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Micro Continuous Emission Monitor
Operation & Maintenance Manual
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Revision 2.36, July 1, 2004
Part Number 1021021-100
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Rosemount Analytical UCEM Continuous Analyzer Transmitter
CONTENTS
Preface
Intended Use Statement …………………………………………………………………………….. 1
Safety Summary ……………………………………………………………………………………… 1
Specifications – Analysis Enclosure: General …………………………………………………….. 4
Specifications – Probe/Sample Handling Enclosure: General ..………………………………… 5
Customer Service, Technical Assistance and Field Service ………..………………………….. 6
Returning Parts to the Factory………………………………………………………………………. 6
Training ………………………………………………………………………………………………... 7
1. Introduction......................................................................... 1–3
1.1 Overview..........................................................................................................................1–3
1.2 Time Shared Option.........................................................................................................1–5
1.3 Theory of Operation.........................................................................................................1–7
1.3.1 NOx..................................................................................................................................1–7
1.3.2 CO ...................................................................................................................................1–7
1.3.3 O2....................................................................................................................................1–8
1.3.4 SO2..................................................................................................................................1–9
2. Detector Methodologies..................................................... 2–1
2.1 Non-Dispersive Infrared (NDIR).......................................................................................2–1
2.1.1 Interference Filter Correlation Method.............................................................................2–1
2.1.2 Opto-Pneumatic Method..................................................................................................2–2
2.1.3 Overall NDIR Method.......................................................................................................2–4
2.2 Paramagnetic Oxygen Method........................................................................................2–5
2.3 Electrochemical Oxygen Method.....................................................................................2–6
3. Installation........................................................................... 3–1
3.1 Specifications...................................................................................................................3–1
3.2 Process and Calibration Gas Connection........................................................................3–9
3.2.1 Gas Conditioning...........................................................................................................3–10
3.3 Installation........................................................................................................................3–1
3.3.1 Location...........................................................................................................................3–1
3.3.2 Limitations........................................................................................................................3–1
3.3.3 Mounting Options.............................................................................................................3–1
3.3.4 Electrical Connections.....................................................................................................3–1
3.3.4.1 Circular Connector Assembly Instructions.......................................................................3–3
3.3.4.2 EXT I/O Interface Connector ...........................................................................................3–4
3.3.4.3 SHU #1 / #2 Interface Connector.....................................................................................3–6
3.3.4.4 COM Interface Connector................................................................................................3–7
3.3.4.5 Lan Interface Connector..................................................................................................3–1
3.3.4.6 CPU I/O Interface Connector...........................................................................................3–1
3.3.4.7 SSU Power Connector, T/S units Only............................................................................3–2
3.3.4.8 AC Power Connector.......................................................................................................3–2
3.3.5 Analytical Leak Check .....................................................................................................3–3
3.3.5.1 Flow Indicator Method .....................................................................................................3–1
3.3.5.2 Manometer Method..........................................................................................................3–1
3.3.5.3 Troubleshooting Leaks ....................................................................................................3–3
4. Startup and Operation.........................................................4-1
4.1 Startup Procedure............................................................................................................ 4-1
Rosemount Analytical µCEM Continuous Analyzer Transmitter 2
CONTENTS
4.2 Analyzer Operation.......................................................................................................... 4-2
4.2.1 User Interface (Pocket PC Connection and Program Restore)........................................4-2
4.2.2 µCEM Main Window.........................................................................................................4-3
4.2.3 µCEM Menus............................................................................................................... 4-5
4.2.4 µCEM Alarms................................................................................................................... 4-7
4.2.5
4.2.6 µCEM Login-Current User Indication..............................................................................4-10
4.2.7 Stream Switching Control...............................................................................................4-11
4.3 µCEM Settings...............................................................................................................4-12
4.3.1 µCEM Settings-Range....................................................................................................4-12
4.3.2 µCEM Settings-Auto Calibration.....................................................................................4-14
4.3.3 µCEM Settings - Auto Calibration Time and Frequency.................................................4-15
4.3.4 µCEM Settings-Limits ..................................................................................................4-175
4.3.5 µCEM Settings-Calibration Gas....................................................................................4-196
4.3.6
1918
4.3.7 µCEM Settings-Manual Calibration.............................................................................4-2018
4.3.8 µCEM Settings-Auto Calibration Dialog .....................................................................4-1619
4.4 µCEM Administration....................................................................................................... 4-2
4.4.1 µCEM Administration-User Settings.................................................................................4-2
4.4.2 µCEM Administration-Auto Logoff ....................................................................................4-3
4.5 µCEM Factory and User Settings.................................................................................... 4-4
4.6 uCEM Data Logs ............................................................................................................. 4-7
4.6.1 Maximum Log File Size ....................................................................................................4-7
4.6.2 Maximum Number of Log Files.........................................................................................4-7
4.6.3 Log File Name Format......................................................................................................4-7
4.6.4 Measurement Log File Format..........................................................................................4-8
4.6.5 Calibration Log File Format ..............................................................................................4-8
4.6.6 Alarm Log File Format....................................................................................................4-10
4.6.7 Accessing the Real-Time ACSII Data String via Ethernet TCP/IP (DAS).....................4-101
4.7 Viewing µCEM Data and Diagnotics with the Pocket PC Web Browser..........................4-1
4.8 Viewing µCEM Data with a Web Browser........................................................................ 4-1
4.8.1 Real-Time Page................................................................................................................4-3
4.8.2 Emissions Page................................................................................................................4-4
4.8.3 Download Page ................................................................................................................4-7
4.9 Viewing µCEM Data with MS Excel................................................................................. 4-8
4.10 Auto Calibration............................................................................................................... 4-1
µ
CEM Login......................................................................................................................4-9
µCEM Settings-Maintenance Mode 4-
5. Maintenance and Service....................................................5-1
5.1 Overview.......................................................................................................................... 5-1
5.2 Converter......................................................................................................................... 5-2
5.3 Ozonator.......................................................................................................................... 5-2
5.4 Personality Modules ........................................................................................................ 5-2
5.5 Detector Assembly........................................................................................................... 5-3
5.6 Central Processing Unit................................................................................................... 5-6
5.6.1.1 Features........................................................................................................................... 5-6
5.6.1.2 EMBEDDED ENHANCED BIOS:..................................................................................... 5-7
5.6.2 Analog/Digital I/O Board...................................................................................................5-7
5.6.2.1 Automatic Calibration....................................................................................................... 5-8
5.6.2.2 Analog Inputs................................................................................................................... 5-8
5.6.2.3 Programmable Input Ranges........................................................................................... 5-9
5.6.2.4 Enhanced Trigger and Sampling Control Signals............................................................ 5-9
5.6.2.5 Analog Outputs................................................................................................................ 5-9
5.6.2.6 FIFO and 16-Bit Bus Interface......................................................................................... 5-9
Rosemount Analytical µCEM Continuous Analyzer Transmitter 3
CONTENTS
5.6.2.7 Specifications................................................................................................................. 5-10
5.6.3 PCMCIA Adapter............................................................................................................5-11
5.6.3.1 Features......................................................................................................................... 5-12
5.6.3.2 SOFTWARE FEATURES:............................................................................................. 5-12
5.6.4 Modem............................................................................................................................5-12
5.6.4.1 Features......................................................................................................................... 5-13
5.6.5 Flash Drive........................................................................................................................5-1
5.6.5.1 Specifications................................................................................................................... 5-1
5.6.6 Pocket PC.........................................................................................................................5-1
5.6.7 Wireless LAN Adapter ......................................................................................................5-2
5.6.8 500 Watts Power Supply ..................................................................................................5-3
5.6.8.1 FEATURES...................................................................................................................... 5-3
5.7 Replacement Parts.......................................................................................................... 5-4
5.7.1 Replacement Part list........................................................................................................5-4
5.8 System Enclosure............................................................................................................ 5-9
5.9 Trouble LED................................................................................................................... 5-10
6. µCEM Software .................................................................... 6-1
6.1 µCEM User Interface Software........................................................................................ 6-1
6.2 µCEM Web Server Software............................................................................................ 6-1
6.3 Software Development Management .............................................................................. 6-2
6.4 µCEM Pocket PC Connection Failure.............................................................................. 6-3
Rosemount Analytical µCEM Continuous Analyzer Transmitter 4
PREFACE
PREFACE
I
NTENDED USE STATEMENT
The µCEM Continuous Emission Monitoring Gas Analyzer is intended for use as an
industrial process measurement device only. It is not intended for use in medical,
diagnostic, or life support applications, and no independent agency certifications or
approvals are to be implied as covering such applications.
SAFETY SUMMARY
DANGER is used to indicate the presence of a hazard which will cause severe
personal injury, death, or substantial property damage if the warning is ignored.
WARNING is used to indicate the presence of a hazard which can cause severe
personal injury, death, or substantial property damage if the warning is ignored.
CAUTION is used to indicate the presence of a hazard which will or can cause minor
personal injury or property damage if the warning is ignored.
NOTE IS USED TO INDICATE INSTALLATION, OPERATION, OR MAINTENANCE INFORMATION
WHICH IS IMPORTANT BUT NOT HAZARD RELATED
.
DANGER: ALL PERSONNEL AUTHORIZED TO INSTALL,
OPERATE AND SERVICE THIS EQUIPMENT
To avoid explosion, loss of life, personal injury and damage to this equipment
and on-site property, do not operate or service this instrument before reading
and understanding this instruction manual and receiving appropriate training.
Save these instructions.
If this equipment is used in a manner not specified in these instructions,
protective systems may be impaired.
WARNING: DEVICE CERTIFICATION(S)
Any addition, substitution, or replacement of components installed on or in this
device, must be certified to meet the hazardous area classification that the
device was certified to prior to any such component addition, substitution, or
replacement. In addition, the installation of such device or devices must meet
the requirements specified and defined by the hazardous area classification of
the unmodified device. Any modifications to the device not meeting these
requirements, will void the product certification(s).
Rosemount Analytical µCEM Continuous Analyzer Transmitter 1
PREFACE
DANGER: TOXIC GAS
This device may contain explosive, toxic or unhealthy gas components. Before
cleaning or changing parts in the gas paths, purge the gas lines with ambient air
or nitrogen.
+
WARNING: ELECTRICAL SHOCK HAZARD
POSSIBLE EXPLOSION HAZARD
Do not open while energized. Do not operate without dome and covers secure.
Installation requires access to live parts which can cause death or serious injury.
WARNING: ELECTRICAL SHOCK HAZARD
For safety and proper performance this instrument must be connected to a
properly grounded three-wire source of power.
WARNING: POSSIBLE EXPLOSION HAZARD
Ensure that all gas connections are made as labeled and are leak free. Improper
gas connections could result in explosion and death.
WARNING: TOXIC GAS
This unit’s exhaust may contain hydrocarbons and other toxic gases such as
carbon monoxide. Carbon monoxide is highly toxic and can cause headache,
nausea, loss
Avoid inhalation of the exhaust gases at the exhaust fitting.
of consciousness, and death.
Connect exhaust outlet to a safe vent using stainless steel or Teflon line. Check
vent line and connections for leakage.
Keep all tube fittings tight to avoid leaks. See Section 3.3.5 for leak test
information.
Rosemount Analytical µCEM Continuous Analyzer Transmitter 2
PREFACE
WARNING: PARTS INTEGRITY AND UPGRADES
Tampering with or unauthorized substitution of components may adversely
affect the safety of this instrument. Use only factory approved components for
repair.
Because of the danger of introducing additional hazards, do not perform any
unauthorized modification to this instrument.
Return the instrument to a Rosemount Analytical Service office for service or
repair to ensure that safety features are maintained.
CAUTION: PRESSURIZED GAS
This unit requires periodic calibration with a known standard gas. It also may
utilize a pressurized carrier gas, such as helium, hydrogen, or nitrogen. See
General Precautions for Handling and Storing High Pressure Gas Cylinders at the
rear of this manual.
CAUTION: HEAVY WEIGHT
U
SE TWO PERSONS OR A SUITABLE LIFTING DEVICE TO MOVE OR
CARRY THE INSTRUMENT
.
Rosemount Analytical µCEM Continuous Analyzer Transmitter 3
SPECIFICATIONS – GENERAL
SPECIFICATIONS – Analysis Enclosure: GENERAL
Power: Universal Power Supply 85 – 125 VAC, 50 – 60 Hz, + 10%, 1000 Watts
Maximum at Start Up. 500 Watts Nominal
MicroProcessor: Intel Celeron processor, 566MHz, 64MB RAM, PC/104 architecture,
Windows NT embedded Platform
Pocket PC: 206MHz, StrongArm processor, 32MB RAM 32 ROM, 240 X 320 pixels LCD,
TFT color, backlit, Wireless LAN optional
PREFACE
Detectors//Number: NDIR (CO), UV (SO2), Paramagnetic (O2), Electrochemical (O2),
Chemiluminscent (NOx) // Up to three in one analyzer
Mounting: Wall Mount
Area Classification: General Purpose / NEMA 4X Fiberglass Enclosure Compliant
Compliance's: CSA (Pending)
Ambient Temperature Range: -300 to 500 Celsius.
Relative Humidity: 5 to 99%
Inputs/Outputs: The complete I/O list with terminal locations is located in section
3.3.4
Digital:
RS-485 Serial Port. (Multi-Drop Network)
RS-232 Serial Port.
LAN, Ethernet 10/100-BaseT
Connectivity Protocols:
HTML (Web Browser) – Status, file transfer Modem / Web browser
TCP/IP, MTTP ASCII String
Microsoft Shared drive
FTP Logs download
TELNET Server
Rosemount Analytical µCEM Continuous Analyzer Transmitter 4
PREFACE
Analog:
Analog Outputs: Qty. 3 Isolated 4-20 mA dc, 500 ohms Max Load (O2, CO or SO2,
NOx)
*Optional: Additional Qty. 3 (Extended I/O option)
Analog Inputs: Qty 2 (Typically; MW, Fuel Flow)
*Optional: Additional Qty. 2 (Extended I/O option)
Digital
Outputs:
Following are connected directly to the MicroCEM Probe/Sample Handling Box:
Sample Pump on/off, Drain Pump on/off, Purge on/off, Calibrate on/off – All are rated
110VAC @ 1amp Dry Contact.
Qty. 6 dry contact digital Outputs
*Optional Time Share option – Dry Contact used for Stream Indicator.
Digital Inputs:
Qty. 3: (Typical Process on/off, Flame Detect, Shutdown or Initiate Cal)
*Optional three additional Inputs (Extended I/O)
Instrument Weight: 62 lbs Typical
Size: 24“ X 20“ X 12“ (H W D)
Ranges:
O2: 0 –2 Selectable to 0 –25% (1% increments)
Sample Temperature: 0 degrees C to 55 degrees C
Sample flow rate: .5 to 1.5 liters/min
Warm Up Time: Max 25 minutes @ low ambient temperatures
Linearity
Zero Drift
Span Drift
Repeatability
Response Time (t90)
Influence of Ambient
Temperature
(-20C to 45C)
-On Zero
-On Span
CO: 0 –100ppm Selectable to 1000ppm (1ppm increments)
NOx: 0 – 10ppm Selectable to 1000ppm (1ppm increments)
Paramagnetic
)
O
2
<+/- 1% < +/- 1% < +/- 1% < +/- 1%
< +/- 1% /day < +/- 1% /day < +/- 1% /day < +/- 1% /day
< +/- 1% /day < +/- 1% /day < +/- 1% /day < +/- 1% /day
< +/- 1% < +/- 1% < +/- 1% < +/- 1%/day
10< +/-t90< +/-15 10< +/-t90< +/-15
< +/-1%
< +/-1%
Electro
Chemical O
< +/-1%
< +/-1%
2
NDIR
CO
15s< +/-t
30s
< +/-2%
< +/-2%
90
< +/-
Chemiluminescent
15s< +/-t
< +/-2%
< +/-2%
NOx
< +/-30s
90
(1)
(1)
(1)
(1)
(1)
0-10ppm NOx range is <+/- 3%.
Rosemount Analytical µCEM Continuous Analyzer Transmitter 5
INTRODUCTION
SPECIFICATIONS – Probe/Sample Handling Enclosure: GENERAL
See separate SHS manual for more details
Power: Universal Power Supply 85 – 125 VAC, 50 – 60 Hz, + 10%
750 Watts Maximum at Start Up. 500 Watts Nominal
Mounting: Customer Flange Mount (2 Hole Top) or Wall Mount for High Temp Option
Area Classification: General Purpose / NEMA 4X Fiberglass Enclosure
Compliance's: CSA (Pending)
Ambient Range Temperature: -300 to 500 Celsius
Relative Hum: 5 to 99%
Instrument Weight: 95 lbs Typical
Size: 24“ X 34“ X 12“ (H W D)
Stack Sample Moisture: Up to 25% max
Sample Cooler: Thermo Electric dual pass Chiller. Permeation Tube (-30 degrees C.
Dewpoint. Customer instrument air required @ 5 L/M, -40 degree C dewpoint
Max. Stack Temperature: Standard 4000 F.
Optional: 600 F (available with elongated spool option)
High Temp: 1400 F (Off Stack Option)
Stack Pressure: Typical -5 to 15 inches H2O
Sample Flow Rate: 500 to 2500cc/min
Response Time: Maximum distance between Analysis Enclosure and Sample
Conditioning/Probe Enclosure is 300'. (Response time is 30 seconds/100' w/1/4"
tubing)..
Probe Length: 48" length 316 SS Probe with .5 micron sintered filter. Customer to cut
to length in field if necessary. Optional 5’ and 6’ probes.
Mounting Flange: Standard 4“ 150# Raised Face. Shipped Equipped with Gasket
Sample Pump: 316 SS diaphragm type
Instrument Air Requirements: Instrument grade air required. 15 SCFM @ 60 -100 PSIG (30
seconds 2 times per day) Pressure Regulation by Customer
Rosemount Analytical µCEM Continuous Analyzer Transmitter 1–1
INTRODUCTION
CUSTOM ER SERVICE, TECHNICAL ASSIST ANCE AND FIELD SER VICE
For order administration, replacement parts, application assistance, on-site or factory
repair, service or maintenance contract information, contact:
Rosemount Analytical Inc.
Process Analytical Division
Customer Service Center
1-800-433-6076
RETURNING PARTS TO THE FACTORY
Before returning parts, contact the Customer Service Center and request a Returned
Materials Authorization (RMA) number. Please have the following information when you
call: Model Number, Serial Number, and Purchase Order Number or Sales Order
Number.
Prior authorization by the factory must be obtained before returned materials will be
accepted. Unauthorized returns will be returned to the sender, freight collect.
When returning any product or component that has been exposed to a toxic, corrosive
or other hazardous material or used in such a hazardous environment, the user must
attach an appropriate Material Safety Data Sheet (M.S.D.S.) or a written certification
that the material has been decontaminated, disinfected and/or detoxified.
Return to:
Rosemount Analytical Inc.
1201 North Main St.
Orrville, OH 44667
USA
TRAINING
A comprehensive Factory Training Program of operator and service classes is
available. For a copy of the Current Operator and Service Training Schedule contact
the Technical Services Department at:
Rosemount Analytical Inc.
Phone: 1-330-682-9010
COMPLIANCES
This product may carry approvals from several certifying agencies. The certification
marks appear on the product name-rating plate.
NOTES
Rosemount Analytical µCEM Continuous Analyzer Transmitter 1–2
INTRODUCTION
1. Introduction
1.1 Overview
This manual describes the Rosemount Analytical Micro Continuous Emission
Monitoring (µCEM) gas Analyzer Module.
The µCEM Analyzer Module is designed to continuously determine the concentration of
O2, CO, SO2, and NOx in a flowing gaseous mixture. The concentration is expressed
in percent or parts-per-million.
The sampled gas is collected from the stack and prepared by the Probe/Sample
Handling Enclosure for analysis and processing by the Analysis Enclosure. The
ANALYSIS ENCLOSURE is a stand alone, computer-controlled unit, utilizing PC/104
as the system bus. The uCEM is enclosed in rugged NEMA 4X, IP65 type enclosures,
for harsh environment. The ANALYSIS ENCLOSURE utilizes convection cooling with
no air intake and air vents. The ANALYSIS ENCLOSURE is modular, general purpose
and easily expandable. It utilizes industry standard components such as PC/104
boards, and modular signal conditioning modules.
Rosemount Analytical µCEM Continuous Analyzer Transmitter 1–3
INTRODUCTION
Figure 1-1. µCEM Micro Continuous Emission Monitoring – Analysis Enclosure
Rosemount Analytical µCEM Continuous Analyzer Transmitter 1–4
INTRODUCTION
Figure 1-2. µCEM Micro Continuous Emission Monitoring Gas Analyzer with Time
Share option.
1.2 Time Shared Option
Provides the functionality to monitor and process sample gases from two streams on a
time-share scheme. This option allows you to connect one uCEM to two Sample
Handling units.
Rosemount Analytical µCEM Continuous Analyzer Transmitter 1–5
TV1
INTRODUCTION
FROM
uCEM CAL
TO uCEM
SAMPLE
TO SHU1
CAL GAS
TO SHU2
CAL GAS
FROM SHU1
SAMPLE
FROM SHU2
SAMPLE
EXHAUST
TV2
TV3
TV4
Figure 1-3. Time Share option Flow Diagram
Rosemount Analytical µCEM Continuous Analyzer Transmitter 1–6
INTRODUCTION
1.3 Theory of Operation
1.3.1 NOx
The NOx analyzer continuously analyzes a flowing gas sample for NOx [nitric oxide
(NO) plus nitrogen dioxide (NO2)]. The sum of the concentrations is continuously
reported as NOx.
The µCEM NOx Analyzer Module uses the chemiluminecence method of detection.
This technology is based on NO’s reaction with ozone (O3) to produce NO2 and oxygen
(O2). Some of the NO2 molecules produced are in an electronically excited state (NO2*
where the * refers to the excitation). These revert to the ground state, with emission of
photons (essentially, red light). The reactions involved are:
1.3.2 CO
NO2 + O3 → NO2* + O
2
NO2* → NO2 + red light
The sample is continuously passed through a heated bed of vitreous carbon, in which
NO2 is reduced to NO. Any NO initially present in the sample passes through the
converter unchanged, and any NO2 is converted to an approximately equivalent (95%)
amount of NO.
The NO is quantitatively converted to NO2 by gas-phase oxidation with molecular
ozone produced within the analyzer from air supplied by an external source. During the
reaction, approximately 10% of the NO2 molecules are elevated to an electronically
excited state, followed by immediate decay to the non-excited state, accompanied by
emission of photons. These photons are detected by a photomultiplier tube which
produces an output proportional to the concentration of NOx in the sample.
To minimize system response time, an internal sample bypass feature provides highvelocity sample flow through the analyzer.
The optical bench can selectively measure multiple components in a compact design by using a
unique dual optical bench design. Depending on the application, any two combinations of NDIR
channels can be combined on a single chopper motor/dual source assembly.
Other application-dependent options include a wide range of sample cell materials, optical filters and
solid state detectors. The NDIR Microflow detector consists of two chambers, measurement and
reference with an interconnected path in which an ultra low flow filament sensor is mounted. During
operation, a pulsating flow occurs between the two chambers which is dependent upon: sample gas
absorption, modulation by the chopper motor and the fill gas of the detector chambers. The gas
flow/sensor output is proportional to the measured gas concentration. The optical bench is further
enhanced by a novel “Look-through” detector technique. This design allows two detectors to be
arranged in series --- enabling two different components to be measured on a single optical bench.
The optical bench contains a unique eddy current drive chopper motor and source assembly. This
design incorporates on board “intelligence” to provide continuous “self test” diagnostics.
Rosemount Analytical µCEM Continuous Analyzer Transmitter 1–7
1.3.3 O2
Paramagnetic: The determination of oxygen is based on the measurement of the magnetic
susceptibility of the sample gas. Oxygen is strongly paramagnetic, while other common gases
are not. The detector used is compact, has fast response and a wide dynamic range. The long
life cell is corrosion resistant, heated and may be easily cleaned. It has rugged self-tensioning
suspension and is of welded Non-Glued construction.
INTRODUCTION
Rosemount Analytical µCEM Continuous Analyzer Transmitter 1–8
1.3.4 SO2
INTRODUCTION
The optical bench can selectively measure multiple components in a compact design by using a
unique dual optical bench design. Depending on the application, any two combinations of NDIR
channels can be combined on a single chopper motor/dual source assembly.
Other application-dependent options include a wide range of sample cell materials, optical filters
and solid state detectors. The NDIR Microflow detector consists of two chambers, measurement
and reference with an interconnected path in which an ultra low flow filament sensor is mounted
during operation, a pulsating flow occurs between the two chambers which is dependent upon:
sample gas absorption, modulation by the chopper motor and the fill gas of the detector
chambers. The gas flow/sensor output is proportional to the measured gas concentration. The
optical bench is further enhanced by a novel “Look-through” detector technique. This design
allows two detectors to be arranged in series --- enabling two different components to be
measured on a single optical bench. The optical bench contains a unique eddy current drive
chopper motor and source assembly. This design incorporates on board “intelligence” to provide
continuous “self test” diagnostics.
Rosemount Analytical µCEM Continuous Analyzer Transmitter 1–9
Detector Methodologies
2. Detector Methodologies
The µCEM can employ up to three different measuring methods depending on the
configuration chosen. The methods are: NDIR CO/SO2, Paramagnetic O
Electrochemical O2, and chemiluminescent NOx.
2.1 Non-Dispersive Infrared (NDIR)
The non-dispersive infrared method is based on the principle of absorption of infrared
radiation by the sample gas being measured. The gas-specific wavelengths of the
absorption bands characterize the type of gas while the strength of the absorption gives
a measure of the concentration of the gas component being measured.
An optical bench is employed comprising an infrared light source, two analysis cells
(reference and measurement), a chopper wheel to alternate the radiation intensity
between the reference and measurement side, and a photometer detector. The
detector signal thus alternates between concentration dependent and concentration
independent values. The difference between the two is a reliable measure of the
concentration of the absorbing gas component.
Depending on the gas being measured and its concentration, one of two different
measuring methods may be used as follows:
,
2
2.1.1 Interference Filter Correlation Method
With the IFC method the analysis cell is alternately illuminated with filtered infrared
concentrated in one of two spectrally separated wavelength ranges. One of these two
wavelength bands is chosen to coincide with an absorption band of the sample gas and
the other is chosen such that none of the gas constituents expected to be encountered
in practice absorbs anywhere within the band.
The spectral transmittance curves of the interference filters used in the µCEM analyzer
and the spectral absorption of the gases CO and CO2 are shown in Figure 2-1 below. It
can be seen that the absorption bands of these gases each coincide with the
passbands of one of the interference filters. The forth interference filter, used for
generating a reference signal, has its passband in a spectral region where none of
these gases absorb. Most of the other gases of interest also do not absorb within the
passband of this reference filter.
The signal generation is accomplished with a pyroelectrical (solid-state) detector. The
detector records the incoming infrared radiation. This radiation is reduced by the
absorption of the gas at the corresponding wavelengths. By comparing the
measurement and reference wavelength, an alternating voltage signal is produced.
This signal results from the cooling and heating of the pyroelectric detector material.
Rosemount Analytical µCEM Continuous Analyzer Transmitter 2–1
DETECTOR METHODOLOGIES
Figure 2-1. Absorption Bands of Sample Gas and Transmittance of Interference Filters
2.1.2 Opto-Pneumatic Method
In the opto-pneumatic method, a thermal radiator generates the infrared radiation which
passes through the chopper wheel. This radiation alternately passes through the filter
cell and reaches the measuring and reference side of the analysis cell with equal
intensity. After passing another filter cell, the radiation reaches the pneumatic detector.
The pneumatic detector compares and evaluates the radiation from the measuring and
reference sides of the analysis cell and converts them into voltage signals proportional
to their respective intensity.
The pneumatic detector consists of a gas-filled absorption chamber and a
compensation chamber which are connected by a flow channel in which a Microflow
filament sensor is mounted. This is shown in Figure 2-2 below.
In principle the detector is filled with the infrared active gas to be measured and is only
sensitive to this distinct gas with its characteristic absorption spectrum. The absorption
chamber is sealed with a window which is transparent for infrared radiation. The
window is usually Calcium Fluoride (CaF
).
2
When the infrared radiation passes through the reference side of the analysis cell into
the detector, no pre-absorption occurs. Thus, the gas inside the absorption chamber is
heated, expands and some of it passes through the flow channel into the compensation
chamber.
Rosemount Analytical µCEM Continuous Analyzer Transmitter 2–2
A
DETECTOR METHODOLOGIES
bsorption chamber
CaF
Window
Flow channel with
Microflow sensor
2
Compensation chamber
Figure 2-2. Opto-Pneumatic Gas Detector
When the infrared radiation passes through the open measurement side of the analysis
cell into the detector, a part of it is absorbed depending on the gas concentration. The
gas in the absorption chamber is, therefore, heated less than in the case of radiation
coming from the reference side. Absorption chamber gas becomes cooler, gas
pressure in the absorption chamber is reduced and some gas from the compensation
chamber passes through the flow channel into the absorption chamber.
The flow channel geometry is designed in such a way that it hardly impedes the gas
flow by restriction. Due to the radiation of the chopper wheel, the different radiation
intensities lead to periodically repeated flow pulses within the detector.
The Microflow sensor evaluates these flow pulses and converts them into electrical
pulses which are processed into the corresponding analyzer output.
Rosemount Analytical µCEM Continuous Analyzer Transmitter 2–3
DETECTOR METHODOLOGIES
g
(hig
)
(
(
)
2.1.3 Overall NDIR Method
In the case of dual-channel analyzers, the broadband emission from two infrared
sources pass through the chopper wheel. In the case of the Interference Filter
Correlation (IFC) method, the infrared radiation then passes through combinations of
interference filters. In the case of the opto-pneumatic method, the infrared radiation
passes through an optical filter depending on the application and need for reduction of
influences. Then the infrared radiation enters the analysis cells from which it is focused
by filter cells onto the corresponding detector. The preamplifier detector output signal is
then converted into the analytical results expressed directly in the appropriate physical
concentration units such as percent volume, ppm, mg/Nm3, etc. This is shown in Figure
2-3 below.
MOTOR
Light source
Chopper
blade
Analysis cell
measurin
Analysis cell
reference side
Gas detector
side
Filter cell
Duplex filter disc
Adapter cell
h measuring range
Analysis cell
undivided)
Filter cell
Preamplifier
Pyroelectric detector
solid-state detector
Preamplifier
Chopper
blade
Figure 2-3. Overall NDIR Method
Rosemount Analytical µCEM Continuous Analyzer Transmitter 2–4
DETECTOR METHODOLOGIES
2.2 Paramagnetic Oxygen Method
The paramagnetic principle refers to the induction of a weak magnetic field, parallel and
proportional to the intensity of a stronger magnetizing field.
The paramagnetic method of determination of oxygen concentration utilizes nitrogen
filled quartz spheres arranged at opposite ends of a bar, the center of which is
suspended by and free to rotate on a thin platinum wire ribbon in a cell. Nitrogen (N2) is
used because it is diamagnetic or repelled by a magnet.
A small mirror that reflects a light beam coming from a light source to a photodetector,
is mounted on the platinum ribbon. A strong permanent magnet specifically shaped to
produce a strong, highly inhomogeneous magnetic field inside the analysis cell, is
mounted outside the wall of the cell.
When oxygen molecules enter the cell, their paramagnetism will cause them to be
drawn towards the region of greatest magnetic field strength. The oxygen molecules
thus exert different forces on the two suspended nitrogen filled quartz spheres,
producing a torque which causes the mirror to rotate away from its equilibrium position.
The rotated mirror deflects the incident light onto the photodetector creating an
electrical signal which is amplified and fed back to a coil attached to the bar holding the
quartz spheres, forcing the suspended spheres back to the equilibrium position.
The current required to generate the restoring torque to return the quartz bar to its
equilibrium position is a direct measure of the O2 concentration in the sample gas.
The complete paramagnetic analysis cell consists of an analysis chamber, permanent
magnet, processing electronics, and a temperature sensor. The temperature sensor is
used to control a heat exchanger to warm the measuring gas to about 55 °C.
Rosemount Analytical µCEM Continuous Analyzer Transmitter 2–5
DETECTOR METHODOLOGIES
2.3 Electrochemical Oxygen Method
The electrochemical method of determining oxygen concentration is based on the
galvanic cell principle shown in Figure 2-4 below.
Lead wire (Anode)
Lead wire (Cathode)
Anode (1) (Lead)
O-Ring
Plastic disc (9)
Plastic top (10)
Figure 2-4. Electrochemical Oxygen Sensor
(Black)
(Red)
Resistor (6)
Thermistor (5)
Acid electrolyte (3)
Spong3 disc (7)
Cathode (2) (Gold film)
Teflon membrane (4)
The electrochemical oxygen sensor incorporates a lead and gold galvanic process with
a lead anode (1) and a gold cathode (2), using an acid electrolyte (3).
Oxygen molecules diffuse through a non-porous Teflon membrane (4) into the
electrochemical cell and are reduced at the gold cathode. Water is the byproduct of this
reaction.
On the anode, lead oxide is formed which is transferred into the electrolyte. The lead
anode is continuously regenerated and, therefore, the electrode potential remains
unchanged for a long time. The rate of diffusion and corresponding response time (t90)
of the sensor is dependent on the thickness of the Teflon membrane.
The electric current between the electrodes is proportional to the O
concentration in
2
the sample gas being measured. The resultant signal is measured as a voltage across
the resistor (6) and thermistor (5), the latter of which is used for temperature
compensation. A change in the output voltage (mV) represents oxygen concentration.
NOTE: The electrochemical O2 cell requires a minimum internal consumption of
oxygen. Sample gases with an oxygen concentration of less than 2% could result in a
reversible detuning of sensitivity and the output will become unstable. The
recommended practice is to purge the cell with conditioned ambient air between
periods of measurement. If the oxygen concentration is below 2% for several hours or
days, the cell must be regenerated for about one day with ambient air. Temporary
flushing with nitrogen (N
) for less than one hour (analyzer zeroing) will have no effect
2
on the sensitivity or stability.
Rosemount Analytical µCEM Continuous Analyzer Transmitter 2–6
DETECTOR METHODOLOGIES
(Red) V out (Black)
Thermistor (5) Resistor (6)
(-) (+)
Gold Lead
Cathode (2) Anode (1)
O2 + 4 H + 4 e → 2 H2O 2 Pb + 2 H2O → 2PbO + 4 H + 4 e
Electrolyte (3)
(ph 6)
Summary reaction O2+ 2 Pb → 2 PbO
Figure 2-5 Reaction of Galvanic Cell
Rosemount Analytical µCEM Continuous Analyzer Transmitter 2–7
INSTALLATION
3. Installation
WARNING: ELECTRICAL SHOCK HAZARD
Installation and servicing of this device requires access to components
which may present electrical shock and/or mechanical hazards. Refer installation
and servicing to qualified service personnel.
CAUTION: CODE COMPLIANCE
Installation of this device must be made in accordance with all
applicable national and/or local codes. See specific references on installation
drawing located in the rear of this manual.
3.1 Specifications
Electrical Power
See Specifications in Preface
Power Cable
AC Operation: 16 gauge, minimum.
Gas Lines
For external gas lines, the use of all new tubing throughout is strongly recommended.
The preferred type is new, Teflon or Stainless Steel tubing, sealed at the ends.
Services
AC as well as input and output digital and analog signals connect through the circular
connectors located on the bottom of the uCEM enclosures.
Rosemount Analytical µCEM Continuous Analyzer Transmitter 3–1
INSTALLATION
Figure 3-1. Dimensional Drawing, Door closed. Shown with Time Share option
with standard Fiberglass Enclosure.
Rosemount Analytical µCEM Continuous Analyzer Transmitter 3–2
INSTALLATION
41.49
3.0010.28
14.00
Ø
.440
.62
25.24
18.00
Figure 3-2. Dimensional Drawing, Door closed. Shown with Time Share option with Optional
Stainless Steel Enclosure.
32.53
Rosemount Analytical µCEM Continuous Analyzer Transmitter 3–3
SAMPLE INLET
1/2" NPT
FEMALE CONNECTION
INSTALLATION
STACK
SAMPLE FLOW
INSTRUMENT AIR
(BY CUSTOMER)
LEFT SIDE VIEW
ATMOS PRESSURE
DRAIN TO SAFE
LOCATION
CEMS SHS
ENCLOSURE
(24H X 24W X 12D)
FRONT VIEW
INITIATE AUTO CALIBRATION
(3 WIRE CABLE BY CUSTOMER)
SAMPLE FROM
S/C ENCLOSURE
CALIBRATION LINE
TO S/C ENCLOSURE
POWER IN
115 VAC, 60 HZ
5 AMPS
(BY CUSTOMER)
DRY CONTACT
TEFLON TUBING
(BY CUSTOMER)
1/4" O.D.
ANTENNA
PHONE
RS485
uCEM ANALYZER
ENCLOSURE
(24H X 20W X 12D)
LAN
ELECTRICAL INPUT/OUTPUT
CONNECTORS
POWER IN, 115 VAC,
60 HZ, XX AMPS
(BY CUSTOMER)
ANALOG OUTPUT
DIGITAL OUTPUT
RS232
MID RANGE
TUBING/PRESSURE REGULATOR
STATIONS/CALIB GASES
O2/NO
HIGH RANGE
(BY CUSTOMER)
NITROGENO2/NO
Figure Basic Installation Guideline
Rosemount Analytical µCEM Continuous Analyzer Transmitter 3–4
INSTALLATION
CAL GAS
O2 IN
OUT
O2 IN
{
INST
ATMOS
AIR
PRES
BY
DRAIN
CUST
TO SAFE
PLACE
O2 IN
ELECTRICAL
CONNECTIONS
CAL GAS
IN (CUST)
{
INST
ATMOS
AIR
PRES
BY
DRAIN
CUST
TO SAFE
PLACE
ELECTRICAL
CONNECTIONS
Figure Basic Installation Guideline – Time Share Option
Rosemount Analytical µCEM Continuous Analyzer Transmitter 3–5
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