Teledyne 2020 User Manual

Thermal Conductivity Analyzer

OPERATING INSTRUCTIONS FOR

Model 2020

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 M67677

08/06/1999

ECO # 99-0323

i

Model 2020

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
acknowledgments 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: _______________________

Standard Options Included in the Instrument with the Above Serial Number:

q 2020L: Gas selector panel consisting of sample/ref flow meters with

stainless steel control valves, tubing and fittings.

q 2020C: Auto Calibration valves (zero/span) built-in gas selector panel

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

q 2020R: Sealed reference TC cell (application dependent, contact

factory).

Special Options:

q 2020F: Groups C & D Flame Arrestors with Flow Control Gas Panel.
q 2020H: Stainless Cell Block with Gold Filaments.
q 2020O: Groups B Flame Arrestors with Flow Control Gas Panel.
q 2020P: Groups C & D Flame Arrestors with Cal Valves and Flow

Control Gas Panel.

q 2020Q: Groups B Flame Arrestors with Cal Valves and Flow Control

Gas Panel.

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Model 2020

1 Introduction

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

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

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

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

1.5 Operator Interface (Front Panel) .................................... 1-3

1.5.1 UP/DOWN Switch................................................ 1-4

1.5.2 ESCAPE/ENTER Switch ..................................... 1-5

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

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

1.8 Gas Connections ........................................................... 1-6

2 Operational Theory

Table of Contents

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 Primar y Input Power .............................................. 3-3

3.3.2 Fuse Installation..................................................... 3-4

3.3.3 Voltage Selections ................................................. 3-4

3.3.4 Analog Outputs...................................................... 3-4

3.3.5 Alarm Relays ......................................................... 3-6

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

3.3.7 Range ID Relays.................................................... 3-8

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

3.3.9 RS-232 Port ........................................................... 3-9

3.3.10 Remote Probe Connector ...................................... 3-10

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

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

3.4.2 Pressure and Flow Rate Regulation ......................3-14

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Thermal Conductivity Analyzer

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

3.4.4 SAMPLE Gas.........................................................3-15

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

3.4.6 ZERO Gas .............................................................3-16

3.4.7 SPAN Gas..............................................................3-16

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

4 Operation

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

4.2 Using the Data Entry and Function Buttons................... 4-2

4.2.1 Mode/Function Selection ....................................... 4-2

4.2.1.1 Analysis Mode ............................................... 4-2

4.2.1.2 Setup Mode ................................................... 4-4

4.2.2 Data Entry.............................................................. 4-5

4.2.2.1 ENTER .......................................................... 4-5

4.2.2.2 Escape........................................................... 4-5

4.3 The

4.3.1 Setting the Display................................................. 4-6

4.3.2 Setting up an Auto-Cal........................................... 4-6

4.3.3 Password Protection .............................................. 4-7

4.3.4 Logging Out ........................................................... 4-10

4.3.5 System Self-Diagnostic Test .................................. 4-10

4.3.6 The Model Screen ................................................. 4-11

4.3.7 Checking Linearity with Algorithm.......................... 4-11

4.4 The

4.4.1 Zero Cal ................................................................. 4-13

4.4.2 Span Cal................................................................ 4-16

4.5 The

4.6 The

4.6.1 Manual (Select/Define Range) Screen .................. 4-20

4.6.2 Auto (Single Application) Screen ........................... 4-20

4.6.3 Precautions............................................................ 4-22

4.7 The

4.8 Programming ................................................................. 4-23

System

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

4.3.3.2 Installing or Changing the Password ............. 4-8

Zero

4.4.1.1 Auto Mode Zeroing ........................................ 4-13

4.4.1.2 Manual Mode Zeroing.................................... 4-14

4.4.1.3 Cell Failure..................................................... 4-15

4.4.2.1 Auto Mode Spanning ..................................... 4-16

4.4.2.2 Manual Mode Spanning................................. 4-17

Alarms
Range

Analyze

Function..................................................... 4-6

and

Span

Functions ....................................... 4-12

Function...................................................... 4-17

Select Function ........................................... 4-19

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

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Model 2020

4.8.1 The Set Application Screen ................................... 4.24

4.8.2 The Curve Algorithm Screen ................................. 4-26

4.9 Special Function Setup.................................................. 4-29

4.9.1 Output Signal Reversal.......................................... 4.29

4.9.2 Polarity Reversal.................................................... 4-30

4.9.3 Gain Preset............................................................ 4.31

Maintenance

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

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

5.3 Fuse Replacement......................................................... 5-2

5.4 Major Internal Components ........................................... 5-3

5.5 Voltage Selections ......................................................... 5-3

5.6 Cell, Heater, 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

5.6.4 Replacing the Heater and/or Thermocouple .......... 5-8

5.7 Cleaning......................................................................... 5-9

5.8 Phone Numbers............................................................. 5-9

4.8.2.1 Checking the Linearization ............................ 4-26

4.8.2.2 Manual Mode Linearization............................ 4-27

4.8.2.3 Auto Mode Linearization................................ 4-28

4.9.1.1 Output Signal Reversal.................................. 4-29

4.9.1.2 Output Signal Offset ...................................... 4-30

Appendix

vi

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

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

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

Teledyne Analytical Instruments

Thermal Conductivity Analyzer Introduction 1

Introduction

1.1 Overview

The Analytical Instruments Model 2020 Thermal Conductivity Ana­lyzer, explosion proof, UL and CSA listed for class 1, DIV 1, Groups B, C,
and D service, is a versatile microprocessor-based instrument for measur­ing a component gas in a background gas, or in a specific mixture of
background gases. It compares the thermal conductivity of a sample stream
with that of a reference gas of known composition. The 2020 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 2020 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, and the sophisticated user can
add his own unique applications.

Many of the Model 2020 features covered in this manual are optional,
selected according to the customers specific application. Therefore, the user
may 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 Introduction Model 2020

1.2 Typical Applications

A few typical applications of the Model 2020 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 2020 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.

• Six adjustable set points concentration with two alarms and a
system failure alarm relays.

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

1-2

• Sample and Hold for holding analyzer’s output during Auto
calibration mode.

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

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Thermal Conductivity Analyzer Introduction 1

• 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.)

• Standard, proven sensor cell design.

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

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

• Auto and remote calibration capabilities.

• 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 2020 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
matter of this manual for those that apply to your Model 2020 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 Operator Interface (Front Panel)

The Model 2020 is housed in a explosion proof housing. See Figure 1-

1. The front panel has two single operator controls, a digital meter, and an
alphanumeric display. They are described briefly here and in detail in the
Operations chapter of this manual.

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1 Introduction Model 2020

Figure 1-1: Model 2020 Front Panel

1.5.1 UP/DOWN Switch

Functions: The UP/DOWN switch is used to select the function to be

performed. Choose UP or DOWN to scroll through the following list of
fourteen functions:

• AUTO-CAL Set up an automatic calibration sequence.

• PSWD Install a password to protect your analyzer setup.

• LOGOUT Locks Setup Mode.

• MODEL Displays model and version of analyzer.

• SELF-TEST Runs internal diagnostic program, displays results.

• SPAN Span calibrate the analyzer.

• ZERO Zero calibrate the analyzer.

• ALARMS Set the alarm setpoints and attributes.

• RANGE Set up the 3 user definable ranges for the instrument.

• APPLICATION Set up the 3 definable application ranges

• ALOGORITHM Set up the linearization

1-4

• CAL-INDEPD Calibration range independently

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Thermal Conductivity Analyzer Introduction 1

• CONTRAST Adjust LCD contrast.

• STANDBY Leave analyzer powered, but no outputs or displays.

Contrast Function is

(Refer to Section 1.6)

DISABLED

WARNING: THE POWER CABLE MUST BE DISCONNECTED TO

FULLY REMOVE POWER FROM THE INSTRUMENT.

Subfunctions: Once a Function is entered, the UP/DOWN switch is
used to select between any subfunctions displayed on the VFD screen.

Parameter values: When modifiable values are displayed on the
VFD, the UP/DOWN switch can be used to increment or decrement the
values.

1.5.2 ESCAPE/ENTER Switch

Data Entry: The ESCAPE/ENTER switch is used to input data, from

the alphanumeric VFD screen into the instrument:

• Escape Moves VFD display back to the previous screen in a

series. If none remains, returns to the
With subfunction selected, moves VFD back through

items on screen, to first item, then moves VFD to
previous display.

Analyze

screen.

• Enter With a Subfunction Selected: Moves VFD on to the

next screen in a series. If none remains, returns to the

Analyze

With a Value Selected: Enters the value into the
analyzer as data. Advances VFD to next operation.

(See Chapter 4 for details.)

screen.

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 Equipment Interface

The electrical connection are described briefly here and in detail in
chapter 3, Installation.

Electrical Connections: The electrical connections on the electrical
connector panel are described briefly here, and in more detail in chapter 3
Installation.

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1 Introduction Model 2020

• Power Connection 115 or 230 V dc, 50 or 60 Hz.

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

range ID. Additional, isolated 4-20 mA
dc plus 4-20 mA dc range ID available.

• Alarm Connections 2 concentration alarms and 1 system

alarm.

• RS-232 Port Serial digital concentration signal

output and control input.

• Remote Valves Used for controlling external solenoid

valves, if desired.

• Remote Sensor Used for external sensor and

thermocouple, if desired.

• 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.

• Range ID Contacts Four separate, dedicated, range relay

contacts. Low, Medium, High, Cal.

• Network I/O Serial digital communications for local

network access. For future expansion.
Not implemented at this printing.

1.8 Gas Connections

The gas connectors are on the bottom of the Model 2020 chassis near

the front doorl.

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-Selector Panels for specific applications are
available at additional cost. These panels are optional designed to substitute
a standard 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.

1-6

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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 2020

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 2020 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 under the electrical
connection board.. The signal processing electronics including the micro­processor, analog to digital, and digital to analog converters are located on
the Motherboard at the front door of the unit. The Preamplifier board is

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2 Operational Theory Model 2020

mounted on top of the Motherboard as shown in the figure 5.4. 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 2020 Electronics

Teledyne Analytical Instruments

Thermal Conductivity Analyzer Operational Theory 2

The Temperature Control 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 cartridge­type 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 Gas Selec­tor 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 2020

2-6

Teledyne Analytical Instruments

Thermal Conductivity Analyzer Installation 3

Installation

Installation of the Model 2020 Analyzer includes:

1. Unpacking

2. Mounting

3. Gas connections

4. Electrical connections

5. 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 1/4 NPT gas ports on the
Model 2020, are not included. They must be supplied by the customer.

3.2 Mounting the Analyzer

The Model 2020 is designed for bulkhead mounting in hazardous
environments. There are four mounting lugs—one in each corner of the
enclosure, as shown in Figure 3-1. The outline drawing, at the back of this
manual, gives the mounting hole size and spacing. The drawing also con­tains the overall dimensions. Do not forget to allow an extra 13/8" for the
hinges.

Be sure to allow enough space in front of the enclosure to swing the
door open—a 16 1/4" radius, as shown in Figure 3-2.

All electrical connections are made via cables which enter the explo­sion-proof housing through ports in its side. No conduit fittings are sup­plied. The installer must provide two 3/4" NPT and two 1" NPT adapters
and the appropriate sealing conduit.

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3-1

3 Installation Model 2020

Hinge

3-2

Figure 3-1a: Internal Views of the Model 2020

H

Teledyne Analytical Instruments

Thermal Conductivity Analyzer Installation 3

Figure 3-2: Required Front Door Clearance

3.3 Electrical Connections

Figure 3-3 shows the Model 2020 Electrical Connector Panel. There
are terminal blocks for connecting power, communications, and both
digital and analog concentration outputs.

For safe connections, ensure that no uninsulated wire extends outside
of the connectors they are attached to. Stripped wire ends must insert
completely into terminal blocks. No uninsulated wiring should be able to
come in contact with fingers, tools or clothing during normal operation.

3.3.1 Primary Input Power

The power cord receptacle and fuse block are located in the same
assembly. Insert the female plug end of 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
FUNCTION IS FOR SWITCHING POWER ON / OFF
TO THE DISPLAY AND OUTPUTS ONLY.

The standard power supply requires a 115 V ac, 50-60 Hz power
source. If you have the -N option, you will require 220 V ac, 50-60 Hz
power.

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3 Installation Model 2020

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. Be sure to install the proper fuse as part of installa­tion. (See Fuse Replacement in chapter 5, maintenance.)

3.3.3 Voltage Selections

There is a switch on the interface board, inside the instrument, that
selects the working voltage between 230/115 VAC.

230V

115V

Voltage Selector Switch

Make sure the switch is in the proper position before
powering the instrument.

3.3.4 Analog Outputs

There are four DC output signal connectors on the panel. There are
two wires per output with the polarity noted. See Figure 3-4. The outputs
are:

0–1 V dc % of Range: Voltage rises linearly with increasing concentra-

tion, from 0 V at 0 concentration to 1 V at full
scale. (Full scale = 100% of programmable range.)

0–1 V dc Range ID: 0.25 V = Range 1, 0.5 V = Range 2, 0.75 V =

Range 3, 1 V = Cal Range.

4–20 mA dc % Range: Current rises linearly with concentration, from 4

mA at 0 concentration to 20 mA at full scale. (Full
scale = 100% of programmable range.)

4–20 mA dc Range ID: 8 mA = Range 1, 12 mA = Range 2, 16 mA =

Range 3, 20 mA = Range 4.

3-4

Teledyne Analytical Instruments

Thermal Conductivity Analyzer Installation 3

Figure 3-4: Analog Output Connections

Examples:

The analog output signal has a voltage which depends on gas concen-

tration relative to the full scale of the range. To relate the signal output to
the actual concentration, it is necessary to know what range the instrument
is currently on, especially when the analyzer is in the autoranging mode.

The signal output for concentration is linear over the currently se­lected analysis range. For example, if the analyzer is set on a range that
was defined as 0–10 % hydrogen, then the output would be as shown in
Table 3-1.

Table 3-1: Analog Concentration Output—Example

Percent Voltage Signal Current Signal
Hydrogen Output (V dc) Output (mA dc)

0 0.0 4.0
1 0.1 5.6
2 0.2 7.2
3 0.3 8.8
4 0.4 10.4
5 0.5 12.0
6 0.6 13.6
7 0.7 15.2
8 0.8 16.8
9 0.9 18.4

10 1.0 20.0

Teledyne Analytical Instruments

3-5

3 Installation Model 2020

To provide an indication of the range, the Range ID analog output
terminals are used. They generate a steady preset voltage (or current when
using the current outputs) to represent a particular range. Table 3-2 gives
the range ID output for each analysis range.

Table 3-2: Analog Range ID Output—Example

Range Voltage (V) Current (mA) Application

Range 1 0.25 8 0-1 % H2 in N2
Range 2 0.50 12 0-10 % H2 in N2
Range 3 0.75 16 0-1 % H2 in Air
Range 4 (Cal) 1.00 20 0-1 % H2 in N2

3.3.5 Alarm Relays

The three alarm-circuit connectors are spring terminals for making
connections to internal alarm relay contacts. Each provides a set of Form
C contacts for each type of alarm. Each has both normally open and nor­mally closed contact connections. The contact connections are indicated by
diagrams on the rear panel. They are capable of switching up to 3 amperes
at 250 V ac into a resistive load. See Figure 3-5. The connectors are:

Threshold Alarm 1: • Can be configured as high (actuates when concen-

tration is above threshold), or low (actuates when
concentration is below threshold).

• Can be configured as fail-safe or non-fail-safe.

• Can be configured as latching or nonlatching.

• Can be configured out (defeated).

Threshold Alarm 2: • Can be configured as high (actuates when concen-

tration is above threshold), or low (actuates when
concentration is below threshold).

• Can be configured as fail-safe or non-fail-safe.

• Can be configured as latching or nonlatching.

• Can be configured out (defeated).

System Alarm: Actuates when DC power supplied to circuits is

unacceptable in one or more parameters. Perma­nently configured as fail-safe and latching. Cannot
be defeated.

3-6

Actuates when cell can not balance during zero
calibration.

Actuates when span parameter out off its limited
parameter.

Teledyne Analytical Instruments