Kahn Optidew Series User manual

Optidew
Chilled Mirror Hygrometer
User's Manual
Kahn Instruments, Inc. October 2019
This document is the property of Kahn Instruments and may not, either in part or whole, be copied or
otherwise reproduced, communicated in any way to third parties nor stored in any data processing
system, without the written authority of Kahn Instruments, Inc.

Optidew
For Kahn Instruments' contact information please go to
www.kahn.com

Optidew User’s Manual
Kahn Instruments iii
1 INTRODUCTION ................................................................................................1
1.1 Optidew Series................................................................................................... 1
1.2 Optidew Sensor.................................................................................................. 2
2 INSTALLATION ..................................................................................................3
2.1 Mounting ........................................................................................................... 3
2.2 Instrument Connections...................................................................................... 5
2.2.1 Optidew Wall Mount ...................................................................................... 5
2.2.2 Optidew Bench Top ....................................................................................... 7
2.3 Electrical Connections ......................................................................................... 9
2.3.1 Electrical Supply............................................................................................ 9
2.3.2 Analog and Digital Communications.............................................................. 10
2.3.2.1 Digital Communications ......................................................................... 10
2.3.2.2 Current Outputs.................................................................................... 11
2.3.2.3 Relay Contacts...................................................................................... 11
2.4 Sensor Installation............................................................................................ 13
2.4.1 Environmental monitoring............................................................................ 13
2.4.2 Sample flow monitoring............................................................................... 13
2.4.3 Integral Sensor mounting ............................................................................ 14
2.5 Temperature Probe Installation.......................................................................... 14
2.6 Pressure Transmitter Installation........................................................................ 14
3 USER INTERFACE ............................................................................................15
3.1 Main Display .................................................................................................... 15
3.1.1 Main Screen................................................................................................ 16
3.1.2 Customizable Readouts................................................................................ 17
3.1.2.1 Locking the Analyzer ................................................................................... 17
3.1.3 Menu Structure........................................................................................... 18
3.1.4 Operational Status Display ........................................................................... 19
3.1.5 Sensor Status Display.................................................................................. 20
3.2 Setup Menus.................................................................................................... 21
3.3 Transmitter Version........................................................................................... 29
Contents
Safety ...............................................................................................................................vii
Warnings ........................................................................................................................vii
Electrical Safety..................................................................................................................vii
Pressure Safety ..................................................................................................................vii
Calibration (Factory Validation)........................................................................................... viii
Repair and Maintenance .................................................................................................... viii
Abbreviations......................................................................................................................ix

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3.3.1 Optics Calibration ............................................................................................. 29
4 OPERATION ....................................................................................................30
4.1 Operating Cycle................................................................................................ 30
4.2 Operating Guide ............................................................................................... 31
4.2.1 Description ................................................................................................. 31
4.2.2 Operating Practice....................................................................................... 31
4.3 Good Measurement Practice.............................................................................. 32
4.3.1 Sampling Hints............................................................................................ 32
4.3.2 First Time Operation.................................................................................... 35
4.4 Operational Functions ....................................................................................... 35
4.4.1 DCC Function.............................................................................................. 35
4.4.2 MAXCOOL Function ..................................................................................... 36
4.4.3 Frost Assurance Technology (FAST) .............................................................. 36
4.4.4 STANDBY Mode........................................................................................... 36
4.4.5 Parameter Conversions & Pressure Compensation ......................................... 37
4.4.6 Data Logging.............................................................................................. 37
4.5 Minimum Measurable Dew Points....................................................................... 37
4.6 Warnings and Faults ......................................................................................... 38
5 MAINTENANCE................................................................................................42
5.1 Mirror Cleaning................................................................................................. 42
5.2 Exchanging Sensors.......................................................................................... 43

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Figures
Figure 1 Optidew Wall Mount (wall mount) and Optidew Bench Top (bench top) ..........1
Figure 2 Optidew Wall Mount wall mounting points ....................................................3
Figure 3 Optidew Wall Mount display front panel .......................................................5
Figure 4 Optidew Wall Mount non-display front panel.................................................6
Figure 5 Optidew Wall Mount bottom panel ...............................................................6
Figure 6 Optidew Bench Top top panel......................................................................7
Figure 7 Optidew Bench Top left side panel ...............................................................7
Figure 8 Optidew Bench Top right side panel .............................................................8
Figure 9 Optidew Bench Top rear panel.....................................................................8
Figure 10 RS485 & analog output connector .............................................................10
Figure 11 Analog output connector...........................................................................11
Figure 12 Relay contact connector............................................................................11
Figure 13 Main screen .............................................................................................15
Figure 14 Main screen layout ...................................................................................16
Figure 15 DCC menu ...............................................................................................21
Figure 16 Logging screen.........................................................................................22
Figure 17 Outputs screen.........................................................................................23
Figure 18 Alarm screen............................................................................................24
Figure 19 Display screen..........................................................................................25
Figure 20 Clock screen ............................................................................................26
Figure 21 Inputs screen...........................................................................................27
Figure 22 Comms screen .........................................................................................28
Figure 23 Network settings screen............................................................................28
Figure 24 Typical operating cycle..............................................................................30
Figure 25 Room measurement example ....................................................................32
Figure 26 Mirror contamination warning symbol ........................................................33
Figure 27 Material permeability comparison...............................................................34
Figure 28 Formation of condensation........................................................................35
Figure 29 2-Stage minimum measurable dewpoint.....................................................40
Figure 30 System alarm...........................................................................................41
Figure 31 Mirror contamination warning....................................................................42
Figure 32 Sensor cleaning........................................................................................43

Optidew User’s Manual
vi October 2019
Appendices
Appendix A Technical Specifications..............................................................................44
Appendix B Modbus Register Map ................................................................................47
Appendix C Dimensional Drawings................................................................................56

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Kahn Instruments vii
Safety
The instrument is designed to be completely safe when installed and operated correctly in
accordance with the information provided in this manual.
This manual contains all the required information to install, operate and maintain this product.
Prior to installation and use of this product, this entire manual should be read and understood.
Installation and operation of this product should be carried out by suitably competent personnel
only. The installation and operation of this product must be in accordance with the instructions
provided and according to the terms of any associated safety certificates. Incorrect installation
and use of this product other than those described in this manual and other than its intended
purpose will render all warranties void.
Electricity and pressurized gas can be dangerous. This product must be installed and operated
only by suitable trained personnel.
No user serviceable parts inside
!
Warnings
!
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.
DANGER
Electric
Shock Risk
Where this symbol appears in the following sections it is used to
indicate areas of potential risk of electric shock.
Electrical Safety
Insure electrical safety is complied with by following the directions provided here and observing all
local operation & installation requirements at the intended location of use.
This product is completely safe when using any options and accessories supplied by the manufacturer
of this product for use with it. Refer to Section 2 (Installation) of this manual for further details.
Pressure Safety
For this product to operate satisfactorily, pressurized gas must be connected to it. Observe all the
information contained within this manual and all local operation & installation requirements at the
intended location of use. Refer to Section 2 (Installation) of this manual for further details.

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viii October 2019
Calibration (Factory Validation)
Prior to shipment, the instrument undergoes stringent factory calibration that is traceable to national
standards. Due to the inherent stability of the instrument, regular factory calibration is not required,
however recalibration is recommended to maintain measurement traceability.
Kahn Instruments can provide a fully traceable factory calibration service for the instrument and it is
recommended that this is considered at intervals of every year of the analyzer's life. Please contact
Kahn Instruments for further details (www.kahn.com).
Repair and Maintenance
Apart from user-replaceable components required for routine operational maintenance described
above, the instrument must only be maintained either by the manufacturer or an accredited service
agent.

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Kahn Instruments ix
Abbreviations
The following abbreviations are used in this manual:
A ampere
AC alternating current
atm pressure unit (atmosphere)
bara pressure unit (=100 kP or 0.987 atm) (absolute)
barg pressure unit (=100 kP or 0.987 atm) gauge
°C degrees Celsius
°F degrees Fahrenheit
EU European Union
hr hour
Hz Hertz
IEC International Electrotechnical Commission
IP Internet protocol
ml/min milliliters per minute
mg/m3milligrams per cubic meter
lbs/MMscf pounds per million standard cubic feet
mA milliampere
mins minutes
mmHg millimeter of mercury
Pa pascal
ppmVparts per million (by volume)
ppmWparts per million (by weight)
psia pound(s) per square inch (absolute)
psig pound(s) per square inch (gauge)
RH relative humidity
RS485/232 standards defining the electrical characteristics of drivers & receivers
RTC real time clock
RTU Remote Terminal Unit
SD storage device card
UART universal asynchronous receiver/transmitter
USB Universal Serial Bus
V Volts
" Inch
Δ delta
% percentage
Ω ohms

Optidew User’s Manual
Kahn Instruments 1
INTRODUCTION
1 INTRODUCTION
The Optidew chilled mirror hygrometer is based on the proven, fundamental condensation
temperature dewpoint principle, giving unmatched long-term drift-free performance.
Kahn offers three highly durable sensor options, which are suitable for measuring in a
wide variety of different samples.
1.1 Optidew Series
The Optidew series is available in two different enclosures:
Figure 1 Optidew Wall Mount and Optidew Bench Top
The Optidew Wall Mount features a compact ABS enclosure with an aluminium base
plate and 4 external lugs for easy mounting to a panel or wall. It is available with a 5.7"
touch screen display, or as a blind "transmitter only" version.
A weatherproof version of the Optidew Wall Mount enclosure is available with a modified
connector panel to improve ingress protection to IP65/NEMA 4. Note that the Ethernet
and SD card options are not available in combination with the weatherproof version.
The Optidew Bench Top is designed to be easy to handle and transport, and is ideal for
laboratory or service use. It has a 5.7” touch screen LCD equipped as standard.

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INTRODUCTION
1.2 Optidew Sensor
The new Optidew sensor is available with either a single or dual stage thermoelectric
cooler and with a choice of sensor head materials making it suitable for use in air/inert
gases or in corrosive environments. The following tables show the capabilities of each
sensor type:
Single Stage
Standard Sensor
Dual Stage
Standard Sensor
Harsh
Environment
Sensor
Approximate
maximum
depression at
ambient
108°F/60°C 126°F/70°C 126°F/70°C
Maximum operating
temperature 194°F/90°C 194°F/90°C 248°F/120°C
Lowest Measurable Dewpoint
Sensor temperature
at 23°C ambient -13°F/-25°C -40°F/-40°C -40°F/-40°C
For more detailed information on the performance of the sensor across its whole
operating temperature range, see section 4.5.
All versions are rated for use at pressure up to 362 psig (2500 kPag).

Optidew User’s Manual
Kahn Instruments 3
INSTALLATION
2 INSTALLATION
2.1 Mounting
Optidew Wall Mount
The Optidew can be wall mounted using the four mounting points on each corner
(see figure 2 for mounting point dimensions). It is possible to install the Optidew Wall
Mount outside, providing it is shielded from direct sunlight and the climate is within the
environmental requirements listed in Appendix A Technical Specifications. It is highly
recommended to choose the weatherproof option if the installation will be outdoors.
Installation
Install using quantity 4 machine screws + washer. Unit must be secured to a solid
surface (e.g. brick, concrete, wood min 0.4"/10mm thick) or to a metal chassis plate of
minimum 0.12"/3mm thickness.
9.4
(240)
10.2
(260)
5.7
(145)
7.1
(180)
Figure 2 Optidew Wall Mount mounting points
Optidew Bench Top
The Optidew Bench Top is designed to be placed on a bench or table to operate.
Alternatively it can be used directly from within the optional Transport Case.

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INSTALLATION
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Optidew User’s Manual
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INSTALLATION
2.2 Instrument Connections
2.2.1 Optidew Wall Mount
Front Panel (Display version)
1
Figure 3 Optidew Wall Mount display front panel
Number Description
1
Display
Shows measured and calculated parameters, controls all
instrument settings and functionality.

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INSTALLATION
Front Panel (Non-display version)
1
Figure 4 Optidew Wall Mount non-display front panel
Number Description
1DCC Control/ Status indicator
2
4
3
5
6 8
7
1
Figure 5 Optidew Wall Mount bottom panel
Bottom Panel
Number Description
1Power Connector
2Sensor Cable connector
3Temperature probe cable connector
4Pressure transmitter cable connector
5Alarm contacts connector
6RS485 and analog output connector
7SD Card slot (optional)
8Ethernet port (optional)
2

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INSTALLATION
2.2.2 Optidew Bench Top
Top Panel
1
Figure 6 Optidew Bench Top top panel
Number Description
1Display
1
Figure 7 Optidew Bench Top left side panel
Left Side Panel
Number Description
1Power Connector
2Power Switch

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INSTALLATION
1
Figure 8 Optidew Bench Top right side panel
Right Side Panel
Number Description
1SD Card slot
12
3
5
4
6
7
Figure 9 Optidew Bench Top rear panel
Rear Panel
Number Description
1Sensor Cable connector
2Temperature probe cable connector
3Pressure transmitter cable connector
4Alarm contacts connector
5RS485 and analog output connector
6USB port
7Ethernet port (optional)

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INSTALLATION
2.3 Electrical Connections
2.3.1 Electrical Supply
WARNING:
The instrument must be GROUNDED
The Optidew accepts a power supply of the following specification:
Voltage 100-240V AC
Frequency 50 – 60Hz
Power Consumption 30VA max
See Appendix A, Technical Specification, for full operating parameters.
Optidew Wall Mount
The wall mount is supplied with a connector wired to a 6 foot cable.
This power connector is wired as follows:
NOTE: The Optidew Wall Mount is designed for continuous operation and therefore does
not feature a power on/off switch. As soon as power is applied, the display (or DCC
button on the transmitter version) will illuminate and the transmitter will initiate a DCC
cycle. Refer to Section 4.4.1.
Replacement power cables are available - contact Kahn Instruments.
Optidew Bench Top
The Optidew Bench Top is supplied with a 6 foot IEC cable. The IEC socket on the side
of the instrument features an integrated ON/OFF switch.
Fuse
This product is provided with an externally mounted fuse located next to the power
connector.

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INSTALLATION
The fuse is rated at 5 x 20mm medium acting:
Power 230 V AC 2.5 A
A replacement fuse can be obtained by contacting Kahn Instruments Service Department.
Equipment Ratings
This product is designed to be safe at least under the following conditions: between a
temperature range of -40°F/C to +140°F/+60°C, in maximum 80% relative humidity
for temperatures up to +88°F/+31°C decreasing linearly to 50% RH at +122°F/+50°C.
Overvoltage Category II. Pollution Degree 2. Altitudes up to 2000m. Indoor use only but
an IP65 unit is offered as an option.
See Appendix A, Technical Specification, for full operating parameters.
2.3.2 Analog and Digital Communications
Note: When using screened cable, the screen should only be connected to a ground
point at either the Optidew installation side, or at the receiving equipment. Failure to
observe this precaution can result in ground loops and equipment malfunction.
2.3.2.1Digital Communications
Figure 10 RS485 & analog output connector
The leftmost four pins of this connector are used for RS485 communications.
Pin Label Description
GND Ground
RS485 A RS485 Data A
RS485 B RS485 Data B
GND Ground
The Optidew provides Modbus RTU over RS485 or USB (Bench Top only). An Ethernet
module is optionally available for both instruments, and provides Modbus TCP
communication.
The Modbus register map can be found in Appendix B.
The application software provided can be used to communicate with the instrument.

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Kahn Instruments 11
INSTALLATION
Refer to the Application Software section at the end of the manual.
2.3.2.2 Current Outputs
Figure 11 Analog output connector
The rightmost four of the pins on this connector are used for mA outputs.
See section 3.2 for information on configuring the analog outputs
Pin Label Description
mA2 Channel 2 Current Output
GND Channel 2 Ground
mA1 Channel 1 Current Output
GND Channel 1 Ground
2.3.2.3 Relay Contacts
There are two sets of relay contacts available via the output connector:
Process Alarm (Relay 1)
This relay changes state to indicate that the process variable has exceeded the alarm
set point value. See section 3.2 for details on how to configure the process alarm trip
criteria. This alarm can also be used to give an early indication that the optics require
cleaning.
System Alarm (Relay 2)
This relay changes state to indicate a fault has occurred which requires operator
intervention. See section 4.6 for detailed information on faults.
Figure 12 Relay contact connector