Michell Instruments LQD-MON/SYS Manual

Download

Page 1

Liquidew EExd

Process Moisture Analyzer

User’s Manual

97097 Issue 13.1

July 2018

Page 2

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

Code

Serial Number

Invoice Date

Location of Instrument

Tag No

Analyzer

Code

Serial Number

Invoice Date

Location of Instrument

Tag No

Analyzer

Code

Serial Number

Invoice Date

Location of Instrument

Tag No

Page 3

Liquidew EExd

For Michell Instruments' contact information please go to

www.michell.com

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.

Page 4

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

iv 97097 Issue 13.1, July 2018

Page 5

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

Michell Instruments v

Page 6

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

vi 97097 Issue 13.1, July 2018

Page 7

Liquidew EExd User’s Manual

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.

Michell Instruments vii

Page 8

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)

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.

viii 97097 Issue 13.1, July 2018

Page 9

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

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 ﬂ 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 ﬁ 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.

Michell Instruments 1

Page 10

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

)

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

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:

Hexane, Propane, Isopropylbenzene, Benzene, Butane, Isobutane, Propylene, Cyclohexane, 1-Butene and Octene. See Appendix B for instrument display names.

2 97097 Issue 13.1, July 2018

Page 11

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

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.

Michell Instruments 3

Page 12

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

4 97097 Issue 13.1, July 2018

Page 13

Liquidew EExd User’s Manual

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

Michell Instruments 5

Page 14

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

6 97097 Issue 13.1, July 2018

Page 15

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

Michell Instruments 7

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.

8 97097 Issue 13.1, July 2018

Page 17

Liquidew EExd User’s Manual

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:

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 ﬁ 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.

Michell Instruments 9

Page 18

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

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

10 97097 Issue 13.1, July 2018

Page 19

Liquidew EExd User’s Manual

2.5.1 Pipework

INSTALLATION

MICHELL MOISTURE

SENSOR

FLAME

ARRESTOR

SAMPLE IN SAMPLE OUT SAMPLE IN SAMPLE OUT

SAMPLING BLOCK

FLOW METER

CHANNEL 1

FLAME

ARRESTOR

MICHELL MOISTURE

FLAME ARRESTOR BREATHER

ARRESTOR

FLAME

{

SENSOR

FLOW METER

SAMPLING BLOCK

ARRESTOR

CHANNEL 2

OPTIONAL

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)

Michell Instruments 11

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

Page 21

Liquidew EExd User’s Manual

AL3AL2AL1 AL4 COMMS Channel 1 Channel 2

PL16

NC C NO NC C NO

7891011

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

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

Page 23

Liquidew EExd User’s Manual

MINIMUM REQUIREMENTS FOR START UP PURGING

INSTALLATION

INLET

NEEDLE VALVE

SAMPLE

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.

CHANNEL 1

SAMPLE IN SAMPLE OUT

LIQUIDEW EExd

SAMPLE IN SAMPLE OUT

CHANNEL 2

Minimum Requirements for Start-up Purging

FLOW CONTROL

NEEDLE VALVE

FLOW CONTROL

NEEDLE VALVE

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

Cdp

TEMPERATURE

Cdp

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

Up/Down

Arrow

Buttons

Cdp

SELECT

Button

Figure 9

MENU MAIN

MENU/

MAIN

Button

User Interface

VFD Display

Blue LEDs

16 97097 Issue 13.1, July 2018

Page 25

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

MAIN

‘MENU/MAIN’ Button

Michell Instruments 17

Page 26

OPERATION

3.3 Menu Structure

Liquidew EExd User’s Manual

Figure 14

Status Page

below shows a map of the menu structure.

KEY

Main Menu

SELECT

Error ?

YES

Error Report

Page

SELECT

Choices

Menu Pages

Other Pages

STATUS

View

Logged

Data

SELECT

LOGGING

View

Statistics

SELECT

Page

SELECT

System

Error Codes

View

Faults

SELECT

Logged

Start-Up

Banner

Main Page

MENU MAIN

VIEW/ADJ

VARIABLES

SELECT

Password

Page

SELECT

Password

Correct?

YES

SENSOR

INFO

Press MENU/MAIN button to

get back to Main Page from

CONTACT

INFO

SELECT

Sensor 1 Sensor 2

SELECT

Sensor 1

Info

SELECT

Sensor 2

Info

OPTIONAL

MENU MAIN

any location

MAIN

Contact/About

Page

Logged Pages

Page

Variables Pages

Use Up/Down arrow buttons to scroll through menu items and pages

Figure 13

Menu Structure

18 97097 Issue 13.1, July 2018

Page 27

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

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

Press the MAIN/MENU button to return to the MAIN Page.

20 97097 Issue 13.1, July 2018

Page 29

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

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

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

SELECT

Up () and

Variables Page in single channel conﬁ guration with Dew Point selected

22 97097 Issue 13.1, July 2018

Page 31

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)

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

24 97097 Issue 13.1, July 2018

Page 33

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

ﬁ 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

26 97097 Issue 13.1, July 2018

Page 35

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)

28 97097 Issue 13.1, July 2018

Page 37

Liquidew EExd User’s Manual



MAINTENANCE



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

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.

Liquidew EExd User’s Manual

Observe de-energize durations

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

Page 39

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

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

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

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)

Michell Instruments 31

Page 40

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.

32 97097 Issue 13.1, July 2018

Page 41

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 ﬂ 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

Page 42

APPENDIX A

Liquidew EExd User’s Manual

Appendix A

Technical Speciﬁ cations

34 97097 Issue 13.1, July 2018

Page 43

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

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)

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

Page 44

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)

36 97097 Issue 13.1, July 2018

Page 45

Liquidew EExd User’s Manual

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

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

Page 46

APPENDIX A

A.2 Pipework Connections

Liquidew EExd User’s Manual

SENSOR

MICHELL MOISTURE

SAMPLING BLOCK

FLOW

METER

FLAME

ARRESTOR

{

OPTIONAL

CHANNEL 2

FLAME

BREATHER

ARRESTOR

FLAME

ARRESTOR

SAMPLING BLOCK

FLOW

METER

SENSOR

FLAME

MICHELL MOISTURE

ARRESTOR

{

CHANNEL 1

SAMPLE IN SAMPLE OUT SAMPLE IN SAMPLE OUT

Figure 29

38 97097 Issue 13.1, July 2018

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

B A GND

PL20 PL15 PL14 PL19

13 14 15

16 17 18 19 20 21 22 23

LEN

mA2-

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

Page 48

APPENDIX B

Liquidew EExd User’s Manual

Appendix B

Variable Deﬁ nitions

40 97097 Issue 13.1, July 2018

Page 49

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

Michell Instruments 41

Page 50

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

42 97097 Issue 13.1, July 2018

Page 51

Liquidew EExd User’s Manual

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 ﬁ 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.

Michell Instruments 43

Page 52

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)

U1 U2 U3 and U4

44 97097 Issue 13.1, July 2018

Page 53

Liquidew EExd User’s Manual

APPENDIX C

Appendix C

Software

Michell Instruments 45

Page 54

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

46 97097 Issue 13.1, July 2018

Page 55

Liquidew EExd User’s Manual

APPENDIX D

Appendix D

Calibration Correction

Michell Instruments 47

Page 56

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

From time to time the Liquidew EExd may be calibrated by an external calibration agency, and similar data will be provided.

48 97097 Issue 13.1, July 2018

Page 57

Liquidew EExd User’s Manual

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

50 97097 Issue 13.1, July 2018

Page 59

Liquidew EExd User’s Manual

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

Michell Instruments 51

Page 60

APPENDIX E

Liquidew EExd User’s Manual

Appendix E

Modbus RTU

Communications

52 97097 Issue 13.1, July 2018

Page 61

Liquidew EExd User’s Manual

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 ﬁ 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

Page 62

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

Conﬁ g- uration

54 97097 Issue 13.1, July 2018

Page 63

Liquidew EExd User’s Manual

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

Conﬁ g- uration

Michell Instruments 55

Page 64

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

Conﬁ g- uration

56 97097 Issue 13.1, July 2018

Page 65

Liquidew EExd User’s Manual

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

Conﬁ g- uration

Michell Instruments 57

Page 66

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

Conﬁ g- uration

58 97097 Issue 13.1, July 2018

Page 67

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

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

Michell Instruments 59

Page 68

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

Conﬁ g- uration

60 97097 Issue 13.1, July 2018

Page 69

Liquidew EExd User’s Manual

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

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.

Michell Instruments 61

Page 70

APPENDIX F

Liquidew EExd User’s Manual

Appendix F

Modbus RTU Details

62 97097 Issue 13.1, July 2018

Page 71

Liquidew EExd User’s Manual

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.

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.

Michell Instruments 63

Page 72

APPENDIX F

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

Starting Address + Number of Registers =

Request Processing

Reading Registers = OK

Sends Exception Response

Figure 32

Sends Response with data

EXIT

Reading Holding Registers State Diagram

64 97097 Issue 13.1, July 2018

Page 73

Liquidew EExd User’s Manual

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.

Michell Instruments 65

Page 74

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

Request Processing

Write To Single Register = OK

Exception Code = 04

Mirrors Request

Sends Exception Response EXIT

Figure 33

Write Single Register State Diagram

66 97097 Issue 13.1, July 2018

Page 75

Liquidew EExd User’s Manual

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.

Michell Instruments 67

Page 76

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

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 ﬁ 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.

68 97097 Issue 13.1, July 2018

Page 77

Liquidew EExd User’s Manual

APPENDIX I

Appendix G

Michell Instruments 69

Page 78

APPENDIX I

Appendix G Register Number Formats

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

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

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)

70 97097 Issue 13.1, July 2018

Page 79

Liquidew EExd User’s Manual

APPENDIX I

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

- Status Word

rrrrrrrrrr

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

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

°C / °F

0 = °C 1 = Initiate

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

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



Michell Instruments 71

Page 80

APPENDIX 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.

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

1514131211109876543210 rrrrrrrrrrrrrrrr



Value

Sign bit = 1 for –ve values (signed int) 7FFF = 32767 8000 = -32768



The humidity values for sensors 1 & 2 are represented in IEEE-754 single precision ﬂ 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

72 97097 Issue 13.1, July 2018

Page 81

Liquidew EExd User’s Manual

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

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

Michell Instruments 73

Page 82

APPENDIX H

Liquidew EExd User’s Manual

Appendix H

Hazardous Area

Certiﬁ cation

74 97097 Issue 13.1, July 2018

Page 83

Liquidew EExd User’s Manual

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

Page 84

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.

76 97097 Issue 13.1, July 2018

Page 85

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

Page 87

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

'HFRQWDPLQDWLRQ&HUWL¿FDWH

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

80 97097 Issue 13.1, July 2018

Page 89

Page 90

http://www.michell.com