Teledyne 2000A-EU User Manual

Thermal Conductivity Analyzer

OPERATING INSTRUCTIONS FOR

Model 2000A-EU

Thermal Conductivity Analyzer

DANGER

HIGHLY TOXIC AND OR FLAMMABLE LIQUIDS OR GASES MAY BE PRESENT IN THIS MONITORING
SYSTEM.

PERSONAL PROTECTIVE EQUIPMENT MAY BE REQUIRED WHEN SERVICING THIS SYSTEM.
HAZARDOUS VOLTAGES EXIST ON CERTAIN COMPONENTS INTERNALLY WHICH MAY PERSIST

FOR A TIME EVEN AFTER THE POWER IS TURNED OFF AND DISCONNECTED.
ONLY AUTHORIZED PERSONNEL SHOULD CONDUCT MAINTENANCE AND/OR SERVICING. BEFORE

CONDUCTING ANY MAINTENANCE OR SERVICING CONSULT WITH AUTHORIZED SUPERVISOR/
MANAGER.

Teledyne Analytical Instruments

P/N M66182

07/22/05

ECO # 05-0131

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Model 2000A-EU

Copyright © 1999 Teledyne Analytical Instruments

All Rights Reserved. No part of this manual may be reproduced, transmitted, tran­scribed, stored in a retrieval system, or translated into any other language or computer
language in whole or in part, in any form or by any means, whether it be electronic,
mechanical, magnetic, optical, manual, or otherwise, without the prior written consent of
Teledyne Analytical Instruments, 16830 Chestnut Street, City of Industry, CA 91749-1580.

Warranty

This equipment is sold subject to the mutual agreement that it is warranted by us free
from defects of material and of construction, and that our liability shall be limited to
replacing or repairing at our factory (without charge, except for transportation), or at
customer plant at our option, any material or construction in which defects become
apparent within one year from the date of shipment, except in cases where quotations or
acknowledgements provide for a shorter period. Components manufactured by others bear
the warranty of their manufacturer. This warranty does not cover defects caused by wear,
accident, misuse, neglect or repairs other than those performed by Teledyne or an autho­rized service center. We assume no liability for direct or indirect damages of any kind and
the purchaser by the acceptance of the equipment will assume all liability for any damage
which may result from its use or misuse.

We reserve the right to employ any suitable material in the manufacture of our
apparatus, and to make any alterations in the dimensions, shape or weight of any parts, in
so far as such alterations do not adversely affect our warranty.

Important Notice

This instrument provides measurement readings to its user, and serves as a tool by
which valuable data can be gathered. The information provided by the instrument may
assist the user in eliminating potential hazards caused by his process; however, it is
essential that all personnel involved in the use of the instrument or its interface, with the
process being measured, be properly trained in the process itself, as well as all instrumenta­tion related to it.

The safety of personnel is ultimately the responsibility of those who control process
conditions. While this instrument may be able to provide early warning of imminent danger,
it has no control over process conditions, and it can be misused. In particular, any alarm or
control systems installed must be tested and understood, both as to how they operate and
as to how they can be defeated. Any safeguards required such as locks, labels, or redun­dancy, must be provided by the user or specifically requested of Teledyne at the time the
order is placed.

Therefore, the purchaser must be aware of the hazardous process conditions. The
purchaser is responsible for the training of personnel, for providing hazard warning
methods and instrumentation per the appropriate standards, and for ensuring that hazard
warning devices and instrumentation are maintained and operated properly.

Teledyne Analytical Instruments, the manufacturer of this instrument, cannot
accept responsibility for conditions beyond its knowledge and control. No statement
expressed or implied by this document or any information disseminated by the manufactur­er or its agents, is to be construed as a warranty of adequate safety control under the

user’s process conditions.

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Thermal Conductivity Analyzer

Specific Model Information

The instrument for which this manual was supplied may incorporate one or more
options not supplied in the standard instrument. Commonly available options are listed
below, with check boxes. Any that are incorporated in the instrument for which this
manual is supplied are indicated by a check mark in the box.

Instrument Serial Number: _______________________

Options Available with Order:

❑❑

❑ 2000A-C: Auto Calibration valves (zero/span) built-in gas selector panel

❑❑

and control valves are electronically controlled to provide
synchronization with the analyzer’s operations.

❑❑

❑ 2000A-G: Stainless steel cell block with nickel filaments and Stainless

❑❑

Steel fittings and tubing.

❑❑

❑ 2000A-H: Stainless steel cell block with gold filaments for corrosive gas

❑❑

streams and Stainless Steel fittings and tubing.

❑❑

❑ 2000A-K: 19" Rack Mount available with either one or two analyzers

❑❑

Control Units installed and ready to mount in a standard rack

❑❑

❑ 2000A-L: Gas selector panel consisting of sample/ref flow meters and

❑❑

control valves for metering input of sample/calibrations
support gases

❑❑

❑ 2000A-R: Sealed reference cell (application dependent, contact factory).

❑❑
❑❑

❑ 2000A-N: 220 VAC operation.

❑❑

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Model 2000A-EU

Model 2000A-EU complies with all of the requirements of the
Commonwealth of Europe (CE) for Radio Frequency Interference,
Electromagnetic Interference (RFI/EMI), and Low Voltage Directive
(LVD).

The following International Symbols are used throughout the In­struction Manual for your visual and immediate warnings and when
you have to attend CAUTION while operating the instrument:

STAND-BY, Instrument is on Stand-by,
but circuit is active

GROUND

Protective Earth

CAUTION, The operator needs to refer to the manual

for further information. Failure to do so may
compromise the safe operation of the equipment.

CAUTION, Risk of Electric Shock

D ANGER

COMBUSTIBLE GAS USAGE WARNING

This is a general purpose instrument designed for usage in a
nonhazardous area. It is the customer's responsibility to en­sure safety especially when combustible gases are being ana­lyzed since the potential of gas leaks always exist.

The customer should ensure that the principles of operating of
this equipment is well understood by the user. Misuse of this
product in any manner, tampering with its components, or
unauthorized substitution of any component may adversely
affect the safety of this instrument.

Since the use of this instrument is beyond the control of
Teledyne, no responsibility by Teledyne, its affiliates, and
agents for damage or injury from misuse or neglect of this
equipment is implied or assumed.

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Thermal Conductivity Analyzer

Table of Contents

1 Introduction

1.1 Overview........................................................................ 1-1

1.2 Typical Applications ....................................................... 1-2

1.3 Main Features of the Analyzer ....................................... 1-2

1.4 Model Designations ....................................................... 1-3

1.5 Front P anel (Operator Interface)..................................... 1-3

1.6 Recognizing Difference Between LCD & VFD............... 1-5

1.7 Rear Panel (Equipment Interface) .................................. 1-5

1.8 Gas Connections ........................................................... 1-7

2 Operational Theory

2.1 Introduction .................................................................... 2-1

2.2 Sensor Theory ............................................................... 2-1

2.2.1 Sensor Configuration............................................... 2-1

2.2.2 Calibration ............................................................... 2-2

2.2.3 Effects of Flowrate and Gas Density........................ 2-3

2.2.4 Measurement Results.............................................. 2-3

2.3 Electronics and Signal Processing ................................ 2-3

2.4 Temperature Control ...................................................... 2-5

3 Installation

3.1 Unpacking the Analyzer................................................. 3-1

3.2 Mounting the Analyzer ................................................... 3-1

3.3 Electrical Connections (Rear Panel).............................. 3-3

3.3.1 Primary Input Power............................................... 3-4

3.3.2 Primary Input Power............................................... 3-4

3.3.3 50-Pin Equipment Interface Connector .................. 3-4

3.3.3.1 Analog Outputs .............................................. 3-5

3.3.3.2 Alarm Relays ................................................. 3-6

3.3.3.3 Digital Remote Cal Inputs.............................. 3-7

3.3.3.4 Range ID Relays ........................................... 3-9

3.3.3.5 Network I/O .................................................... 3-9

3.3.3.6 Remote V alv e Connector ............................... 3-9

3.3.4 RS-232 Port ........................................................... 3-10

3.4 Gas Connections ........................................................... 3-11

3.4.1 Sample System Design .........................................3-13

3.4.2 Pressure and Flow Rate Regulation......................3-13

3.4.3 VENT Exhaust .......................................................3-14

3.4.4 SAMPLE Gas.........................................................3-14

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Model 2000A-EU

3.4.5 REFERENCE Gas ................................................ 3-15

3.4.6 ZERO Gas .............................................................3-15

3.4.7 SPAN Gas..............................................................3-15

3.5 Testing the System.........................................................3-16

3.6 Warm Up at Po w er Up....................................................3-16

4 Operation

4.1 Introduction .................................................................... 4-1

4.2 Using the Data Entry and Function Buttons ................... 4-1

4.3 The

4.3.1 Setting the Display................................................. 4-5

4.3.2 Setting up an Auto-Cal........................................... 4-5

4.3.3 Passw ord Protection.............................................. 4-6

4.3.3.1 Entering the Password................................... 4-7

4.3.3.2 Installing or Changing the Password ............. 4-7

4.3.4 Logging Out ........................................................... 4-9

4.3.5 System Self-Diagnostic Test .................................. 4-9

4.3.6 The Model Screen ................................................. 4-10

4.3.7 Checking Linearity with ALGORITHM ................... 4-10

4.4 The

4.4.1 Zero Cal ................................................................. 4-12

4.4.1.1 Auto Mode Zeroing ........................................ 4-12

4.4.1.2 Manual Mode Zeroing.................................... 4-13

4.4.1.3 Cell Failure .................................................... 4-14

4.4.2 Span Cal................................................................ 4-14

4.4.2.1 Auto Mode Spanning ..................................... 4-15

4.4.2.2 Manual Mode Spanning................................. 4-15

4.5 The

4.6 The

4.6.1 Manual (Select/Define Range) Screen .................. 4-19

4.6.2 Auto (Single Application) Screen........................... 4-19

4.6.3 Precautions............................................................ 4-21

4.7 The

4.8 Programming ................................................................. 4-22

4.8.1 The Set Range Screen .......................................... 4.23

4.8.2 The Curve Algorithm Screen ................................. 4-25

4.8.2.1 Checking the Linearization ............................ 4-25

4.8.2.2 Manual Mode Linearization ........................... 4-26

4.8.2.3 Auto Mode Linearization................................ 4-27

4.9 Special Function Setup.................................................. 4-28

4.9.1 Output Signal Reversal.......................................... 4.28

System

Zero

and

Alarms
Range

Analyze

Function ..................................................... 4-4

Span

Functions ....................................... 4-11

Function...................................................... 4-16

Function ...................................................... 4-18

Function.................................................... 4-22

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Thermal Conductivity Analyzer

4.9.2 Special - Inverting Output ...................................... 4-29

4.9.3 Special - Polarity Coding ....................................... 4.29

4.9.4 Special - Nonlinear Application Gain Preset.......... 4-29

Maintenance

5.1 Routine Maintenance..................................................... 5-1

5.2 System Self Diagnostic Test........................................... 5-1

5.3 VFD Display .................................................................. 5-2

5.4 Fuse Replacement ......................................................... 5-2

5.5 Major Internal Components............................................ 5-3

5.6 Cell, Heater, and/or Thermistor Replacement ................ 5-5

5.6.1 Removing the Cell Compartment........................... 5-5

5.6.2 Removing and Replacing the Cell Block ............... 5-6

5.6.3 Removing the Heater and/or Thermocouple .......... 5-7

5.7 Cleaning ........................................................................ 5-4

5.8 Phone Numbers............................................................. 5-5

Appendix

A-1 Specifications ................................................................ A-1

A-2 Recommended 2-Year Spare Parts List ......................... A-3

A-3 Drawing List................................................................... A-4

A-4 19-Inch Relay Rack Panel Mount................................... A-4

A-5 Calibration Procedure for TG Application........................... A-5

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Model 2000A-EU

viii

Thermal Conductivity Analyzer Introduction 1

Introduction

1.1 Overview

The Analytical Instruments Model 2000 Thermal Conductivity Ana­lyzer is a versatile microprocessor-based instrument for measuring a com­ponent gas in a background gas, or in a specific mixture of background
gases. 2000A-EU Analyzer complies with all of the requirements of the
Comonwealth of Europe (CE) for Radio Frequency Interference and Elec­tromagnetic Interfaces (RFI/EMI) protection. It compares the thermal
conductivity of a sample stream with that of a reference gas of known
composition. The 2000 can—

• measure the concentration of one gas in a mixture of two gases.

• measure the concentration of a gas in a specific mixture of
background gases.

• measure the purity of a sample stream containing a single
impurity or a mixture of impurities.

The standard 2000 is preprogrammed with automatic linearization
algorithms for a large number of gases and gas mixtures. The factory can
add to this data base for custom applications, or the sophisticated user can
add his own unique application.

This manual covers the Model 2000A-EU General Purpose flush­panel and rack-mount units only. These units are for indoor use in a
nonhazardous environment.

Many of the Model 2000 features covered in this manual are optional,
selected according to the customers specific application. Therefore, the user
will find much here that does not apply to his instrument. This is unavoid­able due to the number of possible combinations of features available. We
have endeavored to make the manual as usable and convenient as possible,
in light of this flexibility.

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1-1

1 Introduction Model 2000A-EU

1.2 Typical Applications

A few typical applications of the Model 2000 are:

• Power Generation

• Air liquefaction

• Chemical reaction monitoring

• Steel manufacturing and heat treating

• Petrochemical process control

• Quality assurance

• Refrigeration and storage

• Gas proportioning control.

1.3 Main Features of the Analyzer

The main features of the Model 2000 Thermal Conductivity Analyzer

include:

• Three independent, user definable, analysis ranges allow up to
three different gas applications with one concentration range
each, or up to three concentration ranges for a single gas appli­cation, or any combination.

• Special recalibration range for multiple applications. Recalibrat­ing one, recalibrates all.

• Automatic, independent linearization for each range.

• Auto Ranging allows analyzer to automatically select the proper
preset range for a given single application. Manual override
allows the user to lock onto a specific range of interest.

• RS-232 serial digital port for use with a computer or other
digital communications device.

• Two adjustable concentration alarms and a system failure alarm.

• Extensive self-diagnostic testing, at startup and on demand.

• A 2-line alphanumeric display screen, driven by microprocessor
electronics, that continuously prompts and informs the operator.

• High resolution, accurate indication of target or impurity gas
concentration from large, bright, meter readout. (0-9999 ppm
through 0-100 % depending on types of gas involved.)

1-2

• Standard, proven sensor cell design.

• Wide range of custom applications, ranges, and linearization.

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Thermal Conductivity Analyzer Introduction 1

• Microprocessor based electronics: 8-bit CMOS microprocessor
with 32 kB RAM and 128 kB ROM.

• Auto and remote calibration capabilities.

• CE Mark Certified.

• Four analog outputs: two for measurement (0–1 V dc and
Isolated 4–20 mA dc) and two for range identification.

• Compact and versatile design: Small footprint, yet internal
components are accessible.

1.4 Model Designations

The Model 2000A-EU is ordinarily custom programmed at the factory
to fit the customer’s application. Many parameters, including the number of
channels, the gas application, the materials specification of the sampling
system, and others, are options. The most common options, are covered in
this manual. See the Specific Model Information checklist in the front pages
of this manual for those that apply to your Model 2000A analyzer. Some
standard models that are not covered in this manual are listed here.

Models 2000B: NEMA-4, bulkhead mounted enclosure for general

purpose, nonhazardous environments.

Models 2010: Split architecture models using a sealed explosion-proof

enclosure for the Analysis Unit and a general purpose
remote Control Unit for installation in a safe area.

Models 2020: Both the analysis section and control unit are in a single

explosion proof enclosure.

1.5 Front Panel (Operator Interface)

The 2000A is housed in a rugged metal case with all controls and
displays accessible from the front panel. See Figure 1-1. The front panel
has thirteen buttons for operating the analyzer, a digital meter, and an
alphanumeric display. They are described briefly here and in detail in the
Operations chapter of this manual.

Function Keys: Six touch-sensitive membrane switches are used to

change the specific function performed by the
analyzer:

• Analyze Perform analysis for target-gas content of a sample

gas.

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1-3

1 Introduction Model 2000A-EU

Figure 1-1: Model 2000A Front Panel

• System Perform system-related tasks (described in detail in

chapter 4, Operation.).

• Span Span calibrate the analyzer.

• Zero Zero calibrate the analyzer.

• Alarms Set the alarm setpoints and attributes.

• Range Set up the user definable ranges for the instrument.

Data Entry Keys: Six touch-sensitive membrane switches are used to

input data to the instrument via the alphanumeric VFD display:

• Left & Right Arrows Select between functions currently

displayed on the VFD screen.

• Up & Down Arrows Increment or decrement values of

functions currently displayed.

• Enter Moves VFD on to the next screen in a series. If none

remains, returns to the

Analyze

screen.

1-4

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Thermal Conductivity Analyzer Introduction 1

• Escape Moves VFD back to the previous screen in a series. If

none remains, returns to the

Digital Meter Display: The meter display is a LED device that
produces large, bright, 7-segment numbers that are legible in any lighting.
It produces a continuous trace readout from 0-9999 ppm or a continuous
percent readout from 1-100 %. It is accurate across all analysis ranges.

Alphanumeric Interface Screen: The VFD screen is an easy-to-use
interface between operator and analyzer. It displays values, options, and
messages that give the operator immediate feedback.

Standby Button: The Standby turns off the display and outputs,

but circuitry is still operating.

Analyze

screen.

CAUTION: The power cable must be unplugged to fully

disconnect power from the instrument. When
chassis is exposed or when access door is open
and power cable is connected, use extra care to
avoid contact with live electrical circuits.

Access Door: For access to the thermal conductivity sensor or the
front panel electronics, the front panel swings open when the latch in the
upper right corner of the panel is pressed all the way in with a narrow
gauge tool. Accessing the main electronics circuit board requires unfasten­ing rear panel screws and sliding the electronics drawer out of the case.
(See chapter 5.)

CAUTION: The Access door must be closed and latched for

CE mark compliance to be in effect.

1.6 Recognizing Difference Between LCD & VFD

LCD has GREEN background with BLACK characters. VFD has
DARK background with GREEN characters. In the case of VFD - NO
CONTRAST ADJUSTMENT IS NEEDED.

1.7 Rear Panel (Equipment Interface)

All electrical inputs and outputs to the 2000A are made through rear­panel connectors. The connectors are described briefly here and in detail in
chapter 3, Installation.

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1 Introduction Model 2000A-EU

Figure 1-2: Model 2000A-EU Rear Panel

• Power Connection Universal AC power source.

• 9-Pin RS-232 Port Serial digital concentration signal output

and control input.

• 50-Pin Equipment Interface Port

• Analog Outputs 0-1 V dc concentration plus 0-1 V dc

range ID, and isolated 4-20 mA dc
plus 4-20 mA dc range ID.

• Alarm Connections 2 concentration alarms and 1 system

alarm.

• Remote Valve Used in the 2000 for controlling

external solenoid valves only.

• Remote Span/Zero Digital inputs allow external control

of analyzer calibration.

• Calibration Contact To notify external equipment that

instrument is being calibrated and
readings are not monitoring sample.

1-6

• Range ID Contacts Four separate, dedicated,

range-identification relay contacts
(00, 01, 02, 03).

Teledyne Analytical Instruments

Thermal Conductivity Analyzer Introduction 1

Note: If you require highly accurate Auto-Cal timing, use external

Auto-Cal control where possible. The internal clock in the
Model 2000 is accurate to 2-3 %. Accordingly, internally sched­uled calibrations can vary 2-3 % per day.

1.8 Gas Connections

The gas connectors are on the bottom of the Model 2000A chassis
near the front panel. There are no gas control valves inside the main chas­sis. Electronic input/output ports are provided on the rear panel for the
operation of solenoid valves under the complete control of the Model 2000
electronics. See section 3.3.

A sample system must be provided for introduction of zero and span
gas, as well as sample gas, into the sample path, and for controlling the
flowrates through the sample and reference paths of the analyzer. Appropri­ate pressure reducing regulators must be installed at all gas supply sources.

Gas Connector-and-Control Panels for specific applications are avail­able as extra cost additions. These panels are usually designed around a
standard manifold that attaches to the Model 2000 series analyzer below
the front panel.

For those customers wishing to incorporate their own sample controls,
the recommended system piping schematic is included among the drawings
at the rear of the manual.

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1 Introduction Model 2000A-EU

1-8

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Thermal Conductivity Analyzer Operational Theory 2

Operational Theory

2.1 Introduction

The analyzer is composed of two subsystems:

1. Thermal Conductivity Sensor

2. Electronic Signal Processing, Display and Control.

The sensor is a thermal conductivity comparator that continuously
compares the thermal conductivity of the sample gas with that of a refer­ence gas having a known conductivity.

The electronic signal processing, display and control subsystem
simplifies operation of the analyzer and accurately processes the sampled
data. A microprocessor controls all signal processing, input/output, and
display functions for the analyzer.

2.2 Sensor Theory

For greater clarity, Figure 2-1 presents two different illustrations, (a)
and (b), of the operating principle of the thermal conductivity cell.

2.2.1 Sensor Configuration

The thermal conductivity sensor contains two chambers, one for the
reference gas of known conductivity and one for the sample gas. Each
chamber contains a pair of heated filaments. Depending on its thermal
conductivity, each of the gases conducts a quantity of heat away from the
filaments in its chamber. See Figure 2-1(a).

The resistance of the filaments depends on their temperature. These
filaments are parts of the two legs of a Wheatstone bridge circuit that
unbalances if the resistances of its two legs do not match. See Figure
2-1(b).

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2 Operational Theory Model 2000A-EU

Figure 2-1: Thermal Conductivity Cell Operating Principle

If the thermal conductivities of the gases in the two chambers are
different, the Wheatstone bridge circuit unbalances, causing a current to
flow in its detector circuit. The amount of this current can be an indication
of the amount of impurity in the sample gas, or even an indication of the
type of gas, depending on the known properties of the reference and
sample gases.

The temperature of the measuring cell is regulated to within 0.1 °C by
a sophisticated control circuit. Temperature control is precise enough to
compensate for diurnal effects in the output over the operating ranges of
the analyzer. (See Specifications in the Appendix for details.)

2.2.2 Calibration

Because analysis by thermal conductivity is not an absolute measure­ment, calibration gases of known composition are required to fix the
upper and lower parameters (“zero” and “span”) of the range, or ranges, of
analysis. These gases must be used periodically, to check the accuracy of

the analyzer.

During calibration, the bridge circuit is balanced, with zero gas
against the reference gas, at one end of the measurement range; and it is
sensitized with span gas against the reference gas at the other end of the
measurement range. The resulting electrical signals are processed by the
analyzer electronics to produce a standard 0-1V, or an isolated 4–20 mA
dc, output signal, as described in the next section.

2-2

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Thermal Conductivity Analyzer Operational Theory 2

2.2.3 Effects of Flowrate and Gas Density

Because the flowrate of the gases in the chambers affects their cooling
of the heated filaments, the flowrate in the chambers must be kept as equal,
constant, and low as possible.

When setting the sample and reference flowrate, note that gases
lighter than air will have an actual flowrate higher than indicated on the
flowmeter, while gases heavier than air will have an actual flowrate lower
than indicated. Due to the wide range of gases that are measured with the
Thermal Conductivity Analyzer, the densities of the gases being handled
may vary considerably.

Then, there are limited applications where the reference gas is in a
sealed chamber and does not flow at all. These effects must be taken in
consideration by the user when setting up an analysis.

2.2.4 Measurement Results

Thermal conductivity measurements are nonspecific by nature. This
fact imposes certain limitations and requirements. If the user intends to
employ the analyzer to detect a specific component in a sample stream, the
sample must be composed of the component of interest and one other gas
(or specific, and constant, mixture of gases) in order for the measured
heat-transfer differences to be nonambiguous.

If, on the other hand, the user is primarily interested in the purity of a
process stream, and does not require specific identification of the impurity,
the analyzer can be used on more complex mixtures.

2.3 Electronics and Signal Processing

The Model 2000 Thermal Conductivity Analyzer uses an 8031 micro­controller (Central Processing Unit—CPU) with 32 kB of RAM and 128
kB of ROM to control all signal processing, input/output, and display
functions for the analyzer. System power is supplied from a universal
power supply module designed to be compatible with any international
power source. (See Major Internal Components in chapter 5 Maintenance
for the location of the power supply and the main electronic PC boards.)

The Temperature Control board is mounted on the inner face of the
rear panel, under the power input receptacle. The signal processing elec­tronics including the microprocessor, analog to digital, and digital to
analog converters are located on the Motherboard at the bottom of the case.

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2 Operational Theory Model 2000A-EU

The Preamplifier board is mounted on top of the Motherboard as shown in
the figure (in chapter 5). These boards are accessible after removing the
back panel. Figure 2-2 is a block diagram of the Analyzer electronics.

2-4

Figure 2-2: Block Diagram of the Model 2000 Electronics

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Thermal Conductivity Analyzer Operational Theory 2

The Temperature Control Board keeps the temperature of the measur­ing cell regulated to within 0.1 degree C. A thermistor is used to measure
the temperature, and a zero-crossing switch regulates the power in a car­tridge-type heater. The result is a sensor output signal that is temperature
independent.

In the presence of dissimilar gases the sensor generates a differential
voltage across its output terminals. A differential amplifier converts this
signal to a unipolar signal, which is amplified in the second stage, variable
gain amplifier, which provides automatic range switching under control of
the CPU. The output from the variable gain amplifier is sent to an 18 bit
analog to digital converter.

The digital concentration signal along with input from the control
panel is processed by the CPU and passed on to the 12-bit DAC, which
outputs 0-1 V dc Concentration and Range ID signals. An voltage-to­current converter provides 4-20 mA dc concentration signal and range ID
outputs.

The CPU also provides appropriate control signals to the Displays,
Alarms, and External Valve Controls, and accepts digital inputs for exter­nal Remote Zero and Remote Span commands. It monitors the power
supply through an analog to digital converter as part of the data for the
system failure alarm.

The RS-232 port provides two-way serial digital communications to
and from the CPU. These, and all of the above electrical interface signals
are described in detail in chapter 3 Installation.

2.4. Temperature Control

For accurate analysis the sensor of this instrument is temperature
controlled to 60oC.

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2 Operational Theory Model 2000A-EU

2-6

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Thermal Conductivity Analyzer Installation 3

Installation

Installation of the Model 2000A Analyzer includes:

1. Unpacking

2. Mounting

3. Gas connections

4. Electrical connections

5. Installing the Sensor

6. Testing the system.

3.1 Unpacking the Analyzer

The analyzer is shipped ready to install and prepare for operation.
Carefully unpack the analyzer and inspect it for damage. Immediately
report any damage to the shipping agent.

The four gas fittings that mate with the 1/8 NPT gas ports on the
Model 2000A, are not included. They must be supplied by the customer.

3.2 Mounting the Analyzer

The Model 2000A is for indoor use in a general purpose area. It is
NOT for hazardous environments of any type. It must be protected from:

• Direct sunlight

• Drafts of air

• Shock and vibration

• Temperatures below 30 °F (-1 °C) or above 110 °F (43 °C).

Locate the 2000A as close as possible, subject to the above conditions,
to the sample point to minimize effects of sample line lag time on the
analysis.

The standard model is designed for flush panel mounting. Figure 3-1 is
an illustration of the 2000A standard front panel and mounting bezel. There

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3 Installation Model 2000A-EU

are four mounting holes—one in each corner of the rigid frame. Figure
3-1a contains the hole pattern dimensions. See the outline drawing, at the
back of this manual for overall dimensions.

On special order, a 19" rack-mounting panel can be provided. For
rack mounting, one or two 2000A series analyzers are flush-panel mounted
on the rack panel. See Figure 3-1b for dimensions of the mounting panel.

6.7"

Figure 3-1a: Front Panel of the Model 2000A

Figure 3-1b: Single and Dual 19" Rack Mounts

5.75

5.75

8.75

8.75

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Teledyne Analytical Instruments

Thermal Conductivity Analyzer Installation 3

All operator controls are mounted on the control panel, which is
hinged on the left edge and doubles as the door that provides access to the
sensor inside the instrument. The door is spring loaded and will swing open
when the button in the center of the latch (upper right corner) is pressed all
the way in with a narrow gauge tool (less than 4.5 mm wide), such as a
small hex wrench or screwdriver Allow clearance for the door to open in a
90-degree arc of radius 19.3 cm. See Figure 3-2.

Figure 3-2: Required Front Door Clearance

3.3 Electrical Connections (Rear Panel)

Figure 3-3 shows the Model 2000A-EU rear panel. There are connec­tors for power, digital communications, and both digital and analog con­centration output.

Figure 3-3: Rear Panel of the Model 2000A-EU

Teledyne Analytical Instruments

3-3

3 Installation Model 2000A-EU

For safe connections, no uninsulated wiring should be able to come in

contact with fingers, tools or clothing during normal operation.

CAUTION: Use Shielded Cables. Also, use plugs that provide

excellent EMI/RFI protection. The plug case must
be connected to the cable shield, and it must be
tightly fastened to the analyzer with its fastening
screws. Ultimately, it is the installer who ensures
that the connections provide adequate EMI/RFI
shielding.

3.3.1 Primary Input Power

The power cord receptacle and fuse block are located in the same

assembly. Insert the power cord into the power cord receptacle.

DANGER: POWER IS APPLIED TO THE INSTRUMENT'S CIR-

CUITRY AS LONG AS THE INSTRUMENT IS CON­NECTED TO THE POWER SOURCE. THE STANDBY
ON THE FRONT PANEL IS FOR SWITCHING
POWER ON OR OFF TO THE DISPLAYS AND OUT­PUTS ONLY.

The standard power supply requires a 110 V ac, 50-60 Hz power
source. If you have the -N option, you will require 220 V ac, 50-60 Hz
power.

3.3.2 Fuse Installation

The fuse block, at the right of the power cord receptacle, accepts US
or European size fuses. A jumper replaces the fuse in whichever fuse
receptacle is not used. Fuses are not installed at the factory. Be sure to
install the proper fuse as part of installation. (See Fuse Replacement in
chapter 5, maintenance.)

3.3.3 50-Pin Equipment Interface Connector

Figure 3-4 shows the pin layout of the Equipment Interface connector.
The arrangement is shown as seen when the viewer faces the rear panel of
the analyzer. The pin numbers for each input/output function are given
where each function is described in the paragraphs below.

3-4

Teledyne Analytical Instruments