Thermo 48i User manual

Model 48i
Instruction Manual
Gas Filter Correlation CO Analyzer
Part number 101891-00
8Apr2005

© 2005 Thermo Electron Corporation. All rights reserved.
“Analyze. Detect. Measure. Control” is a trademark of Thermo Electron Corporation. All other product names and
logos are the property of their respective owner.
Specifications, terms and pricing are subject to change. Not all products are available in all countries. Please consult
your local sales representative for details.

Thermo Electron Corporation Model 48iInstruction Manual iii
Contents
Chapter 1 Introduction...................................................................................... 1-1
Principle of Operation ............................................................ 1-2
Specifications .......................................................................... 1-3
Chapter 2 Installation ....................................................................................... 2-1
Lifting..................................................................................... 2-1
Unpacking and Inspection ...................................................... 2-1
Setup Procedure...................................................................... 2-3
Startup .................................................................................... 2-5
Chapter 3 Operation .......................................................................................... 3-1
Display.................................................................................... 3-2
Pushbuttons............................................................................ 3-3
Soft Keys.............................................................................. 3-4
Software Overview .................................................................. 3-4
Power-Up Screen ................................................................. 3-6
Run Screen........................................................................... 3-6
Main Menu.......................................................................... 3-7
Range Menu ........................................................................... 3-8
Single Range Mode .............................................................. 3-9
Dual Range Mode.............................................................. 3-10
Autorange Mode ................................................................ 3-11
Gas Units........................................................................... 3-14
CO Range.......................................................................... 3-15
Set Custom Ranges ............................................................ 3-17
Averaging Time..................................................................... 3-18
Calibration Factors Menu ..................................................... 3-19
CO Background Correction............................................... 3-20
CO Span Coefficients ........................................................ 3-21
Calibration Menu ................................................................. 3-22
Calibrate CO Background.................................................. 3-23
Calibrate CO Coefficient ................................................... 3-24
Zero/Span Check Menu..................................................... 3-25

Contents
iv Model 48iInstruction Manual Thermo Electron Corporation
Instrument Controls Menu ................................................... 3-29
Datalogging Settings .......................................................... 3-30
Communication Settings.................................................... 3-41
I/O Configuration.............................................................. 3-53
Temperature Compensation............................................... 3-71
Pressure Compensation ...................................................... 3-72
Screen Contrast.................................................................. 3-73
Service Mode ..................................................................... 3-74
Date/Time ......................................................................... 3-74
Diagnostics Menu ................................................................. 3-75
Program Version ................................................................ 3-76
Voltages ............................................................................. 3-77
Temperatures ..................................................................... 3-79
Pressure.............................................................................. 3-80
Flow................................................................................... 3-80
Sample/Reference Ratio ..................................................... 3-81
AGC Intensity.................................................................... 3-81
Motor Speed ...................................................................... 3-82
Analog Input Readings....................................................... 3-82
Analog Input Voltages........................................................ 3-83
Digital Inputs..................................................................... 3-84
Relay States ........................................................................ 3-84
Test Analog Outputs.......................................................... 3-85
Instrument Configuration.................................................. 3-86
Contact Information.......................................................... 3-87
Alarms Menu ........................................................................ 3-87
Internal Temperature ......................................................... 3-88
Bench Temperature............................................................ 3-90
Pressure.............................................................................. 3-91
Sample Flow ...................................................................... 3-93
Bias Voltage ....................................................................... 3-94
AGC Instensity .................................................................. 3-95
Motor Speed ...................................................................... 3-97
Zero and Span Check......................................................... 3-97
Zero and Span Auto Calibration ........................................ 3-99
Concentration.................................................................... 3-99
Service Menu ...................................................................... 3-101
Single/Dual/Auto Select................................................... 3-102
Pressure Calibration ......................................................... 3-103
Flow Calibration .............................................................. 3-106
Initial S/R Ratio............................................................... 3-109
Multi-point Calibration ................................................... 3-110
Preamp Board Calibration................................................ 3-113
Temperature Calibration.................................................. 3-114

Contents
Thermo Electron Corporation Model 48iInstruction Manual v
Analog Output Calibration ..............................................3-114
Analog Input Calibration .................................................3-117
Display Pixel Test ............................................................3-120
Restore User Defaults.......................................................3-121
Password .............................................................................3-121
Lock Instrument ..............................................................3-122
Change Password .............................................................3-122
Remove Password.............................................................3-123
Enter Password.................................................................3-124
Chapter 4 Calibration........................................................................................4-1
Equipment Required...............................................................4-1
CO Concentration Standard................................................4-1
Zero Air Generator ..............................................................4-1
Flow Meter(s) and Controller(s)...........................................4-2
Pressure Regulator for CO Standard Cylinder......................4-3
Mixing Chamber..................................................................4-3
Output Manifold .................................................................4-3
Pre-Calibration .......................................................................4-3
Calibration..............................................................................4-3
Connect the Instrument.......................................................4-3
Zero Adjust..........................................................................4-4
Span Adjust..........................................................................4-5
Additional Concentration Standards ....................................4-6
Calibration Curve ................................................................4-6
Calibration Frequency..........................................................4-6
Periodic Zero and Span Checks...............................................4-6
References ...............................................................................4-7
HI and LO Multi-Point Calibration .......................................4-7
Default Coefficients .............................................................4-8
Cal Point 1, 2, and 3 Adjust.................................................4-8
Chapter 5 Preventive Maintenance ...............................................................5-1
Replacement Parts...................................................................5-1
Cleaning the Outside Case......................................................5-2
Cleaning the Optics ................................................................5-2
IR Source Replacement ...........................................................5-3
Fan Filter Inspection and Cleaning .........................................5-3
Leak Test and Pump Check Out.............................................5-4
External Leaks......................................................................5-4
Leaks Across the Optional Zero/Span and
Sample Solenoid Valves........................................................5-4
Pump Rebuilding....................................................................5-5

Contents
vi Model 48iInstruction Manual Thermo Electron Corporation
Chapter 6 Troubleshooting.............................................................................. 6-1
Safety Precautions ................................................................... 6-1
Troubleshooting Guides.......................................................... 6-1
Board-Level Connection Diagrams ......................................... 6-5
Connector Pin Descriptions.................................................... 6-7
Service Locations................................................................... 6-20
Chapter 7 Servicing...........................................................................................7-1
Safety Precautions ................................................................... 7-3
Firmware Updates................................................................... 7-3
Replacement Parts List............................................................ 7-4
Cable List................................................................................ 7-5
Lowering the Partition Panel................................................... 7-7
Fuse Replacement ................................................................... 7-8
Fan Replacement..................................................................... 7-9
IR Source Replacement ......................................................... 7-10
Filter Wheel Replacement ..................................................... 7-11
Chopper Motor Replacement................................................ 7-13
Optical Bench Replacement.................................................. 7-14
Optical Switch Replacement ................................................. 7-15
Bench Heater Assembly Replacement.................................... 7-16
Detector/Preamplifier Assembly Replacement....................... 7-17
Pump Replacement............................................................... 7-18
Pressure Transducer Replacement ......................................... 7-20
Pressure Transducer Calibration ........................................... 7-21
Flow Transducer Replacement .............................................. 7-23
Flow Transducer Calibration ................................................ 7-24
Capillary Cleaning or Replacement ....................................... 7-25
Optional Zero/Span and Sample Solenoid
Valve Replacement................................................................ 7-26
Analog Output Testing ......................................................... 7-27
Analog Output Adjustment................................................... 7-29
Ambient Temperature Calibration ........................................ 7-30
I/O Expansion Board (Optional) Replacement ..................... 7-31
Digital Output Board Replacement....................................... 7-33
Motherboard Replacement.................................................... 7-34
Measurement Interface Board Replacement .......................... 7-35
Front Panel Board Replacement............................................ 7-36
LCD Module Replacement ................................................... 7-37
Service Locations................................................................... 7-39

Contents
Thermo Electron Corporation Model 48iInstruction Manual vii
Chapter 8 System Description.........................................................................8-1
Hardware ................................................................................8-2
Optical Bench ......................................................................8-3
Band-pass Filter ...................................................................8-3
Bench Heater Board.............................................................8-3
Chopper Motor....................................................................8-3
Optical Pickup.....................................................................8-4
Gas Filter Wheel ..................................................................8-4
Infrared Source ....................................................................8-4
Pre-amplifier Assembly with IR Detector .............................8-4
Sample Flow Sensor .............................................................8-4
Pressure Transducer .............................................................8-4
Capillary ..............................................................................8-4
Pump ...................................................................................8-4
Purge Flow Switch (optional)...............................................8-4
Software..................................................................................8-5
Instrument Control..............................................................8-5
Monitoring Signals...............................................................8-5
Output Communication......................................................8-5
Electronics ..............................................................................8-7
Motherboard........................................................................8-7
Measurement Interface Board ..............................................8-8
Flow Sensor Assembly..........................................................8-8
Pressure Sensor Assembly .....................................................8-8
Bench Heater Board.............................................................8-9
Pre-amp Board Assembly .....................................................8-9
Digital Output Board...........................................................8-9
I/O Expansion Board (Optional) .........................................8-9
Front Panel Connector Board ..............................................8-9
I/O Components ..................................................................8-10
Analog Voltage Outputs.....................................................8-10
Analog Current Outputs (Optional) ..................................8-10
Analog Voltage Inputs (Optional)......................................8-11
Digital Relay Outputs ........................................................8-11
Digital Inputs.....................................................................8-11
Serial Ports.........................................................................8-11
RS-232 Connection ...........................................................8-12
RS-485 Connection ...........................................................8-13
Ethernet Connection..........................................................8-13
External Accessory Connector ............................................8-13
Chapter 9 Optional Equipment ........................................................................9-1
Internal Zero/Span Assembly ..................................................9-1
Internal Zero Air Scrubber ......................................................9-1

Contents
viii Model 48iInstruction Manual Thermo Electron Corporation
Filter Wheel Purge ..................................................................9-1
Calibration Note.................................................................. 9-2
Teflon Particulate Filter .......................................................... 9-3
I/O Expansion Board Assembly............................................... 9-3
Terminal Block and Cable Kits ............................................... 9-3
Mounting Options.................................................................. 9-4
Appendix A Warranty............................................................................................ A-1
Appendix B C-Link Protocol Commands............................................................ B-1
Instrument Identification Number..........................................B-2
Commands .............................................................................B-2
Measurements.........................................................................B-8
Alarms...................................................................................B-11
Diagnostics ...........................................................................B-15
Datalogging ..........................................................................B-16
Calibration............................................................................B-22
Keys/Display.........................................................................B-25
Measurement Configuration .................................................B-27
Hardware Configuration.......................................................B-30
Communications Configuration ...........................................B-32
I/O Configuration.................................................................B-36
Record Layout Definition .....................................................B-40
Format Specifier for ASCII Responses................................B-41
Format Specifier for Binary Responses ...............................B-41
Format Specifier for Front-Panel Layout ...........................B-41
Appendix C MODBUS Protocol ........................................................................... C-1
Serial Communication Parameters ..........................................C-2
TCP Communication Parameters ...........................................C-2
Application Data Unit Definition ...........................................C-2
Function Codes.......................................................................C-3
MODBUS Commands Supported..........................................C-8

Thermo Electron Corporation Model 48iInstruction Manual ix
About This Manual
This manual provides information about operating, maintaining, and
servicing the analyzer. It also contains important alerts to ensure safe
operation and prevent equipment damage. The manual is organized into the
following chapters and appendices to provide direct access to specific
operation and service information:
• Chapter 1 “Introduction” provides an overview of product features,
describes the principles of operation, and lists the specifications.
• Chapter 2 “Installation” describes how to unpack, setup, and startup the
analyzer.
• Chapter 3 “Operation” describes the front panel display, the front panel
pushbuttons, and the menu-driven software.
• Chapter 4 “Calibration” provides the procedures for calibrating the
analyzer and describes the required equipment.
• Chapter 5 “Preventive Maintenance” provides maintenance procedures
to ensure reliable and consistent instrument operation.
• Chapter 6 “Troubleshooting” presents guidelines for diagnosing analyzer
failures, isolating faults, and includes recommended actions for restoring
proper operation.
• Chapter 7 “Servicing” presents safety alerts for technicians working on
the analyzer, step-by-step instructions for repairing and replacing
components, and a replacement parts list. It also includes contact
information for product support and technical information.
• Chapter 8 “System Description” describes the function and location of
the system components, provides an overview of the software structure,
and includes a description of the system electronics and input/output
connections.
• Chapter 9 “Optional Equipment” describes the optional equipment that
can be used with this analyzer.
• Appendix A “Warranty” provides a copy of the warranty statement.

Preface
xModel 48iInstruction Manual Thermo Electron Corporation
• Appendix B “C-Link Protocol Commands” provides a description of the
C-Link protocol commands that can be used to remotely control an
analyzer using a host device such as a PC or a datalogger.
• Appendix C “MODBUS Protocol” provides a description of the
MODBUS Protocol Interface and is supported both over RS-232/485
(RTU protocol) as well as TCP/IP over Ethernet.
Safety Review the following safety information carefully before using the analyzer.
This manual provides specific information on how to operate the analyzer,
however if the analyzer is used in a manner not specified by the
manufacturer, the protection provided by the equipment may be impaired.
Safety and Equipment
Damage Alerts
This manual contains important information to alert you to potential safety
hazards and risks of equipment damage. Refer to the following types of
alerts you may see and the actual alerts that appear in this manual.
Safety and Equipment Damage Alert Descriptions
Alert Description
DANGER A hazard is present that will result in death or serious
personal injury if the warning is ignored. 
WARNING A hazard is present or an unsafe practice can result in
serious personal injury if the warning is ignored. 
CAUTION The hazard or unsafe practice could result in minor to
moderate personal injury if the warning is ignored. 
Equipment Damage The hazard or unsafe practice could result in property
damage if the warning is ignored. 

Preface
Thermo Electron Corporation Model 48iInstruction Manual xi
Where to Get Help Service is available from exclusive distributors worldwide. Contact one of
the phone numbers below for product support and technical information.
866-282-0430
508-520-0430
Safety and Equipment Damage Alerts in this Manual
Alert Description
WARNING If the equipment is operated in a manner not specified by
the manufacturer, the protection provided by the
equipment may be impaired. 
The service procedures in this manual are restricted to
qualified service personnel only. 
The Model 48iis supplied with a three-wire grounding
cord. Under no circumstances should this grounding
system be defeated. 
CAUTION If the LCD panel breaks, do not to let the liquid crystal
contact your skin or clothes. If the liquid crystal contacts
your skin or clothes, wash it off immediately using soap
and water. 
Equipment Damage Do not attempt to lift the analyzer by the cover or other
external fittings. 
Some internal components can be damaged by small
amounts of static electricity. A properly grounded
antistatic wrist strap must be worn while handling any
internal component. 
Handle all printed circuit boards by the edges only. 
Do not remove the panel or frame from the LCD module.

The LCD module polarizing plate is very fragile, handle it
carefully. 
Do not wipe the LCD module polarizing plate with a dry
cloth, it may easily scratch the plate. 
Do not use Ketonics solvent or aromatic solvent to clean
the LCD module, use a soft cloth moistened with a
naphtha cleaning solvent. 
Do not place the LCD module near organic solvents or
corrosive gases. 
Do not shake or jolt the LCD module. 

Preface
Thermo Electron Corporation Model 48iInstruction Manual xii

Thermo Electron Corporation 48iInstruction Manual 1-1
Chapter 1 Introduction
The Model 48iCO Analyzer measures CO concentration using Gas Filter
Correlation (GFC). The Model 48icombines proven detection technology,
easy to use menu-driven software, and advanced diagnostics to offer
unsurpassed flexibility and reliability. The Model 48ihas the following
features:
• 320 x 240 graphics display
• Menu-driven software
• Field programmable ranges
• User-selectable single/dual/auto range modes
• Multiple user-defined analog outputs
• Analog input options
• High sensitivity
• Fast response time
• Linearity through all ranges
• Highly specific to CO
• Self-aligning optics
• Automatic temperature and pressure compensation
• User-selectable digital input/output capabilities
• Standard communications features include RS232/485 and Ethernet
• C-Link, MODBUS, and streaming data protocols
For details of the analyzer’s principle of operation and product
specifications, see the following topics:

Introduction
Principle of Operation
1-2 48iInstruction Manual Thermo Electron Corporation
•“Principle of Operation” on page 1-2 describes the principles by which
your analyzer operates.
•“Specifications” on page 1-3 is a list of the analyzer’s performance
specifications.
Thermo Electron is pleased to supply this CO analyzer. We are committed
to the manufacture of instruments exhibiting high standards of quality,
performance, and workmanship. Service personnel are available for
assistance with any questions or problems that may arise in the use of this
analyzer. For more information on servicing, see Chapter 7 “Servicing”.
Principle of Operation The Model 48ioperates on the principle that carbon monoxide (CO)
absorbs infrared radiation at a wavelength of 4.6 microns. Because infrared
absorption is a non-linear measurement technique, it is necessary to
transform the basic analyzer signal into a linear output. The Model 48iuses
an internally stored calibration curve to accurately linearize the instrument
output over any range up to a concentration of 10,000 ppm.
The sample is drawn into the Model 48ithrough the sample bulkhead, as
shown in Figure 1-1. The sample flows through the optical bench.
Radiation from an infrared source is chopped and then passed through a gas
filter alternating between CO and N2. The radiation then passes through a
narrow bandpass interference filter and enters the optical bench where
absorption by the sample gas occurs. The infrared radiation then exits the
optical bench and falls on an infrared detector.
The CO gas filter acts to produce a reference beam which cannot be further
attenuated by CO in the sample cell. The N2side of the filter wheel is
transparent to the infrared radiation and therefore produces a measurement
beam which can be absorbed by CO in the cell. The chopped detector signal
is modulated by the alternation between the two gas filters with an
amplitude related to the concentration of CO in the sample cell. Other
gases do not cause modulation of the detector signal since they absorb the
reference and measure beams equally. Thus, the GFC system responds
specifically to CO.
The Model 48ioutputs the CO concentration to the front panel display, the
analog outputs, and also makes the data available over the serial or ethernet
connection.

Introduction
Specifications
Thermo Electron Corporation 48iInstruction Manual 1-3
Figure 1-1. Model 48iFlow Schematic
Specifications Table 1-1. Model 48iSpecifications
Preset ranges 0-1, 2, 5, 10, 20, 50, 100, 200, 500, 1000, 2000, 5000, 10000 (ppm
or mg/m3)
Custom ranges 0-1 to 10000 (ppm or mg/m3)
Zero roise 0.02 ppm RMS (30 second averaging time)
Lower detectable limit 0.04 ppm
Zero drift (24 hour) < 0.1 ppm
Span drift ±1% full-scale
Response time 60 seconds (30 second averaging time)
Linearity ±1% of full-scale ≤1000 ppm
±2.5% of full-scale >1000 ppm
Sample flow rate 1.0 LPM
Operating temperature 20–30 °C (may be safely operated over the range of 0–45 °C)*

Introduction
Specifications
1-4 48iInstruction Manual Thermo Electron Corporation
Power requirements 100 VAC @ 50/60 Hz
115 VAC @ 50/60 Hz
220–240 VAC @ 50/60 Hz
275 watts
Physical dimensions 16.75” (W) X 8.62” (H) X 23” (D)
Weight Approximately 49 lbs.
Analog outputs 6 voltage outputs; 0–100 mV, 1, 5, 10 V (User selectable), 5% of
full-scale over/under range, 12 bit resolution, user selectable for
measurement input
Digital outputs 1 power fail relay Form C, 10 digital relays Form A, user selectable
alarm output, relay logic, 100 mA @ 200 VDC
Digital inputs 16 digital inputs, user select programmable, TTL level, pulled high
Serial Ports 1 RS-232 or RS-485 with two connectors, baud rate 1200–115200,
data bits, parity, and stop bits, protocols: C-Link, MODBUS, and
streaming data (all user selectable)
Ethernet connection RJ45 connector for 10Mbs Ethernet connection, static or dynamic
TCP/IP addressing
*In non condensing environments. Performance specifications based on operation with 20–30 °C range.

Thermo Electron Corporation Model 48iInstruction Manual 2-1
Chapter 2 Installation
Installing the Model 48iincludes the following recommendations and
procedures:
•“Lifting” on page 2-1
•“Unpacking and Inspection” on page 2-1
•“Setup Procedure” on page 2-3
•“Startup” on page 2-5
Lifting When lifting the instrument, use procedure appropriate to lifting a heavy
object, such as, bending at the knees while keeping your back straight and
upright. Grasp the instrument at the bottom in the front and at the rear of
the unit. Although one person can lift the unit, it is desirable to have two
persons lifting, one by grasping the bottom in the front and the other by
grasping the bottom in the rear.
Unpacking and
Inspection
The Model 48iis shipped complete in one container. If there is obvious
damage to the shipping container when you receive the instrument, notify
the carrier immediately and hold for inspection. The carrier is responsible
for any damage incurred during shipment.
Use the following procedure to unpack and inspect the instrument.
1. Remove the instrument from the shipping container and set it on a table
or bench that allows easy access to both the front and rear.
2. Remove the cover to expose the internal components.
Equipment Damage Do not attempt to lift the instrument by the cover or
other external fittings. 

Installation
Unpacking and Inspection
2-2 Model 48iInstruction Manual Thermo Electron Corporation
3. Remove the packing material (Figure 2-1).
Figure 2-1. Remove the Packing Material
4. Remove the three shipping screws (Figure 2-2).
Figure 2-2. Remove the Shipping Screws
5. Check for possible damage during shipment.
Units without Optional I/O Board Units with Optional I/O Board
Remove Packing
Remove Packing
(2 pieces)
(2 pieces)
Shipping Screws (3)

Installation
Setup Procedure
Thermo Electron Corporation Model 48iInstruction Manual 2-3
6. Check that all connectors and circuit boards are firmly attached.
7. Re-install the cover.
Setup Procedure Use the following procedure to setup the instrument.
1. Connect the sample line to the SAMPLE bulkhead on the rear panel
(Figure 2-3). Ensure that the sample line is not contaminated by dirty,
wet, or incompatible materials. All tubing should be constructed of FEP
Teflon®, 316 stainless steel, borosilicate glass, or similar tubing with an
OD of 1/4-inch and a minimum ID of 1/8-inch. The length of the
tubing should be less than 10 feet.
Note Gas must be delivered to the instrument at atmospheric pressure. It
may be necessary to use an atmospheric bypass plumbing arrangement as
shown in Figure 2-4. 
2. Connect the EXHAUST bulkhead to a suitable vent. The exhaust line
should be 1/4-inch OD with a minimum ID of 1/8-inch. The length of
the exhaust line should be less than 10 feet. Verify that there is no
restriction in this line.
3. If the optional zero/span solenoid valves are installed, connect a source
of CO-free air to the ZERO bulkhead, and connect a source of CO
span gas to the SPAN bulkhead.
4. Connect a suitable recording device to the rear panel connector. See the
“Operation” chapter for more information about the rear panel
pin-outs.
5. Plug the instrument into an outlet of the appropriate voltage and
frequency.
WARNING The Model 48iis supplied with a three-wire grounding cord.
Under no circumstances should this grounding system be defeated. 

Installation
Setup Procedure
2-4 Model 48iInstruction Manual Thermo Electron Corporation
Figure 2-3. Model 48iRear Panel
Figure 2-4. Atmospheric Dump Bypass Plumbing
Instrument Bulkhead Vent to Exhaust Line
at Atmospheric Pressure
Input Gas Line