Ametek 888 User manual

Model 888 Tail Gas Analyzer
Class I, Division 2, GPS A, B, C, D
User Manual
PN 883056902 REV. H
Process Instruments
Western Research
455 Corporate Boulevard
Newark, DE 19702

2 | Model 888 Tail Gas Analyzer Class I, Division 2
© 2015 AMETEK Process & Analytical Instruments Division
This document contains Essential Health and Safety information for the use of the AMETEK Model 888 DIV 2 Tail Gas Analyzer. Data
herein has been veried and validated and is believed adequate for the intended use of this instrument. If the instrument or procedures
are used for purposes over and above the capabilities specied herein, conrmation of their validity and suitability should be obtained;
otherwise, AMETEK does not guarantee results and assumes no obligation or liability. This publication is not a license to operate under, or
a recommendation to infringe upon, any process patents.
OFFICES
USA - Delaware
455 Corporate Blvd., Newark DE 19702
Tel: [phone]
Fax: [phone]
USA - Pennsylvania
150 Freeport Road, Pittsburgh PA 15238
Tel: [phone]
Fax: [phone]
CANADA - Alberta
2876 Sunridge Way N.E., Calgary, AB T1Y 7H9
Tel: [phone]
Fax: [phone]
WORLDWIDE SALES AND SERVICE LOCATIONS
USA - Texas
Tel: [phone], Fax: [phone]
CHINA
Beijing / Tel: [phone], Fax: [phone]
Chengdu / Tel: [phone], Fax: [phone]
Shanghai / Tel: [phone], Fax: [phone]
FRANCE
Tel: [phone], Fax: [phone]
GERMANY
Tel: [phone], Fax: [phone]
MIDDLE EAST - Dubai
Tel: [phone], Fax: [phone]
SINGAPORE
Tel: [phone], Fax: [phone]
www.ametekpi.com

Contents |3
Contents
Safety Notes .......................................................................................................... 7
Grounding..............................................................................................................7
Important Safety Information ................................................................................. 8
Storage Information ............................................................................................... 9
Warning Labels.................................................................................................... 10
Special Warnings and Information....................................................................... 15
Warranty and Claims ........................................................................................... 16
CHAPTER 1 Overview
Model 888 Tail Gas Analyzer ..............................................................................1-1
Electronics Enclosure...................................................................................1-2
Photometer...................................................................................................1-2
Xenon Lamp Assembly ................................................................................1-3
Detector Assembly .......................................................................................1-3
Lamp & Detector Mounting ..........................................................................1-3
User Interface/Host Display .........................................................................1-4
Sensor Board ...............................................................................................1-4
Sample Conditioning (Oven) Enclosure.......................................................1-4
Flow Diagrams .............................................................................................1-5
Light Tube/Mirror Block Assembly................................................................1-6
Demister.......................................................................................................1-6
Sample Cell..................................................................................................1-6
Steam Blowback Valve.................................................................................1-8
Heat Exchangers..........................................................................................1-8
Customer Connections Enclosure................................................................1-9
Customer Drawing Package ......................................................................1-10
Operation..........................................................................................................1-10
Timing Sequence.............................................................................................. 1-11
Sample Flow .............................................................................................. 1-11
CHAPTER 2 Specications
Model 888 Tail Gas Analyzer ..............................................................................2-1
CHAPTER 3 Installation and Start-Up
Prior to Installation..............................................................................................3-1
Analyzer Site Preparation ............................................................................3-2
Unpacking and Inspection............................................................................3-2
Space Requirements....................................................................................3-2
Installation Guidelines ........................................................................................3-4
Sample Tap Preparation...............................................................................3-5
Installation Procedure.........................................................................................3-6
Installing the Probe ......................................................................................3-7
Installing the Demister................................................................................ 3-11
Electrical Connections ...............................................................................3-13
System Start-Up and Operation .......................................................................3-15

4 | Model 888 Tail Gas Analyzer Class I, Division 2
Leak Checking ...........................................................................................3-15
System Operation.............................................................................................3-16
Analyzer Security - Passwords.........................................................................3-16
Starting Normal Operation .........................................................................3-16
Setting the Sample Gas Flow ..............................................................3-18
Analyzer Timing..........................................................................................3-20
Normal Timing Sequence ....................................................................3-21
Calibration Span Adjustment ............................................................................3-23
Calibration Procedure ................................................................................3-23
Analyzer Troubleshooting and Maintenance ....................................................3-26
Sample System Leakage Test....................................................................3-28
CHAPTER 4 Controller / User Interface
Refer to 883056904 User Interface Manual for details on the AMEVision interface
Passwords ..........................................................................................................4-1
CHAPTER 5 Alarms
Alarm Relays ......................................................................................................5-1
Alarm Conditions and Responses ......................................................................5-3
CHAPTER 6 Troubleshooting
Diagnostic Functions ..........................................................................................6-1
Problems and Possible Causes..........................................................................6-2
Oven/Cell Temperature Not Reaching Setpoint ...........................................6-2
Demister Temperature Not Reaching Setpoint.............................................6-2
Low Light Conditions....................................................................................6-3
Cleaning the Optical Surface.................................................................6-4
Check the Optical Alignment .................................................................6-4
CHAPTER 7 Parts Replacement
Part Numbers ....................................................................................................7-2
Parts Drawings ...................................................................................................7-3
APPENDIX A Wiring Diagrams
APPENDIX B H2S and SO2Calculations
Concentration Measurement ............................................................................. B-1
Absorbance Calculation .............................................................................. B-1
APPENDIX C Analyzer Timing
Timing States / Periods...................................................................................... C-1
Period 1 – Special Flush ............................................................................. C-1
Period 2 – Flush and Zero........................................................................... C-1
Period 3 – Sample Flush............................................................................. C-2
Period 4 – Measure..................................................................................... C-2
Zero and Photo-Span Calibration ......................................................... C-2
Operation Sequences........................................................................... C-3

Contents |5
Period 5 – Flush and Zero........................................................................... C-3
Period 6 – Track Zero.................................................................................. C-3
Period 7– Photo-Span Calibration............................................................... C-3
Period 8 – Track Photo-Span Calibration.................................................... C-4
Steam Blowback................................................................................... C-4
Period 9 – Pre-Steam Flush........................................................................ C-4
Period 10 – Steam Blowback...................................................................... C-4
Period 11 – Post Steam Flush..................................................................... C-4
Special Periods.................................................................................................. C-5
Period 12 – Continuous Flush..................................................................... C-5
Period 13– Continuous Hold ....................................................................... C-5
Period 14 – Continuous Sample ................................................................. C-5
APPENDIX D Parameter IDs / Modbus Addresses
APPENDIX E Alarm Codes

6 | Model 888 Tail Gas Analyzer Class I, Division 2
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Contents |7
About This Document
This document describes the user instructions for the safe operation of the
Model 888 Analyzer intended for use in Class I, Division 2 areas.
The procedures and information discussed in this document are the pro-
cedures to install, operate, and perform maintenance on the Model 888
Analyzer including all relevant safety warnings and cautions to ensure
the safety of personnel and the analyzer in Class I, Division 2 locations.
Safety Notes
Warnings, cautions, and notes contained in this document and in the User
Manual emphasize critical instructions as follows:
An operating procedure which, if not strictly observed, may result in
personal injury or environmental contamination.
An operating procedure which, if not strictly observed, may result in
damage to the equipment.
Important information that should not be overlooked.
Grounding
Instrument grounding is mandatory. Performance specifications and
safety protection are void if instrument is operated from an improp-
erly grounded power source.
Verify ground continuity of all equipment before applying power.
!
WARNING
!
CAUTION
!
WARNING

8 | Model 888 Tail Gas Analyzer Class I, Division 2
Important Safety Information
Before working on the analyzer, read and understand the following
Notes, Warnings, and Cautions, regarding safety and other required infor-
mation.
Additional Notes, Warnings, and Cautions included in individual proce-
dures in this manual indicate special conditions to consider during instal-
lation, before opening the analyzer covers or doors, and while working on
the analyzer.
High voltages are present in the analyzer housings. Always discon-
nect power and/or external power sources to the analyzer before open-
ing any covers or doors on the analyzer to check or perform mainte-
nance on any components within the enclosures.
If it is necessary to open the analyzer’s covers or doors while the cir-
cuits are live, first monitor the area for flammable gases and proceed
only when the area is safe.
When the Electronics Enclosure and/or other enclosures are open, take
appropriate precautions to avoid electrical shock. Hazardous voltages
are present inside.
All electrical connections, adjustments, or servicing of the analyzer
should be performed only by properly trained and qualified personnel.
All electrical connections, materials, and methods (plus all safety
standards and procedures) must be made in compliance with local
wiring regulations and electrical code for the hazardous area, as speci-
fied by the Owner Company, local electrical-inspection authority, and
National/EU regulations.
Follow appropriate regulatory and/or company procedures to lock out
the analyzer while working on the analyzer electronics.
Verify ground continuity of all equipment before applying power.
For electrical shock protection, the analyzer must be operated from
a grounded power source that has a securely connected protective
ground contact.
!
WARNING
!
WARNING
!
WARNING

Contents |9
The glass Xenon Flash Lamp is under high internal pressure which
could result in flying glass fragments if ruptured. Handle the tube
with care to avoid dropping it, subjecting it to impacts, applying
excessive force to it, or scratching it.
While handling a flash lamp, always wear protective devices (face
mask, clothing) to prevent possible injury, especially to hand and face
areas.
Before working on the sample system, confirm that the system has
been purged with zero fluid and is isolated (blocked in) from the pro-
cess.
The analyzer oven enclosure and components inside the analyzer oven
are hot; always wear protective devices to avoid burning yourself.
Check the sample probe installation. Ensure that all connections are
tight and there are no leaks before opening the sample inlet and return
valves.
The sample gas contains highly toxic and corrosive substances.
Proper personal protective equipment including fresh air breathing
apparatus, eye protection, and skin protection MUST BE worn when
installing the sample tap and/or opening the main oven chamber for
inspection or maintenance.
The sample gas contains highly toxic and corrosive substances. Ana-
lyzed sample must be returned to the process or vented to a safe area.
Storage Information
Humidity may damage the installed Optical filters. Any such dam-
age is not covered by warranty. Please consult Ametek customer
service or your local representative for service advice.
!
WARNING
!
WARNING
!
WARNING
!
WARNING
!
WARNING

10 | Model 888 Tail Gas Analyzer Class I, Division 2
Warning Labels
These symbols may appear on the instrument to alert you of existing
conditions.
PROTECTIVE CONDUCTOR TERMINAL
(BORNIER DE L’ECRAN DE PROTECTION)
Schutzerde
CAUTION - Risk of electric shock
(ATTENTION-RISQUE DE DÉCHARGE ÉLECTRIQUE)
Achtung - Hochspannung Lebensgefahr
CAUTION - Refer to accompanying documents
(ATTENTION-SE RÉFERER AUX DOCUMENTS JOINTS)
Achtung (Beachten Sie beiliegende Dokumente)
CAUTION - Hot Surface
(ATTENTION-SURFACE CHAUDE)
Achtung - Heiße Oberäche
Environmental Information (WEEE)
This AMETEK product contains materials that can be reclaimed and recycled. In some
cases the product may contain materials known to be hazardous to the environment
or human health. In order to prevent the release of harmful substances into the
environment and to conserve our natural resources, AMETEK recommends that you
arrange to recycle this product when it reaches its “end of life.”
Waste Electrical and Electronic Equipment (WEEE) should never be disposed of in a
municipal waste system (residential trash). The Wheelie Bin marking on this product is
a reminder to dispose of the product properly after it has completed its useful life and
been removed from service. Metals, plastics and other components are recyclable and
you can do your part by one of the following these steps:
• When the equipment is ready to be disposed of, take it to your
local or regional waste collection administration for recycling.
• In some cases, your “end-of-life” product may be traded in for
credit towards the purchase of new AMETEK instruments. Con-
tact your dealer to see if this program is available in your area.
• If you need further assistance in recycling your AMETEK product,
contact our office listed in the front of the instruction manual.
!
CAUTION

Contents |11
Electromagnetic Compatibility (EMC)
Read and follow the recommendations in this section to avoid perfor-
mance variations or damage to the internal circuits of this equipment
when installed in harsh electrical environments.
The various congurations of the Model 888 should not produce, or fall victim to, elec-
tromagnetic disturbances as specied in the European Union’s EMC Directive. Strict
compliance to the EMC Directive requires that certain installation techniques and wiring
practices are used to prevent or minimize erratic behavior of the Analyzer or its electronic
neighbors. Below are examples of the techniques and wiring practices to be followed.
In meeting the EMC requirements , the various Analyzer congurations described in this
manual rely heavily on the use of metallic shielded cables used to connect to the custom-
er’s equipment and power. Foil and braid shielded I/O and DC power cables are recom-
mended for use in otherwise unprotected situations. In addition, hard conduit, exible
conduit, and armor around non-shielded wiring also provides excellent control of radio
frequency disturbances. However, use of these shielding techniques is effective only
when the shielding element is connected to the equipment chassis/earth ground at both
ends of the cable run. This may cause ground loop problems in some cases. These should
be treated on a case-by-case basis. Disconnecting one shield ground may not provide suf-
cient protection depending on the electronic environment. Connecting one shield ground
via a 0.1 microfarad ceramic capacitor is a technique allowing high frequency shield
bonding while avoiding the AC-ground metal connection. In the case of shielded cables
the drain wire or braid connection must be kept short. A two-inch connection distance
between the shield’s end and the nearest grounded chassis point, ground bar or terminal
is highly recommended. An even greater degree of shield performance can be achieved
by using metallic glands for shielded cable entry into metal enclosures. Expose enough of
the braid/foil/drain where it passes through the gland so that the shield materials can be
wrapped backwards onto the cable jacket and captured inside the gland, and tightened up
against the metal interior.
Inductive loads connected to the low voltage “Alarm Contacts” are not recommended.
However, if this becomes a necessity, adhere to proper techniques and wiring practices.
Install an appropriate transient voltage suppression device (low voltage MOV, “Tran-
szorb,” or R/C) as close as possible to the inductive device to reduce the generation of
transients. Do not run this type of signal wiring along with other I/O or DC in the same
shielded cable. Inductive load wiring must be separated from other circuits in conduit by
using an additional cable shield on the offending cable.
In general, for optimum protection against high frequency transients and other distur-
bances, do not allow installation of this Analyzer where its unshielded I/O and DC cir-
cuits are physically mixed with AC mains or any other circuit that could induce transients
into the Analyzer or the overall system. Examples of electrical events and devices known
for generation of harmful electromagnetic disturbances include motors, capacitor bank
switching, storm related transients, RF welding equipment, static, and walkie-talkies.
!
CAUTION

12 | Model 888 Tail Gas Analyzer Class I, Division 2
FCC Verication Statement (USA)
This device complies with Part 15 of the FCC rules. Operation is subject to
the following two conditions: (1) this device may not cause harmful inter-
ference, and (2) this device must accept any interference received, includ-
ing interference that may cause undesired operation.
This equipment has been tested and found to comply with the limits
for a Class A digital device, pursuant to Part 15 of the FCC Rules.
These limits are designed to provide reasonable protection against
harmful interference when the equipment is operated in a commercial
environment. This equipment generates, uses, and can radiate radio
frequency energy and, if not installed and used in accordance with the
instruction manual, may cause harmful interference to radio commu-
nications. Operation of this equipment in a residential area is likely to
cause harmful interference, in which case the user will be required to
correct the interference at his own expense.
ICES-003 (Canada)
This Class (A) digital apparatus complies with Canadian ICES-003.
Cet appareil numerique de la classe (A) est conforme a la norme NMB-003 du
Canada.
Classied, Hazardous Area Protection
Components and Functions
This version of the Model 888 is designed to be used in Class I, Division
2 classified hazardous areas and complies with those requirements for
electrical equipment. The redundant heater control and enclosure designs
assure that the system will not ignite surrounding gases. For this reason,
any repairs must not bypass these safety considerations and must use
only recommended components.
The electronics enclosure should not be opened unless the area is known
to be safe and is being continuously monitored (See Combustible Gas De-
tection protection techniques in NFPA70 article 500 and 505).
The analyzer must be installed and operated in accordance with this in-
struction manual

Contents |13
Working with the electronics enclosure in an open position is typically
done only during installation, start-up (and verification), and certain
troubleshooting and maintenance procedures. In these cases, appropriate
safety conditions must have been met, per company policy.
The analyzer may only be energized with permission of the works
manager or his proxy. Permission may only be given when it has been
determined that an explosive atmosphere is not present or when the
necessary protective measures against explosion hazards have been
taken (“hot permit”) during the time that the system is energized.
The analyzer enclosure may not be opened when energized if an explo-
sive atmosphere is present.
!
WARNING

14 | Model 888 Tail Gas Analyzer Class I, Division 2
Special Warnings and Information
For Use of this Equipment in Class I, Division 2 Hazardous Locations
This equipment is designed to meet requirements for Class I, Division 2,
Groups ABCD or Non-Hazardous areas only.
Explosion Hazard - Substitution of components may impair
suitability for Class I, Division 2.
AVERTISSEMENT - RISQUE D’EXPLOSION - LA SUBSTITU-
TION DE COMPOSANT PEUT RENDRE CE MATERIEL IN-
ACCEPTABLE POUR LES EMPLACEMENTS DE CLASSE 1,
DIVISION 2.
Explosion Hazard - Do not disconnect equipment unless
power has been switched off or the area is known to be non-
hazardous.
AVERTISSEMENT - RISQUE D’EXPLOSION - AVANT DE
DECONNECTER L’EQUIPEMENT, COUPEZ LE COURANT OU
VOUS ASSUREZ VOUS QUE L’EMPLACEMENT EST DESIGNE
NON DANGEREUX.
All input and output wiring must be in accordance with Class I, Di-
vision 2 wiring methods and in accordance with the authority having
jurisdiction.
Exposure to some chemicals may degrade the sealing properties of
materials used in the following devices: All Relays.
!
WARNING
!
WARNING
!
CAUTION
!
WARNING

Contents |15
Warranty and Claims
We warrant that any equipment of our own manufacture or manufactured for us pur-
suant to our specifications which shall not be, at the time of shipment thereof by or for
us, free from defects in material or workmanship under normal use and service, will be
repaired or replaced (at our option) by us free of charge, provided that written notice
of such defect is received by us within twelve (12) months from date of shipment of
portable analyzers or within eighteen (18) months from date of shipment or twelve (12)
months from date of installation of permanent equipment, whichever period is shorter.
All equipment requiring repair or replacement under the warranty shall be returned to
us at our factory, or at such other location as we may designate after obtaining a Re-
turned Material Authorization (RMA) number, transportation prepaid. Such returned
equipment shall be examined by us and if it is found to be defective as a result of defec-
tive materials or workmanship, it shall be repaired or replaced as aforesaid. Our obliga-
tion does not include the cost of furnishing any labor in connection with the installation
of such repaired or replaced equipment or parts thereof, nor does it include the respon-
sibility or cost of transportation. In addition, instead of repairing or replacing the equip-
ment returned to us as aforesaid, we may, at our option, take back the defective equip-
ment, and refund in full settlement the purchase price thereof paid by Buyer.
Process photometric analyzers, process moisture analyzers, and sampling systems are
warranted to perform the intended measurement, only in the event that the customer
has supplied, and AMETEK has accepted, valid sample stream composition data, process
conditions, and electrical area classification prior to order acknowledgment. The pho-
tometric light sources are warranted for ninety (90) days from date of shipment. Resale
items warranty is limited to the transferable portion of the original equipment manufac-
turer’s warranty to AMETEK. If you are returning equipment from outside the United
State, a statement should appear on the documentation accompanying the equipment
being returned declaring that the goods being returned for repair are American goods,
the name of the firm who purchased the goods, and the shipment date.
The warranty shall not apply to any equipment (or part thereof) which has been tam-
pered with or altered after leaving our control or which has been replaced by anyone
except us, or which has been subject to misuse, neglect, abuse or improper use. Misuse
or abuse of the equipment, or any part thereof, shall be construed to include, but shall
not be limited to, damage by negligence, accident, fire or force of the elements. Improper
use or misapplications shall be construed to include improper or inadequate protection
against shock, vibration, high or low temperature, overpressure, excess voltage and the
like, or operating the equipment with or in a corrosive, explosive or combustible me-
dium, unless the equipment is specifically designed for such service, or exposure to any
other service or environment of greater severity than that for which the equipment was
designed.
The warranty does not apply to used or secondhand equipment nor extend to anyone
other than the original purchaser from us.
THIS WARRANTY IS GIVEN AND ACCEPTED IN LIEU OF ALL OTHER WARRANTIES,
WHETHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION AND WARRANTIES
OF FITNESS OR OF MERCHANTABILITY OTHER THAN AS EXPRESSLY SET FORTH HEREIN,
AND OF ALL OTHER OBLIGATIONS OR LIABILITIES ON OUR PART. IN NO EVENT SHALL
WE BE LIABLE UNDER THIS WARRANTY OR ANY OTHER PROVISION OF THIS AGREE-
MENT FOR ANY ANTICIPATED OR LOST PROFITS, INCIDENTAL DAMAGES, CONSEQUEN-
TIAL DAMAGES, TIME CHANGES OR ANY OTHER LOSSES INCURRED BY THE ORIGINAL
PURCHASER OR ANY THIRD PARTY IN CONNECTION WITH THE PURCHASE, INSTAL-

16 | Model 888 Tail Gas Analyzer Class I, Division 2
LATION, REPAIR OR OPERATION OF EQUIPMENT, OR ANY PART THEREOF COVERED BY
THIS WARRANTY OR OTHERWISE. WE MAKE NO WARRANTY, EXPRESS OR IMPLIED, IN-
CLUDING WITHOUT LIMITATION ANY WARRANTIES OF FITNESS OR OF MERCHANTABIL-
ITY, AS TO ANY OTHER MANUFACTURER’S EQUIPMENT, WHETHER SOLD SEPARATELY OR
IN CONJUNCTION WITH EQUIPMENT OF OUR MANUFACTURE. WE DO NOT AUTHORIZE
ANY REPRESENTATIVE OR OTHER PERSON TO ASSUME FOR US ANY LIABILITY IN CON-
NECTION WITH EQUIPMENT, OR ANY PART THEREOF, COVERED BY THIS WARRANTY.

Overview |1-1
OVERVIEW
Model 888 Tail Gas Analyzer
The AMETEK Model 888 Tail Gas Analyzer uses photometric analysis to
continuously monitor hydrogen sulde, H2S, and sulfur dioxide, SO2, pres-
ent in the tail gas stream of a Claus plant.
The analyzer consists of three enclosures (Figure 1-1): an electronics
enclosure; a temperature-controlled, flange-mounted, sample condition-
ing enclosure; and a signal disconnect enclosure. These enclosures are
assembled onto a rigid mounting panel for support and the full assembly
is installed directly on a pipeline. The analyzer is designed for outdoor,
hazardous area installations.
Maifold
Air
Inlet
Utility Gas
Inlet
Steam Blowback
Inlet
(optional)
SIDE VIEW
N. A./Divison 2
Electronics Enclosure
Display
Customer Connections
Enclosure
Keypad
Probe Removal Panel
FRONT VIEW
N.A./Division 2
Demister Vent
Pipe Flange
Oven Enclosure

1-2 | Model 888 Tail Gas Analyzer Class I, Division 2
Electronics Enclosure
Figure 1-2. Electronics Enclosure
Photometer
This analyzer uses a photometer to monitor the concentration of H2S and
SO2in a tail gas sample. A photometer is composed four main compo-
nents: (1) a source of EM radiation (or “light”) in the desired wavelength
region; (2) a measuring cell with windows capable of transmitting light in
the desired wavelength region and compatible with the sample composi-
tion; (3) a wavelength selection device to isolate the desired wavelength
region; and (4) a detector (or sensor) that is sensitive to the wavelength
region.
In this analyzer, the photometer spans from the electronics enclosure
to sample conditioning enclosure. The electronics enclosure houses the
source and detector assemblies. The sample conditioning enclosure
houses the light tube, mirror-block, and sample cell assemblies. All of the
photometer components are rigidly connected for optical stability.
B
A
4
PROPORTIONAL VALVE
HOST DISPLAY PCB
DETECTOR ASSEMBLY
AC/DC CONVERTER PCB
LINE FILTER
24 VOLT POWER SUPPLY
3
SENSOR PCB
FLASH LAMP POWER SUPPLY
4
3
2
MANIFOLD ASSEMBLY FLASH LAMP
PRESSURE TRANSDUCER
B
HEATER RELAY
A
N/A
2

Overview |1-3
Xenon Lamp Assembly
The source module consists of a high quality 3 mm arc xenon flash lamp,
0.1 uF close-coupled capacitor, and trigger electronics (with 50 Hz flash
rate). The close-coupled capacitor and trigger electronics are potted inside
a metal enclosure. The xenon lamp assembly is powered from the Xenon
Lamp Power Supply PCB.
Detector Assembly
Figure 1-3. Detector
The detector assembly consists of focusing optics, three beam splitters,
one front surface mirror, four band pass filters for wavelength selection
(centered at 232, 254, 280, and 400 nm), four silicon photodiodes, and
electronics. Upon exiting the sample cell, the light re-enters the electronics
and is optically conditioned into the detector assembly. The beam split-
ters and mirror divides the light through the four band pass filters (wave-
length selection) before reaching the photodiodes. The band pass filters
are temperature controlled for improved performance. The photodiodes
are soldered to the Detector PCB. The Detector PCB performs the signal
acquisition and integration. The signal information is then sent to the Sen-
sor PCB.
Lamp & Detector Mounting
The Xenon lamp and detector mounting assemblies are attached to an
alignment plate. The Xenon lamp mount contains a UV-grade fused silica,
plano-convex collimating lens. Repeatable installation and alignment of
the lamp and detector assemblies is achieved by using two-point keyed
connections. Both assemblies are secured using threaded retainers that
can be tightened by hand.

1-4 | Model 888 Tail Gas Analyzer Class I, Division 2
User Interface/Host Display
The local user interface is composed of an LCD color display and a stain-
less steel piezoelectric keypad. The keypad is suitable for use with a
gloved hand. The user interface allows the user to set the configuration,
test the functionality, and trouble-shoot any problems. The user interface
is powered by the host display board. In addition to enabling the local in-
terface, the host display board also allows for remote connectivity through
Ethernet and Modbus communications.
Sensor Board
The sensor board controls the main operations of the analyzer. These
operations include sample measurement, signal processing, calculations,
monitoring of temperatures and pressures, and providing analog and
relay outputs.
Sample Conditioning (Oven) Enclosure
Demister
Low Pressure
Operator
Cell Isolation/Steam
Blowback
Aspirator
Flange RTD
Zero Flush Heat
Exchanger
Aspirator Heat Exchanger
Sample Cell
Heater
Oven Enclosure
Figure 1-4. Oven Enclosure (interior)