperature and press the will appear beside the Cs value to indicate that it can be adjusted. Use the
Down () buttons to change the value - these can be changed at a faster rate by
and extending the duration of the arrow button press. Press the
nished and to adjust another value.
Press the
MENU/MAIN button to display the label editing page.
Up () and Down () buttons to scroll up and down
SELECT button. A small box
Up ()
SELECT button again when
3.7.5.2 Editing the Label for the User-defi ned Solute
The custom label can be up to 8 characters in length and consists of any combination of letters from A-Z, space, hyphen and numbers from 0 to 9.
To enter the page, press the Cs values. Use the
Up () and Down () buttons to select the character and press the
MENU/MAIN button from the page showing the table of
SELECT button to save and move to the next character position.
To exit back to Variables Page 1, press the
MENU/MAIN button.
Michell Instruments 25
Page 34
OPERATION
3.8 SENSOR INFO Page
This page contains the information relating to the water dew-point sensors.
Hours Used Duration that the sensor has been in active use
Liquidew EExd User’s Manual
SENSOR INFO
HOURS USED 00006 NEXT CAL 11/2012 SENSOR S/N FD79-0430
Figure 21
SENSOR INFO Page
Next Cal Next recommended calibration date of sensor
Sensor S/N Serial number of sensor
3.9 CONTACT INFO Page
This page contains contact information for Michell Instruments.
MICHELL INSTRUMENTS
WEB: WWW.MICHELL-INSTRUMENTS.COM E-MAIL: INFO@MICHELL-INSTRUMENTS.COM
CONTACT INFO
Figure 22
CONTACT INFO Page
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Liquidew EExd User’s Manual
DANGER
Electric
Shock Risk
!
4 MAINTENANCE
The power to the enclosure must be turned off before any
work is carried out in the measurement system enclosure.
Sample line connections to the measurement system must
be isolated and de-pressurized before any work commences.
Before powering up the instrument the “Start-up purge
procedure” must be carried out. See Section 2.6.
MAINTENANCE
Observe de-energize durations.
To ensure the full requirement of this product's safety
certifi cate is maintained, any loosened or disturbed tubework
or couplings must be subject to a gas pressure test and
appropriate leak check at 1.5x the max operating pressure
before the full product is re-energized.
The design of the Liquidew EExd sensor cell and measurement system is such that no specifi c routine maintenance is required. If, however, a fault does occur with your system that is not covered within this manual, please contact Michell Instruments (www. michell.com) or your local representative.
4.1 Enclosure Cover and User Interface
The enclosure cover is part of the fl ameproof protection for the enclosure and has an IP66 rating. It should be fi rmly closed to ensure fl ameproof integrity and continued environmental protection. For prolonged and easy operation ensure that the threads are always lubricated with a light grease. A grub screw is used as a locking device. This should be loosened before unscrewing the cover counter-clockwise.
The user interface assembly uses two ¼ turn bayonet style fasteners to secure it. These are fi nger operated and should be turned clockwise to lock and counter-clockwise to release. The user interface, once disconnected from the two ¼ turn fasteners, can be temporarily re-positioned on the instrument by securing the right-hand fastener in the left-hand mount. This will situate the interface assembly in an overhanging position outside of the enclosure allowing greater access. If there is insuffi cient space to accommodate the overhanging user interface assembly on the left-hand side, it may be rotated 180° (upside down) and placed on the right-hand side.
Michell Instruments 27
Page 36
MAINTENANCE
!
DANGER
Electric
Shock Risk
Liquidew EExd
Moisture in Liquid Analyzer
Liquidew EExd User’s Manual
Figure 23
Always keep the bayonet fi ttings lightly lubricated. If required, the user interface can be fully disconnected from the instrument by disconnecting the ribbon cable connection to the main processor PCB.
Unscrew the enclosure cover and remove the user interface
assembly before carrying out the procedures below.
Ribbon Cable Connection
4.2 Replacement of the Sensor Assembly
The power to the enclosure must be turned off before any work is carried out in the measurement system enclosure.
Observe de-energize durations.
1. Isolate the incoming sample line by CLOSING the sample inlet isolation valve and allow the system to depressurize and drain. Isolate the power and observe the de-energize duration.
2. Remove the enclosure window and mount the user interface (see Section
4.1).
3. Using a 2.5mm hex key, remove the M3 cap head screw (1 in securing the moisture sensor assembly to the stay bracket.
4. Restrain the sensor assembly. Using an 14mm wrench, loosen and remove the 2 off 6mm water dew-point sensor sample pipe connections (2 in
Figure 25)
.
Figure 25)
28 97097 Issue 13.1, July 2018
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Liquidew EExd User’s Manual
1
MAINTENANCE
2
Figure 24
5. Carefully pull the sensor block assembly out of the enclosure. This will allow access to the two sensor connections.
6. Disconnect the ribbon cable connectors from the sensor pcb.
7. Fully remove the sensor assembly from the enclosure.
8. Reconnect the sensor connections to the replacement moisture sensor assembly. Reposition the assembly on the stay bracket and secure with the M3 cap head screw.
9. Refi t and fully tighten the 6mm moisture sensor sample pipe connections.
10. To ensure the full requirement of this product's safety certifi cate is maintained, any loosened or disturbed tubework or couplings must be subject to a gas pressure test and appropriate leak check at 1.5x the max operating pressure before the full product is re-energized.
Moisture Sensor Assembly Replacement
Michell Instruments 29
Page 38
MAINTENANCE
DANGER
Electric
Shock Risk
3)
4)
4.3 Replacement of the Flow Meter
The power to the enclosure must be turned off before any work is carried out in the measurement system enclosure.
1
Liquidew EExd User’s Manual
Observe de-energize durations
2
Figure 25
1. Isolate the incoming sample line by CLOSING the sample inlet isolation valve and allow the system to depressurize. NOTE: Always refer to
Appendix H.4 - Special Conditions of Safe Use.
2. Remove the enclosure window and mount the user interface (see Section
4.1).
3. Restrain the fl ow meter assembly (1) and use a 14mm wrench to loosen and remove the 2 off 6mm sample pipe connections.
4. Unscrew the 2-wire cable connector (2) from the fl ow meter.
5. Carefully withdraw the fl ow meter assembly out of the enclosure.
6. Replacement of the fl ow meter is simply a reversal of the above procedure.
Flow Meter Replacement
7. To ensure the full requirement of this product's safety certifi cate is maintained, any loosened or disturbed tubework or couplings must be subject to a gas pressure test and appropriate leak check at 1.5x the max operating pressure before the full product is re-energized.
30 97097 Issue 13.1, July 2018
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Liquidew EExd User’s Manual
4.4 Troubleshooting
4.4.1 Error Messages
If a system errors occur, an error message will appear at the bottom line of the MAIN Page describing the problem. If more than one system error has occurred, the error messages associated with those faults will continually scroll in turn.
DEWPOINT
MAINTENANCE
3.9
0
Cdp
TEMPERATURE
55.4
TEMPERATURE OUT OF RANGE
Figure 26
Error Message Description and Possible Causes
DEWPOINT UNDER RANGE
DEWPOINT OVER RANGE
TEMPERATURE OUT OF
RANGE
LOW FLOW
HIGH FLOW
SATURATION
CAL TABLE ERROR
INTERNAL HEATER FAULT
Dew point <-120°C (<-184°F) or sensor tile failure
Dew point >+30°C (>+86°F) or sensor tile failure
Temperature >+50 or <0°C (>+122 or <32°F)
Flow through sensor measurement cell is <0.1 l/min (0.03 GPM) or fl ow meter has failed / disconnected
Flow through sensor measurement cell is >2.6 l/min (0.69 GPM)
Dew point is greater than or equal to temperature
Fault with sensor calibration data Internal temperature set-point not achievable or fault
with the internal temperature control devices
Error Message Line
0
C
4.4.2 Error Messages Flashing over Displayed Values
A short message will fl ash over the displayed value in the MAIN Page, in certain conditions, as indicated below:
Flashing Message Over Value Condition
error
error
under
over
error
Dew-point or
moisture content
Dew-point or
moisture content
Dew-point or
moisture content
Dew-point or
moisture content
Temperature
Moisture saturation condition (dew point temperature)
Calibration table error (checks sensor impedance values are increasing in the correct direction)
Dew point under range <-120°C (<-184°F)
Dew point over range >+30°C (>+86°F)
Sensor temperature fault <-40 or >+70°C (<-40 or >+158°F)
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MAINTENANCE
4.4.3 Logged Error Codes
This page displays a record of the last six system error codes that have occurred in order to assist in the diagnosis of any past anomalies. Error codes are only logged at the end of every measurement cycle and indicate a change in status of single or multiple
errors. For example, if an error code
TEMPERATURE ERROR. If an error code of 0000 was logged next, this would indicate
that the error had now cleared.
Liquidew EExd User’s Manual
0004 was logged, this would indicate CHANNEL 1
LOGGED ERROR CODES
CODE TIME & DATE
0008 11:10 02/08/12
Figure 27
Logged Error Codes and Error Indication (Modbus Register 35)
Also see Appendix G, Register Confi guration C, for more details
Error Code
0000 0001 0002 0004 0008 0010 0020 0040 0080 0100 0200 0400 0800 1000 2000 4000
Error Relay Activated ?
NO All previous errors now cleared
YES Channel 1 dew-point sensor under range
YES Channel 1 dew-point sensor over range
YES Channel 1 temperature out of range
YES Channel 1 low fl ow
YES Channel 1 high fl ow
YES Channel 1 saturation condition
YES Channel 1 cal table error
YES Channel 2 dew-point sensor under range
YES Channel 2 dew-point sensor over range
YES Channel 2 temperature out of range
YES Channel 2 low fl ow
YES Channel 2 high fl ow
YES Channel 2 saturation condition
YES Channel 2 cal table error
NO Internal heater fault
Logged Error Codes
Error Condition
The 4-digit error codes are hexadecimal numbers that are dependent upon the bits set within the error indication register.
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Liquidew EExd User’s Manual
If more than one error has occurred, then the error codes will be added together:
MAINTENANCE
1 Error Code Error Code Error Code
2 Error Code Error Code Error Code
Note: In hexadecimal:
A = 10 B = 11 C = 12 D = 13 E = 14 F = 15
4.4.4 Analyzer Fault Alarm Relay
The process alarm contacts can be set as either Normally Closed (N/C) or Normally Open (
N/O).
0104 = 0100 (Channel 2 dew-point sensor over range) plus 0004 (Channel 1 temperature out of range) (0100 + 0004 = 0104)
0C00 = 0800 (Channel 2 high ow) plus 0040 (Channel 1 cal table error) (0800 + 0400 = 0C00)
The process alarm contacts change from greater than the alarm set point.
The fault alarm contacts change from channel occurs or when there is a supply failure.
N/C to N/O when the moisture value becomes
N/C to N/O when an error associated with the
Michell Instruments 33
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APPENDIX A
Liquidew EExd User’s Manual
Appendix A
Technical Specifi cations
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Liquidew EExd User’s Manual
Appendix A Technical Specifi cation
Main Unit – Measurement Parameters
Channel Confi guration Single and dual channel Moisture Content ppm Temperature °C and °F Water Dew Point °C and °F
Sample Flow Rate
Sensor Technology
Moisture Sensor Technology
Calibration Range -100 to +20°Cdp ( -148 to +68°Fdp) Measurement Range -120 to +30°C (-184 to +86°F) (0.001 ppm Accuracy
Dew point:
Moisture content:
Analysis temperature:
Resolution
Temperature Coeffi cient Algorithm compensation Operating Pressure Max. 50 barg (725 psig)
Sample Flow
W
Status indication: LOW/OK/HIGH <0.1 to >0.3 l/min (<0.03 to >0.08 GPM)
Michell Ceramic Moisture Sensor
±1°C between –59.9 & +20°Cdp (±1.8°F between -75.9 to +68°Fdp) ±2°C between –60 & -100°Cdp (±3.6°F between -76 to -148°Fdp) ±10% of reading ±20% of reading Accuracy ±0.2°C
0.1°C between +20 & -80°Cdp (0.2°F between +68 & -112°Fdp) 1°C between -80 & -100°Cdp (2°F between -112 & -148°Fdp)
Up to 1 Nl/min (0.1 to 0.2 Nl/min recommended) (Up to 0.26 GPM (0.03 to 0.05 GPM recommended))
APPENDIX A
to saturation)
W
HMI
Keypad/Interface Capacitive touch-screen through glass Display Vacuum fl uorescent
A rolling maximum of 150 data logs is available Each log records time, date, moisture and temperature values for
Datalogging
Communications and Output
each channel 5 minutes minimum and 60 minutes maximum logging intervals can be set by the user
Two non-isolated 4-20 mA per measurement channel 500 maximum load Range and parameter settable by user Modbus RTU @ 9600 baud-rate Alarms: two volt free contacts per channel; one process value and one instrument status Also available via Modbus communications
Enclosure
Type Flameproof EExd Construction Cast copper-free aluminum
Finish
Chromate primer, Polyester P9010 powder coated (black) - meets BS3900
Michell Instruments 35
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APPENDIX A
Liquidew EExd User’s Manual
General
Sample Connections 1/8" NPT(F) Weight 21kg (46lbs) Operating Supply Voltage 90 to 260 V AC, 47/63 Hz, 180 W - Main Unit
Operating Environment
Indoor/Outdoor -20 to +60°C (-4 to +140°F) Max 95%RH
Hazardous Area Certifi cation
ATEX II 2G Ex d IIB + H2 Gb T5 (-40°C to +44°C)
T4 (-40°C to +60°C)
Certifi cation Codes
Pattern Approvals GOST-R, GOST-K
IECEx Ex d IIB + H2 Gb T5 (-40°C to +44°C) T4 (-40°C to +60°C)
cCSAus Class I, Division 1, Group B, C, D, T4 Tamb -40°C to +60°C TC TR Ex 1Ex d IIB + H2 T4, T3 Gb (-40°C to +60°C)
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A.1 Mounting Drawing
APPENDIX A
245mm 9.65"
355mm [13.9"]
1/8" NPT Female (ATEX/IECEx/CSA)
Sample out - Channel 1
1/8" NPT Female (ATEX/IECEx/CSA)
290mm [11.41"]
Sample in - Channel 1
Flame Arrestor
Flame Arrestor
270mm 10.63"
4 o M12 (1/2") Clearance
318mm 12.52"
Enclosure Breather Flame Arrestor Do NOT obscure
Sample in - Channel 2 (Optional) Flame Arrestor
1/8" NPT Female (ATEX/IECEx/CSA)
Sample out - Channel 2 (Optional) Flame Arrestor
1/8" NPT Female (ATEX/IECEx/CSA)
Cable Entry Glands 3 o M20 (ATEX)
310mm [12.20"]
3 o 1/2" NPT (CSA)
Figure 28
Mounting Drawing
Michell Instruments 37
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APPENDIX A
A.2 Pipework Connections
Liquidew EExd User’s Manual
h
SENSOR
MICHELL MOISTURE
SAMPLING BLOCK
FLOW
METER
h
h
h
FLAME
FLAME
ARRESTOR
ARRESTOR
{
OPTIONAL
CHANNEL 2
FLAME
BREATHER
ARRESTOR
h
FLAME
ARRESTOR
h
SAMPLING BLOCK
FLOW
METER
h
SENSOR
FLAME
MICHELL MOISTURE
ARRESTOR
{
CHANNEL 1
SAMPLE IN SAMPLE OUT SAMPLE IN SAMPLE OUT
Figure 29
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Pipework Connections
Page 47
Liquidew EExd User’s Manual
!
A.3 System Wiring Diagram
APPENDIX A
NC C NO NC C NO
123456
Enclosure wall
NC C NO NC C NO
PL16
Optional
AL3AL2AL1 AL4 COMMS Channel 1 Channel 2
mA1+
mA1-
mA2+
7891011
h
B A GND
12
PL20 PL15 PL14 PL19
13 14 15
16 17 18 19 20 21 22 23
LEN
mA2-
h
h
mA3+
Gland
mA3-
mA4+
{
mA4-
Figure 30
System Wiring Diagram
EExd Stopping Glands MUST be used for ATEX/IECEx
installations.
Refer to the separate installation & maintenance
information sheet supplied.
Michell Instruments 39
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APPENDIX B
Liquidew EExd User’s Manual
Appendix B
Variable Defi nitions
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Liquidew EExd User’s Manual
Appendix B Variable Defi nitions
From the Variables Page, press the Up () or Down () buttons to highlight the variable required. Press the SELECT button to enter the range/options area. Change the variable using the
the new option. Scroll down to the next variable required. To return to the MAIN Page press the MENU/MAIN button.
Variable: Adjustable Range/Options: DEW POINT, MOISTURE
Description: The display units for Channels 1 and 2.
Up () or Down () buttons and press the SELECT button to set
CHN1, CHN2
APPENDIX B
i. When
enabled to allow the selection of the sample Solute.
ii. mA1 and mA3 outputs represent the setting of Channels 1
& 2 respectively.
NOTE: Changing the units clears the data logging memory and resets the
analog outputs and alarm settings
Variable: Adjustable Range/Options: Range of 10 pre-set sample solutes and 4 user-defined
apply
MOISTURE is selected, the apply option below is
sample solutes
Description: The following samples are available for selection when MOISTURE is
selected for Channels 1 and 2.
Common Name Displayed Name
Hexane n-hexane
Propane n-propane
Isopropylbenzene cumene
Benzene benzene
Butane n-butane Isobutane 1-butane Propylene prop-1-ene
Cyclohexane cyclohexane
1-Butene but-1-ene
Octene oct-3-ene
User-defi ned solute 1 U1 User-defi ned solute 2 U2 User-defi ned solute 3 U3 User-defi ned solute 4 U4
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APPENDIX B
Variable: alarm Adjustable Range/Options: -100 to +20°C for Dew point, 0 to 5000 PPM(W) for
Description: The set-point for the process alarm that activates the channel alarm relay
Liquidew EExd User’s Manual
Moisture
when the moisture value exceeds it.
Variable: Adjustable Range/Options: -100 to +20°C for Dew point, 0 to 5000 PPM(W) for
OP1min, OP3min, OP1max, OP3max
Moisture
Description: OP1min and OP3min are the moisture values that 4 mA represents for the
respective output. OP1max and OP3max are the moisture values that 20 mA represents for the respective output.
Variable: Adjustable Range/Options: 0 to +70°C for temperature
Description: OP2min and OP4min are the moisture values that 4 mA represents for
Variable: Adjustable Range/Options: -20.00 to +60.00°C
OP2min, OP4min, OP2max, OP4max
the respective output. OP2max and OP4max are the moisture values that 20 mA represents for the respective output.
INT TEMP SP
Description: Sets the set-point for the internal heater.
Variable: Adjustable Range/Options: Celsius, Fahrenheit
Description: Dew point and temperature unit of measurement in °C or °F
Note: Changing temperature units will set the default values and clear
Variable: Adjustable Range/Options: hh:mm; 00:00 to 23:59
Description: The real-time clock in 24hr format. Minutes and hours may be adjusted.
°C / °F
the logged data
TIME
Pressing either the decrement the minute fi eld and the corresponding hour fi eld will change accordingly and automatically.
Up () or Down () button will increment or
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Variable: DATE Adjustable Range/Options: Day: 01-31, Month: 01-12, Year: 00-99
Description: The date. Format: ddmmyy. To adjust the day, highlight the DATE fi eld,
press
SELECT (a ‘d’ should appear to the right of the year value). Use the
Up () or Down () buttons to adjust. To adjust the month and year,
press
SELECT again (an ‘m’ should appear to the right of the year value).
Use the changes, the year fi eld will change accordingly and automatically. Press
SELECT to nish.
Up () or Down () buttons to adjust the month. As the month
APPENDIX B
Variable: Adjustable Range/Options: 01 to 31
Description: Unique instrument address for networking. This address is used by the
Variable: Adjustable Range/Options: NONE
Description: Sets instrument to default confi guration. The default values for all the
Variable: Adjustable Range/Options:
INST ADDR
Modbus protocol to specify the location of the Liquidew EExd instrument in the network.
SET DEFAULT
variables and parameters are set. To initiate, select the variable and then press either the
Up () or Down () button.
LOG INT’VAL
10 to 60 in intervals of 10 minutes
Description: Sets the interval between the logged data readings.
Variable: Adjustable Range/Options: select, done
Description: Resets the logging statistics so that the variation in measurements can be
RESET LOG
recorded from a user-defi ned start point. When the is highlighted press the
SELECT button - the option will go from select to
RESET LOG variable
done.
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APPENDIX B
Variable: CS VALUES Adjustable Range/Options:
Description: The Cs Values available to adjust or view in the user-defi ned Cs table
Liquidew EExd User’s Manual
0 to 5000 PPM(W)
pages.
Variable: Adjustable Range/Options: A to Z, hyphen, space, 0 to 9
Description: Characters that make up the user-defi ned solute custom label.
The default values are:
User-defined Solute CUSTOM LABEL CHAR
CHN 1 / 2
Apply Alarm
OP1 Min
OP1 Max
OP2 Min
OP2 Max
OP3 Min
OP3 Max
OP4 Min
OP4 Max
°C / °F
Int Temp
Cs Values
User Solute Labels
Dew point
N/A
0°C
-100°C (-148°F)
+20°C (+68°F)
0°C (+32°F)
+70°C (+158°F)
-100°C (-148°F)
+20°C (+68°F)
0°C (+32°F)
+70°C (+158°F)
Celsius
+20°C (+68°F)
00
U1 U2 U3 and U4
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APPENDIX C
Appendix C
Software
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APPENDIX C
Appendix C Software
Software is available for the Liquidew EExd to provide full remote control of up to 31 instruments. It provides access to all readable and write-able registers as described in Appendix E along with charting and data logging facilities.
The Liquidew EExd application software provides the user with advanced acquisition, logging and charting features for full remote control and monitoring of the Liquidew EExd.
With this application software it is possible to:
View all main parameters of interest
• Modify parameters
Record parameters to a virtual chart recorder
Record parameters to a fi le
Liquidew EExd User’s Manual
Acquire data from up to 31 process instruments
Perform remote diagnostics
Acquire OPC enabled remote access to all parameters and variables
C.1 System Requirements
For a desktop computer, the following specifi cation applies:
Microsoft Windows 7, 98SE, ME, 2000 or XP operating system
Spare RS232 port (normally labelled COM1, COM2 etc)
Minimum of 64 MB of RAM (128M or higher recommended)
Minimum of 200 MB of free hard disk space (application approximately 3.5 MB, spare for log fi les)
Intel Pentium II class processor, 200 MHz or higher
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APPENDIX D
Appendix D
Calibration Correction
Michell Instruments 47
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APPENDIX D
Appendix D Calibration Correction
D.1 Overview
The Liquidew EExd is delivered with a Calibration Certifi cate detailing the deviation at each measurement point from a known reference value. Data provided on the Calibration Certifi cate is normally arranged as shown in the following extracts:
Extract from a UKAS Calibration Certifi cate:
Liquidew EExd User’s Manual
Generated
Dew point
°C
-39.89 -40.11 +0.22 ±0.26
-20.10 -20.31 +0.21 ±0.22
0.39 0.20 +0.19 ±0.18
Extract from a Standard Calibration Certifi cate:
Dew-point
Temperature
°C
Generated
Dew point
°C
-40.1 -40.2
-20.1 -20.1
0.2 0.1
Test Hygrometer
Correction
Required
°C
Instrument
Display
Expanded
Uncertainty
°C
°C
From time to time the Liquidew EExd may be calibrated by an external calibration agency, and similar data will be provided.
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D.2 Calibration Software
A calibration correction utility has been integrated into the Process Application Software. This allows authorized users to input calibration information in order to effect a real­time correction of the displayed dew point. This software facilitates the uploading and downloading of the instrument's calibration via the Modbus RTU interface.
The fi gure below shows the Calibration Correction window; two sets of data may be entered:
Ref DP Dew-point data for the reference hygrometer
• (sometimes called the actual dew point or the standard)
Liquidew DP Measured dew-point value of the Liquidew
• under test
Data can be entered for 13 calibration points between +20 and -100°Cdp (+68 and
-148°Fdp). However, if no data is available then the
remain equal and be exact for the calibration point as shown in the fi gure below.
APPENDIX D
Ref DP and Liquidew DP should
Cal point Ref Dp Liquidew Dp
Figure 31
Calibration Correction Data
NOTE: The fi gure above shows calibration data for -20 to –40°Cdp only. The Ref Dp and Liquidew Dp are equal for points where no calibration data is available.
Michell Instruments 49
Page 58
APPENDIX D
!
D.3 Calibration Procedure
be done by a recognized humidity calibration laboratory
accredited by a standards institution such as UKAS or NIST.
1. Press the Get Table button to download the correction table for either
Channel 1 or 2 and check to see if the values are equal and exact. If not, then the instrument has had its calibration adjusted previously. To simplify the correction procedure, reset the adjusted values back to their ‘equal & exact’ default values.
2. Connect the Liquidew EExd to a suitable dew-point generator with a
reference hygrometer (preferably chilled-mirror type with traceable calibration). Purge the Liquidew for a minimum of 5 days with air that is drier than -100°Cdp (-148°Fdp) before commencing the calibration.
3. Increase the generator set-point in steps of 10°Cdp (18°Fdp), moving
sequentially up the Liquidew’s measurement range from –100 to +20°Cdp (-148 to +68°Fdp) and record the dew point measured by the reference and the Liquidew.
Liquidew EExd User’s Manual
Caution: A valid correction of the calibration can only
Any calibration performed by an unrecognized body will
invalidate the calibration of the instrument.
Suitable stabilization periods should be allowed between changing the generator setting and taking the fi nal sensor count and reference hygrometer values. Actual stabilization times will depend to a degree on the type of generator used, the gas fl ow rate and the integrity of the pipe work and sensor manifold. As a rule of thumb, it is strongly suggested that the following stabilization times are taken as a minimum requirement:
Dew-point Temperature
°Cdp
-100 5 days
-90 12 hours
-80 10 hours
-70 8 hours
-60 4 hours
-50 2 hours
-40 1 hour
-30 1 hour
-20 1 hour
-10 1 hour 0 1 hour
+10 1 hour +20 1 hour
If calibration is not being done to -100°Cdp (-148°Fdp) then the purge times can be reduced:
Minimum Stabilization Time
Drier than -70°Cdp (-94°Fdp) 5 days
-41 to -69°Cdp (-41.8 to -92°Fdp) 64 hours +20 to -40°Cdp (+68 to -40°Fdp) 16 hours
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The purge gas should be as dry as possible, ideally 10°Cdp (18°Fdp) drier than the driest dew point to be calibrated. The recommended stabilization times listed above should be followed when changing from one dew point to the next.
4. Enter the dew point values for the reference and the Liquidew that were recorded in item 1 above and leave the values 'equal and exact' for used calibration points.
APPENDIX D
5. To modify a data point, double click on the relevant cell and using the () and
as shown for the –60 calibration point in value will turn red to indicate its change of status.
6. After the data points have been changed press the to upload the data into the Liquidew.
Down () buttons adjust the value or enter the value directly,
Figure 32
. After amendment, the
Write new data button
Up
Michell Instruments 51
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APPENDIX E
Liquidew EExd User’s Manual
Appendix E
Modbus RTU
Communications
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Appendix E Modbus RTU Communications
E.1 Introduction
Implemented within the Liquidew EExd are Modbus RTU communications that enable remote access to the instrument's confi guration and data logging facilities. This protocol offers two-way communication between a PC or PLC known as the master, to one or more instruments known as slaves. Communication is achieved by the master reading or writing to registers within the slave. The slave acts upon information contained within the registers that can be written, and the master obtains measured values and status information from the register that can be read. Appendix E lists these registers and Appendix G specifi es the number or data formats that apply to each register.
E.2 Modbus RTU Basics
Modbus RTU operates on a Query-Response Cycle (see the diagram below). The function code in the query tells the addressed slave device which actions to perform using the information contained in the data bytes. The error check fi eld provides a method for the slave to validate the integrity of the message contents.
APPENDIX E
If the slave makes a normal response, the function code in the response is an echo of the function code in the query. The data bytes will contain data collected by the slave, such as register values or status information. If an error occurs, the function code is incremented by 80H. This indicates that the response is an error response, known as an exception, and the data bytes contain a code to describe the error. The error check eld allows the master to confi rm that the message contents are valid.
MASTER
Device Address
Function Code
E.3 Physical Layer
Data Bytes
CRC
Query Message from Master
Response From Slave
SLAVE
Device Address
Function Code
Data Bytes
CRC
The physical connection from the master to the Liquidew EExd uses 2-wire RS485 plus a ground connection. Data lines A, B and ground are connected to communication connectors within the instrument. The serial port protocol is as follows:
Baud Rate: 9600 Start Bit: 1 Data bits: 8 Parity: None Stop bit: 2
Michell Instruments 53
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APPENDIX E
E.4 Termination Resistor
A 120R termination resistor is provided on the instrument’s circuit board for systems that require it. To connect the resistor, place the link provided across JMP2.
E.5 Register Map
The following tables describe the instrument registers with their address location, Modbus function and the number format.
Liquidew EExd User’s Manual
Address
dec
0 0000* Instrument Address R/W F
1 0001 Sensor 1 Humidity Value – Hi Word (dp/moisture) R L
2 0002 Sensor 1 Humidity Value – Lo Word (dp/moisture) R L
3 0003 Sensor 1 Ambient Temperature R H
4 0004 Status R D
5 0005 Sensor 2 Humidity Value – Hi Word (dp/moisture) R L
6 0006 Sensor 2 Humidity Value – Lo Word (dp/moisture) R L
7 0007 Time to next log Mins + Secs R I
8 0008 Sensor 2 Ambient Temperature R H
9 0009 Sensor 1 Flow Reading l/min R F
10 000A Sensor 2 Flow Reading l/min R F
11 000B Sensor 1 Humidity Setting (dp or moisture) R/W B
12 000C* mA1 output maximum value (sensor 1 humidity) R/W K
13 000D* mA1 output minimum value (sensor 1 humidity) R/W K
14 000E* mA2 output maximum value (sensor 1
15 000F* mA2 output minimum value (sensor 1 temp) R/W M
16 0010* Sensor 2 Humidity Setting (dp or moisture) R/W B
17 0011* mA3 output maximum value (sensor 2 humidity) R/W F
18 0012* mA3 output minimum value (sensor 2 humidity) R/W K
19 0013* Logging Interval R/W I
20 0014* mA4 output maximum value (sensor 2 temp) R/W M
21 0015* mA4 output minimum value (sensor 2 temp) R/W M
22 0016* Sensor 1 Alarm Set Point R/W K
23 0017* Sensor 2 Alarm Set Point R/W K
24 0018* RTC Year (val1) + Month (val2) R/W I
25 0019* RTC Date (val1) + Hours (val2) R/W I
26 001A* RTC Mins (val1) + Secs (val2) R/W I
27 001B* Sensor 1 Solute Ref Number R/W H
28 001C* Sensor 2 Solute Ref Number R/W H
29 001D Units/ Command R/W E
30 001E Water DP Sensor 1 – Batch Number R I
31 001F Water DP Sensor 1 – Serial Number R I
32 0020 Water DP Sensor 1 - Year R I
33 0021 Water DP Sensor 1 – Month and day R I
34 0022 Water DP Sensor 1– Hours Of Operation R F
35 0023 Error Indicator R C
36 0024 Not Used
Address
hex
Function
Read/
Write
temp) R/W M
Default
Value
Register
Confi g- uration
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APPENDIX E
Address
dec
37 0025 Internal Temperature R A
38 0026 Internal Temp Set Point R/W A
39 0027 Water DP Sensor 2 – Batch Number R I
40 0028 Water DP Sensor 2 – Serial Number R I
41 0029 Water DP Sensor 2 - Year R I
42 002A Water DP Sensor 2 – Month and day R I
43 002B Water DP Sensor 2 – Hours Of Operation R F
44 002C Not Used
45 002D Humidity max – Hi Word – Sensor 1 R L
46 002E Humidity max – Lo Word – Sensor 1 R L
47 002F Occurred @ day (val1) + month (val2) R J
48 0030 Occurred @ hour (val1) + min (val2) R J
49 0031 Humidity min – Hi Word – Sensor 1 R L
50 0032 Humidity min – Lo Word – Sensor 1 R L
51 0033 Occurred @ day (val1) + month (val2) R J
52 0034 Occurred @ hour (val1) + min (val2) R J
53 0035 Humidity average Hi Word – Sensor 1 R L
54 0036 Humidity average Lo Word – Sensor 1 R L
55 0037 Not Used
56 0038 Not Used
57 0039 Instrument Type R I
58 003A Firmware Version Number R I
59 003B Not Used
60 003C Not Used
61 003D Humidity max – Hi Word – Sensor 2 R L
62 003E Humidity max – Lo Word – Sensor 2 R L
63 003F Occurred @ day (val1) + month (val2) R J
64 0040 Occurred @ hour (val1) + min (val2) R J
65 0041 Humidity min – Hi Word – Sensor 2 R L
66 0042 Humidity min – Lo Word – Sensor 2 R L
67 0043 Occurred @ day (val1) + month (val2) R J
68 0044 Occurred @ hour (val1) + min (val2) R J
69 0045 Humidity average Hi Word – Sensor 2 R L
70 0046 Humidity average Lo Word – Sensor 2 R L
71 0047 Not Used
72 0048 Not Used
73 0049 Temp max – Sensor 1 R H
74 004A Occurred @ day (val1) + month (val2) R J
75 004B Occurred @ hour (val1) + min (val2) R J
76 004C Temp min – Sensor 1 R H
77 004D Occurred @ day (val1) + month (val2) R J
78 004E Occurred @ hour (val1) + min (val2) R J
79 004F Temp average – Sensor 1 R H
80 0050 Temp max – Sensor 2 R H
81 0051 Occurred @ day (val1) + month (val2) R J
82 0052 Occurred @ hour (val1) + min (val2) R J
83 0052 Temp min – Sensor 2 R H
Address
hex
Function
Read/
Write
Default
Value
Register
Confi g- uration
Michell Instruments 55
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APPENDIX E
Liquidew EExd User’s Manual
Address
dec
84 0053 Occurred @ day (val1) + month (val2) R J
85 0054 Occurred @ hour (val1) + min (val2) R J
86 0055 Temp average – Sensor 2 R H
87 0056 Not Used
88 0057 Not Used
89 0058 Set-up access code - 7316 W I
90 005A Diagnostics/Set-up Command Register W G
91 005B* CALZ WDP 0 calibration value – Sensor 2 R F
92 005C* CALS WDP 2nF calibration value – Sensor 2 R F
93 005D* CALT WDP thermistor cal value – Sensor 2 R F
94 005E* Not used
95 005F* Not used
96 0060* Not used
97 0061* mA1 calibration value high in % (100%=23 mA) R/W A
98 0062* mA1 calibration value low in % (100%=23 mA) R/W A
99 0063* mA2 calibration value high in % (100%=23 mA) R/W A
100 0064* mA2 calibration value low in % (100%=23 mA) R/W A
101 0065 Force mA1 to a value in % of (100%=23 mA) W A
102 0066 Force mA2 to a value in % of (100%=23 mA) W A
103 0067* CALZ WDP 0 calibration value – Sensor 1 R F
104 0068* CALS WDP 2nF calibration value – Sensor 1 R F
105 0069* CALT WDP thermistor cal value – Sensor 1 R F
106 006A* WDP Pressure cal LO value – Sensor 2 R F
107 006B* WDP Pressure cal HI value – Sensor 2 R F
108 006C* WDP Pressure cal LO value – Sensor 1 R F
109 006D* WDP Pressure cal HI value – Sensor 1 R F
110 006E* mA3 calibration value high in % (100%=23 mA) R/W A
111 006F* mA3 calibration value low in % (100%=23 mA) R/W A
112 0070* mA4 calibration value high in % (100%=23 mA) R/W A
113 0071 mA4 calibration value low in % (100%=23 mA) R/W A
114 0072 Force mA3 to a value in % of (100%=23 mA) W A
115 0073* Force mA4 to a value in % of (100%=23 mA) W A
116 0074* Not used
117 0075 Not Used
118 0076* Sensor 2 pressure f.s.d. R/W F
119 0077* Sensor 1 pressure f.s.d. R/W F
120 0078 Internal Thermistor Calibration Value R/W A
121 0079 Supply Voltage as % of 12V (1.00 = 12V) R A
Address
hex
Function
Read/
Write
Default
Value
Register
Confi g- uration
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Sensor 1 Calibration Correction
Address
dec
186 Sn1 20°Cdp Ref R/W H
187 Sn1 10°Cdp Ref R/W H
188 Sn1 0°Cdp Ref R/W H
189 Sn1 -10°Cdp Ref R/W H
190 Sn1 -20°Cdp Ref R/W H
191 Sn1 -30°Cdp Ref R/W H
192 Sn1 -40°Cdp Ref R/W H
193 Sn1 -50°Cdp Ref R/W H
194 Sn1 -60°Cdp Ref R/W H
195 Sn1 -70°Cdp Ref R/W H
196 Sn1 -80°Cdp Ref R/W H
197 Sn1 -90°Cdp Ref R/W H
198 Sn1 -100°Cdp Ref R/W H
199 Sn1 20°Cdp Cal R/W H
200 Sn1 10°Cdp Cal R/W H
201 Sn1 0°Cdp Cal R/W H
202 Sn1 -10°Cdp Cal R/W H
203 Sn1 -20°Cdp Cal R/W H
204 Sn1 -30°Cdp Cal R/W H
205 Sn1 -40°Cdp Cal R/W H
206 Sn1 -50°Cdp Cal R/W H
207 Sn1 -60°Cdp Cal R/W H
208 Sn1 -70°Cdp Cal R/W H
209 Sn1 -80°Cdp Cal R/W H
210 Sn1 -90°Cdp Cal R/W H
211 Sn1 -100°Cdp Cal R/W H
Address
hex
Function
Read/
Write
APPENDIX E
Default
Value
Register
Confi g- uration
Michell Instruments 57
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APPENDIX E
Address
dec
213 Sn2 10°Cdp Ref R/W H
214 Sn2 0°Cdp Ref R/W H
215 Sn2 -10°Cdp Ref R/W H
216 Sn2 -20°Cdp Ref R/W H
217 Sn2 -30°Cdp Ref R/W H
218 Sn2 -40°Cdp Ref R/W H
219 Sn2 -50°Cdp Ref R/W H
220 Sn2 -60°Cdp Ref R/W H
221 Sn2 -70°Cdp Ref R/W H
222 Sn2 -80°Cdp Ref R/W H
223 Sn2 -90°Cdp Ref R/W H
224 Sn2 -100°Cdp Ref R/W H
225 Sn2 20°Cdp Cal R/W H
226 Sn2 10°Cdp Cal R/W H
227 Sn2 0°Cdp Cal R/W H
228 Sn2 -10°Cdp Cal R/W H
229 Sn2 -20°Cdp Cal R/W H
230 Sn2 -30°Cdp Cal R/W H
231 Sn2 -40°Cdp Cal R/W H
232 Sn2 -50°Cdp Cal R/W H
233 Sn2 -60°Cdp Cal R/W H
234 Sn2 -70°Cdp Cal R/W H
235 Sn2 -80°Cdp Cal R/W H
236 Sn2 -90°Cdp Cal R/W H
237 Sn2 -100°Cdp Cal R/W H
Address
hex
Function
Liquidew EExd User’s Manual
Sensor 2 Calibration Correction
Read/
Write
Default
Value
Register
Confi g- uration
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Liquidew EExd User’s Manual
Address
dec
257 0101 Time Hours + Mins @ t 0 R J
258 0102 Humidity 1 Hi Word @ t 0 R L
259 0103 Humidity 1 Lo Word Pressure @ t 0 R L
260 0104 Temperature 1 @ t 0 R H
261 0105 Humidity 2 Hi Word @ t 0 R L
262 0106 Humidity 2 Lo Word Pressure @ t 0 R L
263 0107 Temperature 2 @ t 0 R H
264 0108 Date Day + Month @ t 1 R J
265 0109 Time Hours + Mins @ t 1 R J
266 010A Humidity 1 Hi Word @ t 1 R L
267 010B Humidity 1 Lo Word Pressure @ t 1 R L
268 010C Temperature 1 @ t 1 R H
269 010D Humidity 2 Hi Word @ t 1 R L
270 010E Humidity 2 Lo Word Pressure @ t 1 R L
271 010F Temperature 2 @ t 1 R H
Address
hex
Function
Data Logging
Read/
Write
APPENDIX E
Default
Value
Register
Confi g- uration
1449 05A9 Date Day + Month @ 149 R J
1450 05AA Time Hours + Mins @ t 149 R J
1451 05AB Humidity 1 Hi Word @ t 149 R L
1452 05AC Humidity 1 Lo Word Pressure @ t 149 R L
1453 05AD Temperature 1 @ t 149 R H
1454 05AE Humidity 2 Hi Word @ t 149 R L
1455 05AF Humidity 2 Lo Word Pressure @ t 149 R L
1456 05B0 Temperature 2 @ t 149 R H
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APPENDIX E
Address
dec
1461 05B5 User Cs Table 1, Cs Value at 10°C R/W F
1462 05B6 User Cs Table 1, Cs Value at 20°C R/W F
1463 05B7 User Cs Table 1, Cs Value at 30°C R/W F
1464 05B8 User Cs Table 1, Cs Value at 40°C R/W F
1465 05B9 User Cs Table 1, Cs Value at 50°C R/W F
1466 05BA User Cs Table 2, Cs Value at 0°C R/W F
1467 05BB User Cs Table 2, Cs Value at 10°C R/W F
1468 05BC User Cs Table 2, Cs Value at 20°C R/W F
1469 05BD User Cs Table 2, Cs Value at 30°C R/W F
1470 05BE User Cs Table 2, Cs Value at 40°C R/W F
1471 05BF User Cs Table 2, Cs Value at 50°C R/W F
1472 05C0 User Cs Table 3, Cs Value at 0°C R/W F
1473 05C1 User Cs Table 3, Cs Value at 10°C R/W F
1474 05C2 User Cs Table 3, Cs Value at 20°C R/W F
1475 05C3 User Cs Table 3, Cs Value at 30°C R/W F
1476 05C4 User Cs Table 3, Cs Value at 40°C R/W F
1477 05C5 User Cs Table 3, Cs Value at 50°C R/W F
1478 05C6 User Cs Table 4, Cs Value at 0°C R/W F
1479 05C7 User Cs Table 4, Cs Value at 10°C R/W F
1480 05C8 User Cs Table 4, Cs Value at 20°C R/W F
1481 05C9 User Cs Table 4, Cs Value at 30°C R/W F
1482 05CA User Cs Table 4, Cs Value at 40°C R/W F
1483 05CB User Cs Table 4, Cs Value at 50°C R/W F
1484 05CC User Solute 1 Label Char 1 R/W F
1485 05CD User Solute 1 Label Char 2 R/W F
1486 05CE User Solute 1 Label Char 3 R/W F
1487 05CF User Solute 1 Label Char 4 R/W F
1488 05D0 User Solute 1 Label Char 5 R/W F
1489 05D1 User Solute 1 Label Char 6 R/W F
1490 05D2 User Solute 1 Label Char 7 R/W F
1491 05D3 User Solute 1 Label Char 8 R/W F
1492 05D4 User Solute 2 Label Char 1 R/W F
1493 05D5 User Solute 2 Label Char 2 R/W F
1494 05D6 User Solute 2 Label Char 3 R/W F
1495 05D7 User Solute 2 Label Char 4 R/W F
1496 05D8 User Solute 2 Label Char 5 R/W F
1497 05D9 User Solute 2 Label Char 6 R/W F
1498 05DA User Solute 2 Label Char 7 R/W F
1499 05DB User Solute 2 Label Char 8 R/W F
1500 05DC User Solute 3 Label Char 1 R/W F
1501 05DD User Solute 3 Label Char 2 R/W F
1502 05DE User Solute 3 Label Char 3 R/W F
1503 05DF User Solute 3 Label Char 4 R/W F
1504 05E0 User Solute 3 Label Char 5 R/W F
Address
hex
Function
Liquidew EExd User’s Manual
User Cs tables
Read/
Write
Default
Value
Register
Confi g- uration
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APPENDIX E
Address
dec
1505 05E1 User Solute 3 Label Char 6 R/W F
1506 05E2 User Solute 3 Label Char 7 R/W F
1507 05E3 User Solute 3 Label Char 8 R/W F
1508 05E4 User Solute 4 Label Char 1 R/W F
1509 05E5 User Solute 4 Label Char 2 R/W F
1510 05E6 User Solute 4 Label Char 3 R/W F
1511 05E7 User Solute 4 Label Char 4 R/W F
1512 05E8 User Solute 4 Label Char 5 R/W F
1513 05E9 User Solute 4 Label Char 6 R/W F
1514 05EA User Solute 4 Label Char 7 R/W F
1515 05EB User Solute 4 Label Char 8 R/W F
Address
hex
Function
Read/
Write
Default
Value
Register
Confi g- uration
NOTE: To download logged data, calculate the start address by the following formula: (sample number x 8) + 256. Start addresses that do not coincide with the fi rst register of a sample will generate an exception response. Due to the maximum limit of 125 data registers that can be read in one transmission, as defi ned by the Modbus RTU standard, only 20 samples can be downloaded at any one time. Therefore, eight reads are required to download all 150 samples.
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APPENDIX F
Liquidew EExd User’s Manual
Appendix F
Modbus RTU Details
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Appendix F Modbus RTU Details
F.1 Message Framing
APPENDIX F
START ADDRESS
3.5t 1 byte 1 byte n x bytes 2 bytes 3.5t
FUNCTION
CODE
DATA CRC END
Start and End
The message begins and ends with a silent delay of 3.5 character times at the baud rate of the network.
Address
The fi rst byte transmitted is the address of the instrument, which has a range of 1 to 247 or 01H to F7H. The master addresses an instrument by placing the address in the address byte and, if matched, a Liquidew EExd will response to the message, otherwise it will be ignored. See Appendix E on setting the address.
Function Code
The function code tells the Liquidew EExd which operation is to be performed on the data in the following data bytes. The only valid codes are
06 (Write To Single Register) as these are the only two implemented.
or
An exception can occur if the message contains an unsupported function code, an illegal data address or an illegal data value. If this occurs, the function code is incremented by 80H and the data bytes returned are set to a value that describes the error. See Appendix F.2.
03 (Read Holding Registers)
Data Bytes
The data bytes within the message from the master contain additional information that the Liquidew EExd must use to perform the action defi ned in the function code, such as the starting register address and the number of registers to be retrieved.
CRC
The CRC is a 2-byte error check value from the result of a Cyclical Redundancy Check calculation performed on the message contents. The CRC is appended to the message as the last fi eld in the message. The low-order byte is appended fi rst, followed by the high-order byte.
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APPENDIX F
A
A
F.2 Implemented Functions
03 Read Holding Registers
This function code is used to read the contents of a contiguous block of holding registers, where the master specifi es the starting address and the number of registers to be read.
Figure 33
that may be raised.
shows the state diagram of how the message is processed with the exceptions
ENTRY
Address in message = Instrument Address
ddress in message = Instrument
Liquidew EExd User’s Manual
Exception Code = 01
Exception Code = 03
Function code supported
0x0000 <= Quantity of Registers <=
0X007d
Exception Code = 02
Exception Code = 04
Starting Address = OK
ND
Starting Address + Number of Registers =
Request Processing
Reading Registers = OK
OK
Sends Exception Response
Figure 32
Sends Response with data
EXIT
Reading Holding Registers State Diagram
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The table below is an example of a message sent by the master, to read the time to the next log (register 7) and Channel 2 sample temperature (register 8). The message shows a master addressing a Liquidew EExd with a slave address of 01H and a Modbus function of 03H that informs the Liquidew EExd that it wishes to read two registers starting from address 07H. Bytes 3 & 4 hold the starting address and bytes 5 & 6 hold the number of registers to be read. Bytes 7 & 8 contain the CRC code that is calculated using bytes 1 to 6 as represented below.
Byte No Meaning Value
1 Slave Address 01H 2 Modbus function code 03H 3 Starting Address MSB 00H 4 Starting Address LSB 07H 5 No of points MSB 00H 6 No of points LSB 02H 7 CRC Lo Byte ??H 8 CRC Hi Byte ??H
APPENDIX F
Read Request Message
In response to the above message, the Liquidew EExd may transmit the following message:
Byte No Meaning Value
1 Slave Address 01H 2 Modbus function code 03H 3 Byte Count 04H 4 Data MSB 05H 5 Data LSB 26H 6 Data MSB 00H 7 Data LSB FAH 8 CRC Lo Byte ??H 9 CRC Hi Byte ??H
Read Response Message
This response repeats the address of the Liquidew EExd and the function code, along with the byte count, the data and the CRC. In this example, the request asked for the values from two registers. Therefore, the number of bytes returned is four. The value of register 7 is contained in bytes 4 & 5 and the value of register 8 in bytes 6 & 7. Register 7 = 5m 26s and register 7 = 00FA = 252 = 25.2°C in this example. Any errors within the data of Read Request Message will result in an exception being raised.
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APPENDIX F
06 Write to Single Register
This function code is used to write a 16 bit value into a single register. The master specifi es the address and the value to be written. how the message is processed with the exceptions that may be raised.
ENTRY
Exception Code = 01
Liquidew EExd User’s Manual
Address in message = Instrument Address
Function code supported
Figure 34
shows the state diagram of
Exception Code = 03
Exception Code = 02
0x0000 <= Reg i ster Value<= 0xFFFF
Register Address == OK
Request Processing
Write To Single Register = OK
Exception Code = 04
Mirrors Request
Sends Exception Response EXIT
Figure 33
Write Single Register State Diagram
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The table below shows the data bytes in a Write To Single Register message. Bytes 1 to 4 contain the address of the Liquidew EExd, Modbus function, starting register address and the data value to be written. In this example a master sends FC18H to address 0015H, to a Liquidew EExd with an address of 01H. The CRC is calculated using the data in bytes 1 to 6.
Byte No Meaning Value
1 Slave Address 01H 2 MODBUS function code 06H 3 Starting Address MSB 00H 4 Starting Address LSB 15H 5 Data MSB FCH 6 Data LSB 18H 7 CRC Lo Byte ??H 8 CRC Hi Byte ??H
Write Single Register Request and Response
APPENDIX F
The normal response from the Liquidew EExd is to re-transmit the received message. However, if the data within the message is incorrect then an exception response will be transmitted.
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APPENDIX F
F.3 Exceptions
A message request from the master will raise an exception response from the slave (Liquidew EExd) if:
i. the function code is unsupported
ii. the register quantity > 127 (0x007D)
iii. the register address is invalid
iv. the register address + the quantity of register is invalid
v. an error occurred while performing the function
The exception response will contain the function code incremented by 80H and the exception code.
The table below lists the codes supported, along with an explanation of each code.
Liquidew EExd User’s Manual
Code Name Meaning
01
02
03
04
Example of an Exception Response that reads a discrete inputs message generating an illegal function exception.
ILLEGAL FUNCTION
ILLEGAL DATA ADDRESS
ILLEGAL DATA VALUE
SLAVE DEVICE FAILURE
The function code received in the query is not an allowable action for the slave
The data address received in the query is not allowable. More specifi cally, the combination of starting address and number of registers is invalid for the slave
A value contained in the query data eld is not an allowable value for the slave
An unrecoverable error occurred while the slave was attempting to perform the requested action
Byte Meaning Value
1 Slave Address 01H 2 Function 82H 3 Exception Code 01H 4 CRC ??
The example above shows the function code (02H) sent in the request has been incremented by 80H with the exception code 01H included as the data within the message.
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APPENDIX I
Appendix G
Register Number Formats
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APPENDIX I
Appendix G Register Number Formats
Register Configuration A
1514131211109876543210 rrrrrrrrrrrrrrrr
Sign bit = 1 for –ve values (signed int) 7FFF = 327.67 8000 = -327.68
The value in bits (15 to 0) + 1 is divided by 100 to give 0.01 resolution for dew-point and temperature values.
Value
Register Configuration B – Sensor Humidity Setting
Liquidew EExd User’s Manual
1514131211109876543210 r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w
0x0000 = Dew point in degrees 0x0001 = Moisture in ppm
W
Register Configuration C – Error Register
1514131211109876543210 rrrrrrrrrrrrrrrr
Bit HEX Error Condition
0 0001 Channel 1 dew point under range <-120°C (<-184°F) 1 0002 Channel 1 dew point over range >+30°C (>+86°F) 2 0004 Channel 1 temperature out of range >+50 or <0°C (>+122 or <32°F) 3 0008 Channel 1 low fl ow (<0.1 l/min) 4 0010 Channel 1 high fl ow (>0.9 l/min) 5 0020 Channel 1 moisture saturation condition (dew point temperature) 6 0040 Channel 1 calibration table error (checks sensor impedance values are
increasing in the correct direction) 7 0080 Channel 2 dew point under range <-120°C (<-184°F) 8 0100 Channel 2 dew point over range >+30°C (>+86°F) 9 0200 Channel 2 temperature out of range >+50 or <0°C (>+122 or <32°F)
10 0400 Channel 2 low fl ow (<0.1 l/min) 11 0800 Channel 2 high fl ow (>0.9 l/min) 12 1000 Channel 2 moisture saturation condition (dew point temperature) 13 2000 Channel 2 calibration table error (checks sensor impedance values are
increasing in the correct direction)
14 4000 Internal heater fault (internal temperature set-point not achievable)
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APPENDIX I
Register Configuration D
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
- Status Word
rrrrrrrrrr
N/A
N/A
Heater
(Alarm 1)
Flow Channel
Alarm Channel 2
Alarm Channel 1
Flow Channel
Sensor 1 Fitted
Sensor 2 Fitted
1 = ON or Fitted or ERROR 0 = OFF or Not Fitted or NO ERROR
Register Configuration E - Units Command
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
w w w r/w r/w r/w r/w
N/A
Reset
Reset
°C / °F
0 = °C 1 = Initiate
Register Configuration F
1514131211109876543210 r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w
Unsigned integer Range = 0 to 65535 Unsigned Integer /100 for fl ow value in l/min
Register Configuration H
1514131211109876543210 rrrrrrrrrrrrrrrr
Sign bit = 1 for –ve values (signed int) 7FFF = 3276.7 8000 = -3276.8
The value in bits (15 to 0) + 1 is divided by 10 to give 0.1 resolution for dew-point and temperature values.
Value
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APPENDIX I
Register Configuration I
1514131211109876543210 r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w
Val 1 & 2 are in BCD, therefore 10H = 10, 58H = 58 and 09H = 9 etc. As a result A to F are not valid values.
Values for Cycle Time and Max Cool Time are in units of 5 mins.
Register Configuration J
1514131211109876543210 r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w
Val 1
Day or Hours
Liquidew EExd User’s Manual
Val 2
Minutes or Month
Values in HEX i.e. 17th March = 1103H
Register Configuration K – signed int
1514131211109876543210 rrrrrrrrrrrrrrrr
Value
Sign bit = 1 for –ve values (signed int) 7FFF = 32767 8000 = -32768
Register Configuration L - Floating Point Representation
The humidity values for sensors 1 & 2 are represented in IEEE-754 single precision oating point format, in order to cater for the wide range in the value of ppmV. This format is ‘Big Ended’ which means that the High byte is at a lower address in memory than the Lo byte, and is represented as such in the register memory map. The IEEE-754 format is shown below.
Bit 31
Sign bit
0 = +
1 = -
Bits 30 to 23
Exponent Field
Has a +127 bias value
Bits 22 to 0
mantissa
Decimal representation of binary
Where 1.0  value < 2.0
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Examples of fl oating point to HEX are shown below.
1) +10.3
sign bit = 0
Exponent = 3, therefore exponent fi eld = 127 + 3 = 130, and bits 30 to 23 = 1000 0010 Mantissa = 1.2875 which in binary representation = 1010 0100 1100 1100 1100 1101
Adjusting the mantissa for the exponent moves the decimal point to the right if positive and to the left if negative.
As the exponent is = 3 then the mantissa becomes = 1010 0100 1100 1100 1100 1101, therefore:-
1010 = (1x23) + (0x22) + (1x21 ) + (0x20) = 10 and
0100 1100 1100 1100 1101 = (0x2
Therefore the word value = 0100 0001 0010 0100 1100 1100 1100 1101 = 4124CCCD
-1
) + (1x2-2) + -- + (1x2
-20
) = 0.3
APPENDIX I
Consequently, for sensor 1 register 0001 = 4124 and register 0002 = CCCD
2) - 0.0000045
sign bit = l
Exponent = -18, therefore exponent fi eld = 127 + (-18) = 109, & bits 30 to 23 = 0110 1101 Mantissa = 1.179648 which in binary representation = 1001 0110 1111 1110 1011 0101
i.e. (1x2
-18
) + (1x2
-21
) + (1x2
-23
) etc = 0.0000045
Therefore the word value = 1011 0110 1001 0110 1111 1110 1011 0101 = B696FEB5
Consequently, for sensor 1 register 0001 = B696 and register 0002 = FEB5
Register Configuration M
1514131211109876543210 r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w
Unsigned integer / 10 Range = 0 to 6553.5
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APPENDIX H
Liquidew EExd User’s Manual
Appendix H
Hazardous Area
Certifi cation
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!
Appendix H Hazardous Area Certifi cation
The Liquidew EExd is certifi ed compliant to the ATEX Directive (2014/34/EU) and IECEx for use within Zone 1 and Zone 2 Hazardous Areas and has been assessed so by Element Materials Technology Ltd (Notifi ed Body 0891).
The Liquidew EExd is certifi ed compliant to North American Standards (USA and Canada) for use within Class I, Division 1, Groups B, C and D Hazardous Locations and has been assessed so by CSA.
H.1 Product Standards
This product conforms to the Standards:
EN60079-0:2012/ A11:2013 IEC60079-0:2011 EN60079-1:2007 IEC60079-1:2007 C22.2 No. 142-M1987 UL508 C22.2 No. 30-M1986 UL1203
APPENDIX H
H.2 Product Certifi cation
This product is attributed with the product certifi cation code:
ATEX & IECEx II 2G Ex d IIB + H2 T5 Gb (-40°C to +44°C) T4 Gb (-40°C to +60°C) North American Class I, Division 1, Groups B, C & D T5, Tamb -40°C to +44°C T4, Tamb -40°C to +60°C
H.3 Global Certifi cates/Approvals
ATEX TRAC11ATEX21322X IECEx TRC 11.0012X cCSAus 1701657 TC TR Ex RU C-GB. 05.B.00152
These certifi cates can be viewed or downloaded from our website at: http://www.michell.com
Special attention should be paid to the
for Safe Use
and the
certifi cates shown on our website.
Conditions of Certifi cation
Special Conditions
listed in the
Michell Instruments 75
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APPENDIX H
H.4 Special Conditions of Use
1. Do not open when an explosive gas atmosphere may be present.
2. External cables shall be compatible with a temperature of 93°C (T5) or 109°C (T4).
3. Maximum process pressure shall not exceed 50 barg. Maximum permissible process pressure is marked on the equipment.
4. Maximum permitted sample fl ow rate into the enclosure shall not exceed
0.3LPH.
5. All process lines shall be purged to ensure the process gas or liquid is above its upper explosive limit before applying power.
6. Where painted or powder coated, the enclosures could present an electrostatic hazard. Clean only with a damp or anti-static cloth.
7. The enclosure is to be earthed externally using the earth point provided.
8. Only suitably ATEX / IECEx certifi ed (as appropriate) cable glands and blanking elements shall be used.
Liquidew EExd User’s Manual
Refer to the relevant sections within this manual for the connection, wiring and cable glanding requirements.
H.5 Maintenance and Installation
The Liquidew EExd must only be installed by suitably qualifi ed personnel and in accordance with the instructions provided and the terms of the applicable product certifi cates.
Maintenance and servicing of the product must only be carried out by suitably trained personnel or returned to an approved Michell Instruments’ Service Center.
Flame paths are not intended to be repaired.
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Liquidew EExd User’s Manual
APPENDIX I
Appendix I
Quality, Recycling
& Warranty
Information
Michell Instruments 77
Page 86
APPENDIX I
Liquidew EExd User’s Manual
Appendix I 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/uk/compliance
This page contains information on the following directives:
• ATEX Directive
• Calibration Facilities
• Confl ict Minerals
• FCC Statement
• Manufacturing Quality
Modern Slavery Statement
Pressure Equipment Directive
• REACH
• RoHS2
• WEEE2
• Recycling Policy
Warranty and Returns
This information is also available in pdf format.
78 97097 Issue 13.1, July 2018
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Liquidew EExd User’s Manual
APPENDIX J
Appendix J
Return Document &
Decontamination Declaration
Michell Instruments 79
Page 88
APPENDIX J
Liquidew EExd User’s Manual
Appendix J Return Document & Decontamination Declaration
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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
PDWHULDOV)RUPRVWDSSOLFDWLRQVLQYROYLQJVROYHQWVDFLGLFEDVLFÀDPPDEOHRUWR[LFJDVHVD VLPSOHSXUJHZLWKGU\ JDVGHZSRLQW&RYHUKRXUVVKRXOGEHVXI¿FLHQWWRGHFRQWDPLQDWHWKHXQLWSULRUWRUHWXUQ
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
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http://www.michell.com
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