Omega Products RHB-3 Installation Manual

User’s Guide

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RHB-3 and RHB-4

Dew Point Monitor

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Servicing North America:

One Omega Drive, P.O. Box 4047
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e-mail: [e-mail]

976 Bergar
Laval (Quebec) H7L 5A1, Canada
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Sales Service: 1-800-826-6342 / 1-800-TC-OMEGA
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Mexico:

Benelux:

Czech Republic:

France:

Germany/Austria:

United Kingdom:

ISO 9002 Certified

En Espan˜ ol: [phone]-7803 e-mail: [e-mail]
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Servicing Europe:

Postbus 8034, 1180 LA Amstelveen, The Netherlands
TEL: [phone] FAX: [phone]
Toll Free in Benelux: 0800 0993344
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Frystatska 184, 733 01 Karviná, Czech Republic
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Toll Free: 0800-1-66342 e-mail: [e-mail]

11, rue Jacques Cartier, 78280 Guyancourt, France
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Toll Free in France: 0800 466 342
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Daimlerstrasse 26, D-75392 Deckenpfronn, Germany
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One Omega Drive, River Bend Technology Centre
Northbank, Irlam, Manchester
M44 5BD United Kingdom
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Toll Free in United Kingdom: 0800-488-488
e-mail: [e-mail]

It is the policy of OMEGA Engineering, Inc. to comply with all worldwide safety and EMC/EMI
regulations that apply. OMEGA is constantly pursuing certification of its products to the European New
Approach Directives. OMEGA will add the CE mark to every appropriate device upon certification.

The information contained in this document is believed to be correct, but OMEGA accepts no liability for any
errors it contains, and reserves the right to alter specifications without notice.
WARNING: These products are not designed for use in, and should not be used for, human applications.

CONTENTS

TOPIC PAGE

Overview of the RHB-3 and the RHB-4 5

Systems Components 5

Measurement parameters available 6

Available Interfaces 6

ACCUSTAR, self correction feature 6

Theory of Operation 6

Operating from Display 7

Cleaning Mirror 8

Menu Overview 9, 10, 11

Display/Sensor Controls 12

Electrical Connections to Display Module 13

Electrical Connections to the Sensor Chassis 14

RS232 Connection 14, 15

Calibration Analog Outputs 15, 16

Final (NIST) Calibration 16

Overview of the RHB-3

The OMEGA® RHB-3 is a chilled mirror monitor and can be used in a wide variety of
applications. It provides accurate and reliable measurements over an extended range for
long periods of time with the new ACCU-Star self-correcting feature.

• Dew/frost point from 22°C to –40°C @ an ambient temperature of 25°C

• Relative humidity from 0.002% to 100%

The RHB-3 offers a remote multifunction display and can display two selectable
measurements simultaneously, while outputting two selectable analog outputs, one
selectable alarm point and any combination of selected measurements on a serial port.

The RHB-3 is a bench top monitor with panel mount capability.

Three sensing configurations of the RHB-3 are available: dew point, temperature and
pressure.

RHB-3 Specifications

Dew Point Range -40°C to 24°C @25°C

Accuracy +/- 0.2°C

Repeatability +/-0.05°C

Hysteresis None

Temperature (optional) 100 Ohm 4 wire PRT 0.00385 Ohm

Pressure (optional) 4-20mA abs. pressure sensor

Analog

RS232

Alarms

Operating Temperature 0 to 60 deg C

Operating Pressure 0-1Mpa

Power 85 to 265Vac 50/60HZ 100W

Weight 5kg

Sensor dimensions

Meter dimensions

Dual 0-5Vdc & 4-20mA
Any parameters
100mA AC/DC Opto-Isolators

360*110*130mm
210*110*30mm

Overview of the RHB-4

The Shinyei RHB-4 is a chilled mirror monitor and can be used in a wide
variety of applications. It provides accurate and reliable measurements over an extended
range for long periods of time with the new ACCU-Star self-correcting feature.

• Dew/frost point from 22°C to –60°C @ an ambient temperature of 25°C

• Relative humidity from 0.002% to 100%

The RHB-4 offers a remote multifunction display and can display two selectable
measurements simultaneously, while outputting two selectable analog outputs, one
selectable alarm point and any combination of selected measurements on a serial port.

The RHB-4 is a bench top monitor with panel mount capability.

Three sensing configurations of the RHB-4 are available: dew point, temperature and
pressure.

RHB-4 Specifications

Dew Point Range -55°C to 24°C @25°C

Accuracy +/- 0.2°C

Repeatability +/-0.05°C

Hysteresis None

Temperature (optional) 100 Ohm 4 wire PRT 0.00385 Ohm

Pressure (optional) 4-20mA abs. pressure sensor

Analog

RS232

Alarms

Operating Temperature 0 to 60 deg C

Operating Pressure 0-1Mpa

Power 85 to 265Vac 50/60HZ 100W

Weight 5kg

Sensor dimensions

Meter dimensions

Dual 0-5Vdc & 4-20mA
Any parameters
100mA AC/DC Opto-Isolators

360*110*135mm
210*110*30mm

System Components

The complete system consists of the following items:

• The electronic display

• Dew point sensor

• Interconnecting sensor cable

• AC line cord

• Operators manual

• Certificate of Calibration

• Maintenance Kit

• RS232 cable

Measurement parameters available:

Dew Point Degree C or F
Temperature Degree C or F
Pressure kPa, mbar, psia
Relative Humidity %RH
Absolute Humidity PPMv, PPMw, g/m3, grains/lb

Available interfaces are as follows:

• 2 Analog outputs: 0-5V and 4-20mA (all parameters)

• “Analog outputs” may be configured as 0/5 volt and 4/20mA alarms, optional

100mA AC/DC Opto-isolated add-on module available

• Alarm relay: 100mA AC/DC Opto-isolated

• RS-232: Any parameter

• 4-20mA Pressure sensor inputs

• 100 Ohm PRT 4 wire 0.00385 Ohm

Feature:

The ACCU-STAR feature provides automatic contaminations correction allowing
your Dewpoint Monitor to continue providing accurate and reliable measurements over
extended periods of time without having to physically interrupt your measurement
process.

Theory of Operation

Optical condensation hygrometry is a precise technique for determining the water vapor
content in gases by directly measuring dew point or frost temperatures. Using this
technique, a metallic mirror is cooled until it reaches a temperature at which a thin layer
of condensation begins to form on it. The dew layer is detected optically, and the mirror
is held at that temperature. The mirror temperature, measured with a platinum resistance
thermometer, is an accurate indicator of the dew or frost point. Because these
hygrometers are so accurate, they are widely used as a standard in many of the world's
metrology laboratories. The condensate mirror is illuminated with a high-intensity, solid
state, light emitting diode (LED). A photo- detector monitors the LED light reflected
from the mirror. The photo detector is fully illuminated when the mirror is clear of dew,
and it receives less light as dew forms. A separate photo detector is used as a known
reference to compensate for any thermally induced changes in the optical components.
The photo detectors are measured by a microprocessor, the output of the microprocessor
controls the electrical current to the thermoelectric cooler. A high cooler current is sent
when the mirror is dry, causing the mirror to cool toward the dew point. As dew begins to
form on the mirror, less light is reflected, and the current output decreases. A rate
feedback loop within the microprocessor ensures critical response, causing the mirror to
stabilize quickly at a temperature that maintains a thin dew or frost layer on the mirror
surface. A precision thermometer element embedded within the mirror directly monitors
this dew point temperature.