Teledyne 300P User Manual
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OPERATING INSTRUCTIONS
FOR
Model 300P
Percent Oxygen Transmitter
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 M50965
08/06/99
ECO # 99-0323
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Model 300PModel 300P
Model 300P
Model 300PModel 300P
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 (TAI), 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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Table of Contents
1 Introduction
1.1 General .......................................................................... 1-1
1.2 Features......................................................................... 1-1
1.3 Typical Applications....................................................... 1-2
2 Operational Theory
2.1 Transmitter Description.................................................... 2-1
2.2 Sensor Description.......................................................... 2-1
2.3 Circuit Description ......................................................... 2-2
2.4 RFI Protection ................................................................ 2-3
3 Operation
3.1 Installation...................................................................... 3-1
3.1.1 System Power Requirements................................. 3-1
3.1.2 Transmitter ............................................................. 3-1
3.1.3 Junction Box .......................................................... 3-1
3.2 Calibration ..................................................................... 3-2
3.2.1 Installing the Milliammeter ..................................... 3-2
3.2.2 Setting the Electronic Zero (P2) ............................. 3-3
3.2.3 Setting the Span Pot (P1)....................................... 3-3
3.3 Operating The Oxygen T ransmitter................................. 3-3
4 Maintenance
4.1 Routine Maintenance..................................................... 4-1
4.2 Cell Replacement .......................................................... 4-1
4.3 Cell Warranty ................................................................. 4-2
Appendix
Specifications ........................................................................ A-1
Recommended Spare Parts List ............................................ A-2
Drawing List........................................................................... A-2
Teledyne Analytical Instruments
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Model 300PModel 300P
Model 300P
Model 300PModel 300P
Model 300P 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:
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.
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Introduction
1.1 General
The Model 300P Percent Oxygen Transmitter is designed to accurately monitor the oxygen content on a percent basis in a wide variety of
gases. The Percent Oxygen Transmitter is equipped with two oxygen
analysis ranges, 0–25% and 0–20.9% (air calibration range). The Model
300P is approved by Factory Mutual (FM) as intrinsically safe for operation in Class 1, Division 1, Groups A, B, C, and D hazardous environments.
The heart of the transmitter is Teledyne Brown Engineering's MicroFuel Cell oxygen sensor. This cell is a sealed electrochemical device which
translates the amount of oxygen present in a sample into an electrical
current. Since it is sealed, there is no electrolyte to change or electrodes to
clean and therefore, virtually maintenance free.
The transmitter operates from a 24 VDC (nominal) power source and
produces a 4–20 mA dc current output that is directly and linearly proportional to the oxygen concentration. The output current is used to interface
with devices such as recorders, alarms, computers or other current driven
devices.
1.2 Features
The following features describe the basic model. The exact configuration depends on the options selected at the time of purchase.
• Two analysis ranges: 0–25% and 0–20.9%
• High sensitivity (0.5%)
• Accurate (±2% of full scale at constant temperature and
pressure of calibration) or ±5% of full scale over the operating
temperature range.
Teledyne Analytical Instruments
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1 1
1 Introduction Model 300P
1 1
• Insensitive to flow variations
• Fast response and recovery
• Long life, maintenance-free Micro-Fuel Cell oxygen sensor
• Unaffected by reducing agents (HC's, CO, SO2, etc.)
• Easy to calibrate, no zero gas required
• RFI Protection
• 2-wire (loop-powered) with 4–20 mA dc output
• Rugged bulkhead mounted metal enclosure
• FM approved as intrinsically safe (when used with approved
safety barriers)
• Compact size, easy to install
1.3 Typical Applications
The Model 300P Percent Oxygen Transmitter is capable of monitoring oxygen at the % level in a variety of gases. It is widely used in industry. A few typical applications are:
• Monitoring inert gas blanketing
• Air separation and liquefaction
• Chemical feedstock analysis
• Semiconductor manufacturing
• Petrochemical process control
• Heat treating and bright annealing processes
• Quality assurance
• Gas certification
• Welding applications
• Flue gas analysis.
1-2
Teledyne Analytical Instruments
Percent Oxygen Transmitter Operational Theory 2
Operational Theory
2.1 Transmitter Description
The transmitter consists of an RFI proof enclosure which contains the
O2 Sensor Assembly, 2-Wire Transmitter Circuitry and RFI Filters.
Mounted on the left side is a junction box which contains a three conductor
terminal strip for all external electrical connections. The bottom of the box
contains two bulkhead fittings for the 1/8" tubing used for bringing the
sample into and out of the sensor assembly. The transmitter assembly
contains four holes in the mounting flange for vertical surface mounting.
Access to the junction box is obtained by the removal of two screws
followed by the removal of the cover. Access to the O2 sensor and PC
board is through an RFI gasketed door held shut by 4 screw clamps.
2.2 Sensor Description
The Micro-Fuel Cell is a sealed plastic disposable oxygen transducer
that measures 1¼ inches in diameter and is ¾ inch thick (see Figure 2-1).
Inside of the cell are a cathode and anode immersed in 15% aqueous KOH
electrolyte. At one end of the sensor is a Teflon diffusion membrane; the
other end is sealed with a polyethylene membrane. At the rear of the cell is
a contact plate consisting of
two concentric foils. The
Top View
Bottom View
foils mate with springloaded contacts in the sensor
Screen
Concentric Foil
Contact Rings
block assembly and provide
the electrical connection to
the rest of the analyzer.
The sensing cathode,
located beneath the diffu-
Figure 2-1: Micro-Fuel Cell
Teledyne Analytical Instruments
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2 2
2 Operational Theory Model 300P
2 2
sion membrane, has a surface area of 2.48 cm2. The sample gas enters the
sensor block through an inlet tube between the cathode and the sensor
block cap, diffuses through the Teflon membrane, and any oxygen in the
sample gas is reduced on the surface of the cathode by the following
mechanism:
O2 + 2H2O + 4e
––
–
––
→ 4OH
––
–
––
(cathode)
When the oxygen is reduced at the cathode, lead is simultaneously
oxidized at the anode by the following mechanism.
––
–
2Pb → 2Pb+2 + 4e
––
(anode)
The electrons released at the surface of the anode flow to the cathode
surface via an external circuit. This current is proportional to the amount of
oxygen. It is measured and used to determine the oxygen concentration in
the gas mixture.
The overall reaction for the fuel cell is:
2Pb + O2 → 2PbO
The output of the fuel cell is limited by the amount of oxygen in the
cell at any one time, and the amount of stored anode material. In the
absence of oxygen, there is no current generated.
Warning: The sensor used in the Model 300P uses electrolytes which
contain substances that are extremely harmful if touched,
swallowed, or inhaled. Avoid contact with ANY fluid or powder
in or around the unit. What may appear to be plain water could
contain one of these toxic substances. In case of eye contact,
immediately flush eyes with water for at least 15 minutes. Call
physician. (See Appendix - Material Safety Data Sheet (MSDS)).
2.3 Circuit Description
The 300P circuitry consists of four stages: an input stage, a temperature compensation/ gain stage, a low-pass filter and an output voltage-tocurrent stage. The output of the O2 cell is a current directly proportional to
the amount of oxygen present. The input stage converts this current to a
voltage signal.
The temperature compensation stage consists of circuitry that amplifies the signal by a factor which is dependent upon the O2 cell temperature.
This temperature dependent gain is used to compensate for the rise in
output current of the O2 cell with temperature. A thermistor mounted in
the sensor assembly monitors this temperature and changes resistance (up
2-2
Teledyne Analytical Instruments
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