Teledyne MD300 User Manual

Portable Oxygen Monitor

P/N M/AD/MD300

06-23-2010

OPERATING & SERVICE INSTRUCTIONS FOR

AD300

PORTABLE OXYGEN ANALYZER

MD300

PORTABLE OXYGEN MONITOR

TYPE B EQUIPMENT: Equipment providing a particular degree

of protection against electric shock,
particularly regarding—

• Allowable LEAKAGE CURRENT

• Reliability of the protective earth

connection (if present).

Teledyne Analytical Instruments i

AD300/MD300

Copyright © 2010 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, optical,
manual, or otherwise, without prior written consent of Teledyne Instruments,
Analytical Instruments, 16830 Chestnut Street, City of Industry, CA 91749-1580

FCC Statement

This equipment generates and uses radio frequency energy, and if not installed and
used in strict accordance with the manufacturer's instruction manual, may cause
interference to radio and TV communications. It has been type-tested and certified to
comply with the limits for a Class A, and exceeds limits for a Class B, computing
device pursuant to Subpart J of FCC Rules, which are designed to provide reasonable
protection against such interference when installed in a commercial and residential
environment. Operation of this equipment in a residential area may cause interference,
in which case the user, at his own expense, will be required to take whatever measures
may be required to correct the interference.

Note: The above statement is required by the FCC for any device

that incorporates microprocessors.

Warranty

Teledyne warrants that the goods are free from defects of material and of construction
for a period of 2 years from the date of shipment from Teledyne. The Class R-17S
Micro-Fuel Cell is warranted for two years from the date of shipment from Teledyne.
The liability of Teledyne if any; shall be limited solely to the replacement and repair of
the goods and shall not include shipping costs or other incidental damages as defined in
Section 2-715 of the U.S. Uniform Commercial Code.

This warranty is null and void if any goods are subjected to misuse, negligence,
accident, or repairs other than those performed by Teledyne or an authorized service
center.

Teledyne Analytical Instruments ii

Portable Oxygen Monitor

About This Manual

The AD300/MD300 Operator's Manual provides both introductory
and detailed information for configuring and operating these
instruments. The manual takes you from the time you unpack the
instrument until you complete the first gas analysis. The bulk of the
manual contains operating procedures and information. There are also
cautions, warnings, and guidelines to ensure that your monitor operates
normally and to its full potential. A troubleshooting section is available
to assist you with common problems and a complete product
specifications and spare parts list is included as an appendix.

A Quick start manual is also supplied which provides the minimum
information you need to use the instrument immediately.

Chapter 1: An introduction to the monitor and its components,

features and applications

Chapter 2: Step-by-step set-up procedures and information
Chapter 3: A guide for daily operational maintenance and

troubleshooting

Appendix: Specifications and available spare part options for the

monitor, and detailed application considerations to aid in
troubleshooting, etc.

How To Use This Manual

This manual is designed to walk you through the initial set-up of the
AD300 Portable Oxygen Analyzer and MD300 Portable Oxygen Monitors. It
also serves as a quick reference guide to help you with specific questions or
operating problems.

Before turning the instrument on, you are advised to read the safety
information on the next few pages and the information found in
Chapters 1 and 2. These Chapters acquaint the user with the instruments
use and operation before placing it into operation.

Teledyne Analytical Instruments iii

AD300/MD300

Safety Messages

Your safety and the safety of others are very important. Please

carefully read the following safety messages.

Safety message are indented to alert the user of potential hazards.
Each safety message is associated with a safety alert symbol. These
symbols are found in the manual and on the instrument. The definition
of these symbols is described below:

CAUTION: Refer to the instructions for details on the
specific danger. These caution symbols warn of specific
procedures, which if not followed could cause bodily Injury,
and/or damage the instrument.

WARNING: This symbol is use to alert the operator of a
condition that could cause bodily harm.

NOTE: Additional information and comments regarding a
specific component or procedure are highlighted in the form
of a note.

CAUTION: THE MONITOR SHOULD ONLY BE USED FOR THE

PURPOSE AND IN THE MANNER DESCRIBED IN
THIS MANUAL.

IF YOU USE THE ANALYZER IN A MANNER OTHER
THAN THAT FOR WHICH IT WAS INTENDED,
UNPREDICTABLE BEHAVIOR COULD RESULT
POSSIBLY ACCOMPANIED WITH HAZARDOUS
CONSEQUENCES.

Teledyne Analytical Instruments iv

Portable Oxygen Monitor

Table of Contents

Safety Messages .......................................................................... iv

List of Figures .............................................................................. vii

List of Tables .............................................................................. viii

Introduction ................................................................................... 9

1.1 Features 11

1.2 Options 11

1.3 The R17S Sensor—How it works 12

Operation ..................................................................................... 13

2.1 Setup 13

2.1.1 Sensor Installation or Replacement 13

2.1.2 Mounting 15

2.1.2.1 V-Mount Adapter Installation 15

2.1.2.2 Universal Mounting Clamp Installation 16

2.1.3 Battery Installation 16

2.1.4 Calibration 18

2.1.5 Alarms (MD300 only) 20

2.1.6 Output 0-1 VDC or RS232 21

2.2 Use 22

2.2.1 Gas Sampling 22

2.3 Gas Sampling/Sensor Issues 24

2.3.1 Temperature 24

2.3.2 Pressure 25

2.3.3 Humidity 25

2.3.4 Discrepancy in Readings 26

Teledyne Analytical Instruments v

AD300/MD300

2.4 Do’s and Don’ts 27

Service Manual ............................................................................ 29

3.1 General Service Information 29

3.2 Overall Maintenance 29

3.3 Battery Maintenance 29

3.4 Sensor Maintenance 30

3.5 Gas Sampling 30

3.5.1 Discrepancy in Readings 30

3.6 Troubleshooting 31

3.7 Watchdog 34

3.8 Other Problems with the Instrument 36

3.9 Return Authorization for Service 36

Appendix ...................................................................................... 37

A.1 Specifications 37
A.2 Spare Parts List 38
A.3 Optional Accessories 38

Index ....................................................Error! Bookmark not defined.

Teledyne Analytical Instruments vi

Portable Oxygen Monitor

List of Figures

Figure 1-1: MD300 Front View ........................................................ 9

Figure 1-2: AD300 Front View ....................................................... 10

Figure 2-1: Installing the R17S Sensor .......................................... 14

Figure 2-2: Sensor Cable Connection to Monitor ......................... 14

Figure 2-3: Mounting the Sensor in the Tee Adapter ..................... 15

Figure 2-4: V-Mount Adapter Installation ....................................... 16

Figure 2-5: Brass Insert for Universal Mounting Clamp ................. 16

Figure 2-6: Installing Batteries ....................................................... 17

Figure 2-7: Calibration Sequence ................................................ 178

Figure 2-8: Setting the Alarms (MD300) ........................................ 20

Figure 2-9: 0-1 VDC or RS 232 Digital Output Port ....................... 22

Figure 2-10: Low Pressure Gas Sampling ..................................... 23

Figure 2-11: High Pressure Gas Sampling .................................... 24

Teledyne Analytical Instruments vii

AD300/MD300

List of Tables

Table 3-1 Troubleshooting ............................................................ 31

Table 3-2 Error Codes ................................................................... 35

Teledyne Analytical Instruments viii

Oxygen Analyzer Introduction

Introduction

The Teledyne Analytical Instruments AD300 Oxygen Analyzer
here after referred to as AD300 and MD300 Oxygen Monitors with
alarms here after referred to as MD300 are portable instruments that
provide fast and accurate oxygen monitoring. In addition, the model
MD300 incorporates an audio/visual alarm capability. These instruments
are designed to monitor up to 100% oxygen concentration in breathable
gas mixtures. Because they are microprocessor-based, the AD/MD300
series have a unique combination of features that make them very easy
to use. The operator interface is accomplished through a series of
buttons located conveniently on the front face of the instrument. The
MD300 front face interface is shown in Figure 1-1. The AD300 is
similar but without the battery and alarm test buttons is shown in Figure
1-2.

Figure 1-1: MD300 Front View

Teledyne Analytical Instruments 9

Introduction AD300/MD300

Figure 1-2: AD300 Front View

The LCD display consists of up to 3.5 characters plus a decimal
point indicator capable of displaying up to 105%. (See Section 1.2
Options for alternate display configuration). An integral battery life

indicator is displayed continuously on the AD300 and ―on demand‖

with the MD300.

The instrument is powered by three AA alkaline batteries and is
designed to operate for 2000 hours in Non-alarm State.

Oxygen analysis is linear across the single range of 0-100% using
Teledyne’s class R17S oxygen sensor. A unique sensor failure alarm is
incorporated which warns the user if the sensor signal is lost or low.
When this occurs, the √ SENSOR display flashes. The alarm buzzer can
be silenced by pressing the ALARM SILENCE key. If the alarm
condition is not corrected within 115 seconds the alarm buzzer will
reactivate.

The MD300 unit incorporates a dual concentration alarm with
individual user-defined set points. The set points are displayed on the
lower portion of the LCD display with the low alarm set point appearing
at the lower left and the high alarm appearing on the lower right of the
display. The alarm circuitry provides both an audible and visual alarm.

Teledyne Analytical Instruments 10

Oxygen Analyzer Introduction

1.1 Features

The AD300/MD300 are rugged, versatile instruments capable of
rapidly measuring the oxygen content of breathing gases commonly used
for diving purposes. Gas analysis is accurate to within ±2% of full scale
over the operating range of 0-100% at constant temperature and pressure.

The following features are standard on the AD300 and MD300
instruments:

Large easy to read 3 1/2 digit LCD display (see options)
Automatic LCD back lighting upon key press
Microprocessor controlled
Up/Down front panel controls
Sensor fail/disconnect alarm indicator (audible and visual)
Alarm silence button
2000 operating hours from 3 AA alkaline batteries
Battery status indicator
Rugged high impact ABS construction
Splash resistant case.
Long life (36 months in air) class R17S sensor
VDC digital output (optional RS-232)

The MD300 features include the above plus:

User defined set point controlled concentration alarms
Battery test function

1.2 Options

The following instrument options are available for both the AD300
and MD300 units:

A-Option—3-digit LCD display instead of 3 1/2 digit
B-Option—RS 232 digital output instead of 0-1VDC

Teledyne Analytical Instruments 11

Introduction AD300/MD300

Note: Contact the factory for retrofitting an existing instrument for

3 digit LCD display. For RS-232 reconfiguration, see
Section 2.1.6.

In addition to the above instrument configuration options, the

following optional equipment is available for your instrument:

DIN flow restrictor for sampling gas cylinder directly

P/N (B 75401)
Universal Pole Mounting Clamp (P/N CP 2343)
V-Mount Wall Adapter P/N B 647)
0-1 VDC Interface Cable (P/NB-75554)
RS 232 Interface Cable (P/N B-75555)

1.3 The R17S Sensor—How it works

The AD300/MD300 uses Teledyne Analytical Instruments Patented
R17S disposable oxygen sensor. The sensor is made up of a sensing
cathode and anode (fuel) immersed in electrolyte and packaged in a
small plastic container. Oxygen entering the sensor reacts with the anode
and a proportional current is collected at the sensing cathode. This
current is sent to the electronics where it is converted into a digital
signal and displayed on the LCD Screen.

A flow diverter is supplied with each R17S sensor for use with the

blue ―T‖ adapter. The flow diverter threads onto the end of the sensor

and facilitates the transport of gas into the sensor.

The diverter should be removed for ambient air sampling such as a
diving bell.

CAUTION: REMOVE AND SAVE THE DIVERTER WHEN THE

SENSOR IS USED IN CONFINED VOLUME
APPLICATIONS.

Teledyne Analytical Instruments 12

Portable Oxygen Monitor Operation

Operation

Note: Upon receipt, INSPECT THE ENTIRE UNIT FOR

DAMAGE. Check the unit and all included accessories for
broken or loose parts. If damaged, DO NOT USE. Notify
the shipper, and consult Teledyne Analytical Instruments.

Note: This equipment is internally powered using 3 AA batteries.

2.1 Setup

To set up and use your AD300 analyzer or MD300 monitor:

1. Install the sensor.

2. Install the batteries.

3. Calibrate the unit.

4. Set the alarms (MD300 only).

The control keys are designed for easy operation. A LOCK/UNLOCK
key has been incorporated to prevent accidental changes to critical settings.
This eliminates unwanted changes in calibration or alarm settings from
accidental touching or bumping of the keys. To further reduce the possibly of
incorrect adjustments at least two keys must be pressed in order to modify a
critical calibration or alarm set point value.

Note: The ALARM SILENCE () and BATT TEST key continue

to operate normally when the lock feature is activated.

2.1.1 Sensor Installation or Replacement

Note: The R17S oxygen sensor must be installed before the

oxygen analyzer/monitor can be operated

1. Remove the new sensor from its protective bag. Inspect the

sensor for damage or electrolyte leakage. If the sensor is
damaged, obtain a replacement. Do not use the defective sensor
as it may damage the unit.

Teledyne Analytical Instruments 13

Operation AD300/MD300

WARNING: THE SENSOR ELECTROLYTE IS CAUSTIC. DO NOT

LET IT COME IN CONTACT WITH SKIN. IF IT DOES,
FLUSH AFFECTED AREA WITH WATER. DO NOT
ATTEMPT TO OPEN OR REPAIR THE SENSOR.

2. Plug one end of the coiled cable into the jack receptacle on the

back end of the R17S sensor and secure in place with the capture
nut located at the base of the connector. See Figure 2-1.

Figure 2-1: Installing the R17S Sensor

3. Plug the other end of the coiled cable into the receptacle located on

the right side of the unit and secure it in place using the capture nut.
See Figure 2-2.

Figure 2-2: Sensor Cable Connection to Monitor

Teledyne Analytical Instruments 14

Portable Oxygen Monitor Operation

Note: When the AD/MD300 instrument is used for diffusion

sampling the plastic flow diverter must be removed from
the R17S sensor. If the sensor is used in sample mode the
diverter must be used as shown in Figure 2-3.

Figure 2-3: Mounting the Sensor in the Tee Adapter

2.1.2 Mounting

The AD/MD 300 can be mounted in several ways depending on the
optional equipment ordered at the time of purchase. See Section 1.2.

2.1.2.1 V-MOUNT ADAPTER INSTALLATION

The V-Mount Adapter consists of a matching plastic plate with
integral V-grooves that attach to the rear of the instrument.

To install V-Mount Adapter, remove the battery compartment door
by prying up the hinged latch at the bottom of the cover, then slide the
adapter plate into grooves provided in rear case. Replace the battery
compartment door and secure door latch. See Figure 2-4.

Note: The door latch is a tight fit onto the battery cover. Use a

coin to gently pry up the latch.

Teledyne Analytical Instruments 15

Operation AD300/MD300

Figure 2-4: V-Mount Adapter Installation

2.1.2.2 UNIVERSAL MOUNTING CLAMP INSTALLATION

The Universal Mounting Clamp is supplied with a 1/4-20 screw for
securing the clamp to the rear of the instrument. A threaded brass insert is
installed on the back of the instrument for this purpose. See Figure 2-5.

Figure 2-5: Brass Insert for Universal Mounting Clamp

2.1.3 Battery Installation

Note: Three “AA” alkaline batteries must be installed in the unit

before the monitor will operate. The unit must be
recalibrated whenever new batteries are installed. For
the MD300, the HI and LOW alarm set points must be
reset to the desired values.

To install the batteries:

1. Turn the unit off (if it is on).

2. Hold the instrument face down in the palm of your hand. Use

a coin to pry up the latch that secures the battery
compartment door. Remove the battery compartment door.

Teledyne Analytical Instruments 16

Portable Oxygen Monitor Operation

CAUTION: IMPROPER INSTALLATION OF THE BATTERIES

MAY RESULT IN DAMAGE TO THE UNIT AND
BATTERIES.

Note: Use alkaline batteries only. Other battery types will

produce erroneous battery test readings.

3. Install 3 ―AA‖ alkaline batteries into the holder as shown in

Figure 2-6. Each battery has its own slot. To insure proper
polarity, place the bottom (flat) or negative end of the battery
in the end of the holder marked ―–‖. Place the top (button) or
positive end of the battery in the end of the holder marked
―+‖. Do this for each battery.

Figure 2-6: Installing Batteries

4. Re-install the battery compartment door. When the unit is

first turned on the display will momentarily display all LCD
segments. During this period diagnostic tests are being
conducted to insure the circuits are functioning correctly.
The unit will activate the audible and visual alarms for about
1 second. The LCD will flash continuously indicating the
unit is in the unlocked position ready for calibration.

Note: When batteries are first installed or power is lost for any

reason the instrument defaults to the calibration mode. All
keys except the CAL and ON/Off (I/O) keys are inoperable
until a successful calibration is achieved.

5. (MD300 only) To test the batteries. Press the BATT TEST

key once. The battery display, located below the oxygen

Teledyne Analytical Instruments 17

Operation AD300/MD300

Figure 2-7: Calibration Sequence

readout display, should show a bar graph of the remaining
life to the batteries. In the case of fresh batteries, it should
illuminate all 5 segments from the left to the right end of the
bar.
(AD300 only). The bar graph indicator is on continuously
whenever the instrument is powered on.

2.1.4 Calibration

The AD/MD300 should be
calibrated before each use.

Whenever new batteries are

installed or removed for any
reason, the oxygen monitor
defaults to the calibration mode
with the LCD display flashing

00.0. Only the CAL and ON/OFF
(I/O) keys are functional at this
point. On the MD300 monitor, the
alarm set points will also need to
be reset after calibration is
completed.

Note: For first time and for

routine maintenance
calibrations, make sure
the sensor and sensor cable are installed correctly before
attempting to calibrate the instrument

To calibrate the instrument (See Figure 2-7):

1. Turn the unit on by pressing the ON/OFF (I/O) key.

2. Check the batteries by pressing the BAT key.

3. If the LCD is not flashing, press the LOCK/UNLOCK key to

unlock the keys. LCD will flash indicating changes can be
made to the settings. If the batteries have just been installed
the LCD will flash 00.0

4. As with most oxygen analyzer(s) the highest level of

accuracy is achieved when calibration is conducted using
100% oxygen. After installing the flow diverter as noted in
Section 2.1.1, insert the sensor into the plastic tee and

Teledyne Analytical Instruments 18

Portable Oxygen Monitor Operation

connect to a supply of pure dry oxygen flowing at 1-2 liters
per minute.

5. Wait about 20 seconds to insure the sample line is completely

purged with the calibration gas. Press the CAL key. The
LCD will count down from 9 to 0. During this time the
microprocessor is measuring the sensor output to determine
the gas concentration and selects the calibration range i.e.
100% or 20.9%. When the calibration is complete the LCD
will display the gas value. Press the LOCK/UNLOCK key to
save the calibration data.

Note: The AD300 and MD300 can only be calibrated using 100%

oxygen or room air 20.9%. Improper calibration or use of
other gas concentrations will activate the SENSOR

indicator. To repeat the calibration press the
LOCK/UNLOCK key and press the CAL key.

6. Remove the sensor from the oxygen supply and confirm the

LCD reads less than 22% in room air. It is not necessary for
it to read exactly 20.9%.

7. It is important to perform the calibration carefully and

thoroughly, using calibration gases that are free from
contaminates. Wait for a stable reading before locking in
calibration point. The accuracy of the instrument is only as
good as the procedure used to calibrate it.

Note: A single point air calibration is not recommended unless

the sensor can be exposed to a known source of fresh
outdoor air. Confined areas such as rooms where high
concentrations of oxygen are released may be enriched
with excess oxygen, which will introduce errors into the
calibration. Air calibration should only be used for
monitoring oxygen levels between 21% and 40% and
should never be used where a high degree of accuracy
is needed.

CAUTION: DO NOT ADJUST THE CALIBRATION SETTINGS IN

AIR AFTER THE 100% CALIBRATION, AS THIS WILL
CANCEL THE MORE ACCURATE 100%
CALIBRATION. THE 100% CALIBRATION MAY BE
REPEATED AS MANY TIMES AS DESIRED.

Teledyne Analytical Instruments 19

Operation AD300/MD300

Figure 2-8: Setting the Alarms (MD300)

8. (MD300 only) Adjust alarm set points to desired level

according to the procedures in Section 2.1.5.

9. Press the LOCK/UNLOCK key to hold settings. The unit is

now ready for use.

2.1.5 Alarms (MD300 only)

Note: Before attempting to change the alarms it is necessary to

unlock the control keys by pressing the LOCK/UNLOCK
key. When pressed the display will start flashing.

To set the alarms on the MD300 monitor (see Figure 2-8):

1. To set the HI alarm: Press the HI ALARM

SET key once. Press the UP and DOWN
arrow key until the desired value is displayed
in the lower right corner of the display. Press
lock key or proceed to LO alarm settings

Note: The HI and LO alarms may be defeated

by setting the HI alarm limit one step
above 100%. The display will blink
ALARM OFF continually in this mode.

2. To set the LO alarm, press the LO ALARM SET

key once. Press the UP and DOWN arrow key
to select a value. A built-in safety feature will
not allow you to select a LO alarm value less
than 18%. Press LOCL key to save settings.

Note: The MD300 is designed to prevent crossing of HI/LO alarm

settings. If you attempt to set the LO alarm higher than the HI
alarm, it will push the HI alarm setting up as you continue to
rise the LO alarm set point. This also applies when
attempting to set the HI alarm lower than the LO alarm.

3. To test the alarms, unlock the controls by pressing the

LOCK/UNLOCK key and then press ALARM TEST key. The
Lo alarm followed by the HI alarm will blink and the audible
visual alarm will are activated for about 1 second.

4. To silence the alarm buzzer for 115 seconds press the alarm

silence key () (flashing red indicator light).

Teledyne Analytical Instruments 20

Portable Oxygen Monitor Operation

5. To disable the alarms set the high alarm set point above 100%.

Press LOCK/UNLOCK key to save settings.

Note: When the alarm is in the OFF condition (set point above

100%) the ALARM OFF status message blinks slowly on
the LCD below the oxygen readout.

2.1.6 Output 0-1 VDC or RS232

Both the AD300 and MD300 provide signal outputs for use with
recorders and computers. The instruments are supplied standard with a
0-1 VDC output. An optional 0-1 VDC Interface Cable (P/N B-75554)
is available from Teledyne for this purpose.

To connect the analyzer to an analog recording device:

1. Insert one end of the interface cable into the output port on

the side of the instrument. See Figure 2-9.

2. Insert the other end into the analog recorder device. Make

sure the device is equipped to handle a 0-1 VDC signal.

When properly calibrated, the output signal generated by the
analyzer is linear and proportional to the oxygen concentration.

If you requested Option-B (RS 232 digital output) at the time of
purchase, a digital RS 232 signal is output from the output port shown in
Figure 2-9. Use the optional RS 232 Interface Cable (P/N B-75555)
available from Teledyne for connection to a standard RS 232 port on a
computer or other suitably equipped digital device.

Teledyne Analytical Instruments 21

Operation AD300/MD300

Figure 2-9: 0-1 VDC or RS 232 Digital Output Port

If your instrument is set for analog (0-1 VDC) output, you can
reconfigure it to use the digital output by changing a jumper on the
internal PC board.

To activate the digital output:

1. Remove the batteries and remove the five screws that hold the

case together.

2. Remove the rear case section leaving the PCB in the front half of

the case.

3. Remove jumper at position JP3 and reinstall it at position JP7.

4. Replace the rear cover and secure in place with five screws.

Install the batteries and recalibrate per Section 2.1.4.

CAUTION: RECORDER/RS232 OUTPUT SIGNAL SHOULD ONLY

BE CONNECTED TO AN EN60601-1/IEC60606-1
APPROVED DEVICE.

To reconfigure the analyzer from a digital (RS 232) output to
analog (0-1 VDC) output, use the same procedure except in step 3
remove the jumper from JP7 and replace it at JP3.

2.2 Use

2.2.1 Gas Sampling

The AD/MD300 instruments can be used to measure the oxygen
concentration in two basic modes:

Teledyne Analytical Instruments 22

Portable Oxygen Monitor Operation

From the low pressure inflator hose using the sample

adapter as shown in Figure 2-10.

Directly from the high pressure gas cylinder using the

optional DIN restrictor shown in Figure 2-11.

NOTE: Both sample modes require the use of the gas diverter

cap and tee adapter as show in Figure 2.3. Make sure you
have calibrated the unit before proceeding.

INFLATOR HOSE SAMPLING. Connect the inflator hose adapter
supplied with the unit to the tee adapter as shown in Figure 2.10. Open
the gas bottle valve and allow gas to flow for approximately 30 seconds.
When a stable reading is observed close the cylinder valve. Allow
reading to settle for a few seconds. This is the oxygen value of the
sample gas.

Figure 2-10: Low Pressure Gas Sampling

HIGH PRESSURE SAMPLING. To measure the oxygen concentration
directly from the high pressure cylinder. Install the optional DIN connector
onto the tank and insert the blue tee adapter and sensor as shown in Figure 2-

3. Slowly open the cylinder valve until you detect gas flowing. When a stable
reading is observed close the cylinder valve and allow the reading to settle for
a few seconds. This is the oxygen value of the sample gas.

CAUTION: MAKE SURE YOU DO NOT PRESSURIZE THE

SENSOR DURING CALIBRATION OR USE, AS THIS
WILL PRODUCE ERRORS IN THE READINGS.

Teledyne Analytical Instruments 23

Operation AD300/MD300

Figure 2-11: High Pressure Gas Sampling

When monitoring for oxygen in confined volumes such as a diving
bell, the flow diverter must be removed from the R17S sensor so that it
does not interfere with the rapid exchange of gases to and from the
sensing surface of the sensor.

CAUTION: FAILURE TO REMOVE THE DIVERTER IN THESE

APPLICATION AREAS WILL RESULT IN A MARKED
LOWERING OF THE RESPONSE TIME OF THE
SENSOR.

The LOCK/UNLOCK key can be used to prevent accidental
changes to the front panel key adjustments. The LOCK/UNLOCK key
acts as a toggle, pressing LOCK/UNLOCK once renders inactive all
keys except the ALARM SILENCE () and BATT TEST (MD300
only) keys. Pressing LOCK/UNLOCK a second time unlocks the
keypad.

2.3 Gas Sampling/Sensor Issues

2.3.1 Temperature

The R17S oxygen sensor adjusts for ambient temperature changes
in the range of 0–40°C (32–106°F). However, a small thermal tracking
error may be encountered when the sensor is subjected to sudden
changes in temperature. For example removing the sensor from an air
conditioned car to a hot environment. Holding the sensor in your hand

Teledyne Analytical Instruments 24

Portable Oxygen Monitor Operation

for more than a few minutes can also affect the temperature tracking
which appears as a slow drift on the LCD. No adjustments should be
made during this period since this error will correct itself in about 30
minutes.

2.3.2 Pressure

Virtually all gas sensors and monitors measure the partial pressure,
not the percentage, of the gas that they sense. The only time that these
instruments can accurately read percentages is when the total pressure
does not vary over time between calibrations and use. This is way it is
important to calibrate the AD/MD300 oxygen sensor at regular intervals.
It is recommended that the unit be calibrated prior to each use or every 8
hours.

When the sensor is connected to sample gas that is flowing under
pressure, the sensor may read high. In reality, the percentage of oxygen is
not changing; it is the total pressure that is increasing, producing a
corresponding increase in the partial pressure of oxygen. A hundred
centimeter of water pressure pulse will produce a 0.11 atmosphere, or an
11% increase in the total and therefore partial pressure of oxygen. An un­pressurized reading of 50% oxygen will increase to 55.3% if the sensor is
subjected to a pressure of 100cm H2O. The reading will rise proportionally
less for smaller pressures.

2.3.3 Humidity

Humidity does not directly affect the accuracy of the sensor's
measurement. However, when a nebulizer or other device is used to
increase moisture levels in gas mixtures, the moisture actually dilutes
the mixture. This dilution effect decreases the oxygen concentration.

For example, if an 80% oxygen gas mixture is humidified to
saturation at room temperature, the resulting gas mixture will contain
only 77.5% oxygen. Your portable oxygen monitor accurately measures
decreases in the oxygen concentration due to the dilution effects of
moisture added to gas mixtures.

As with all oxygen sensors, excessive condensation on the sensing
surface of the R17S will block the diffusion of oxygen to the sensor,
rendering it inoperative. We recommend installing the sensor on the dry
side of the breathing circuit at all times.

Teledyne Analytical Instruments 25

Operation AD300/MD300

2.3.4 Discrepancy in Readings

When a discrepancy in oxygen readings is suspected, the oxygen
analyzer readings should be verified by checking the AD/MD300 battery
condition and calibration using 100% oxygen. If the monitor can be
calibrated, the unit can be assumed to be in good working order and
capable of providing readings to specification. If, after checking the unit,
the discrepancy in oxygen readings persists, the gas being analyzed
should not be used. Further investigation should be made until the
discrepancy in readings is resolved. The troubleshooting section of this
manual may provide additional assistance in locating the problem.

Teledyne Analytical Instruments 26

Portable Oxygen Monitor Operation

2.4 Do’s and Don’ts

– DO –

Read all of the directions before using for the first time.
Calibrate before every use.
Visually inspect the sensor for leakage before each use.
Calibrate using 100% oxygen and check in air.
Check the HI and LO alarm settings prior to each use.
Test batteries regularly and replace when battery indicator shows

low battery (no bars remaining)

Make sure keys are locked by using the LOCK/UNLOCK key

feature.
Keep the unit, sensor and connections dry.
Recalibrate after replacing the batteries.
Recalibrate after replacing the sensor.
Use properly installed alkaline batteries only.
Make sure the R17S sensor is properly attached.
Remove the plastic flow diverter when analyzing non-flowing

samples.
Remove and save the plastic flow diverter when using the sensor

in non-flowing applications.
(MD300 only) Perform an alarm test before each use (press the

ALARM TEST key).

– DON’T –

Use this monitor if you suspect any malfunction.
Do not use the instrument if the oxygen readings are drifting.
Use the instrument in the presence of flammable liquids or gases.
Use anything but alkaline batteries.

Teledyne Analytical Instruments 27

Operation AD300/MD300

Freeze the sensor or instrument.
Open or try to repair a leaking or broken sensor.
Immerse the unit or sensor in any liquid.
Pass hot or cold gas mixtures over the sensor.
Adjust the reading in air after 100% calibration
Use cleaning agents or liquids in the cable receptacles or around

the battery compartment.
Store the unit in hot or humid environment.
Expose the LCD to excessive sunlight.

Teledyne Analytical Instruments 28

Portable Oxygen Monitor Service Manual

Service Manual

3.1 General Service Information

The Teledyne Model AD300 and MD300 series of portable oxygen
monitors are designed to be robust yet compact in size. In order to
achieve maximum reliability in a microprocessor-based instrument, a
single PC board is used which relies exclusively on surface mount
technology. Without access to specialized probes and test equipment,
troubleshooting and repair of circuit board components are not feasible.
A factory replacement of the entire PC board is more cost effective than
a field repair of an individual component

With the exception of replacing the sensor or batteries there are no
user-serviceable components inside the unit. There are no potentiometers or
other adjustments to be made within this instrument. If a problem arises
with either of these models that cannot be corrected by recalibration,
changing the batteries, or replacing the sensor as described elsewhere in
this manual, the unit must be sent back to the factory for repair or
replacement. See Section 3.9 for instructions on obtaining a Return
Merchandise Authorization (RMA) number before sending a unit back
to Teledyne for repair.

3.2 Overall Maintenance

The AD/MD 300 series of instruments require very little
maintenance, other than calibration, checking and changing the batteries
and sensor, and cleaning the plastic housing. Occasional cleaning of the
plastic surface can be done with isopropyl alcohol. Should any part of
the instrument malfunction or fail to perform, the unit should be
removed from service. There are no user-serviceable components within
the instrument.

3.3 Battery Maintenance

DO: Test batteries regularly (replace immediately when all 5 bars

are missing).

DO: Always use alkaline batteries.

Teledyne Analytical Instruments 29

Service Manual AD300/MD300

DO: Recalibrate after replacing batteries.

The MD300 instrument incorporates a battery test feature that
indicates the approximate amount of useful life remaining on the set of
batteries. Excessive alarm activation will wear down the battery faster
than usual. The AD300 instrument continuously displays the battery
status bar graph. There is no BATT TEST key on the AD300.

The minimum detectable change in battery voltage corresponds to
an increment of about 50 hours, meaning that the battery voltage reading
may not change for several hours at a time.

If the monitor is not used for a period of 30 days or more, the
batteries should be removed prior to storage.

3.4 Sensor Maintenance

DO: check the sensor for damage or leaks before use.

DO: recalibrate after replacing the sensor.

DON’T: immerse the R17S sensor in liquid.

DON’T freeze the R17S sensor.

DON’T: open or try to repair the sensor.

Before every use, the sensor, cable and connections should be
checked. Check the sensor for leaks and condensation. Check the cable
for splitting or cracked insulation. Make sure the connections are tight
and dry.

In the event that the sensor has been damaged, consult the Material
Safety Data Sheet available from the factory or online at www.teledyne­ai.com for handling guidelines.

3.5 Gas Sampling

3.5.1 Discrepancy in Readings

The AD300/MD300 instrument should be used to measure the
oxygen concentration exiting gas cylinder or another or life support
system. When a discrepancy in oxygen readings is detected, the oxygen
analyzer readings should be verified by checking the AD/MD300 battery
condition and calibration using 100% oxygen. If the monitor can be
calibrated, the unit can be assumed to be in good working order and
capable of providing readings to specification. If, after reinstalling the

Teledyne Analytical Instruments 30

Portable Oxygen Monitor Service Manual

Symptom

Why

What To Do

New sensor responds
slow or drifts.

If the sensor is new and
was just removed from
its sealed bag it may
need to run for several
hours.

A) Wait 30 minutes and

recalibrate.

Sensor will not read below
22 % after calibration in
100% O2.

Calibration in 100% was
invalid or the room air is
contaminated with
excess oxygen.

A) Recalibrate using

dry gas making sure
the reading
stabilizes before
making any
adjustments.

B) Make sure that at

least 6" (30 cm.) of
tubing is attached to
the exhaust side of
the tee adapter to
prevent back filling.
O2 flow rate should
not exceed 5 l/min.

C) Oxygen

concentration at the
sensor is significantly

unit, the discrepancy in oxygen readings persists, the problem is most
likely elsewhere. Further investigation should be made until the
discrepancy in readings is resolved. The troubleshooting section of this
manual may provide additional assistance in locating the problem.

Note: The MSDS on this material is available upon request

through the Teledyne Environmental, Health and Safety
Coordinator at [phone] or can be viewed and
downloaded from our web site at www.teledyne-ai.com.

3.6 Troubleshooting

The AD300 and MD300 oxygen monitors provide a variety of built-in
safety features that prevent its use when a fault is detected. When a unit
displays the message √ SENSOR and sounds the audible and visual alarm
continuously, it is an indication of a faulty connection between the sensor and
the unit or an expired or faulty sensor. To determine where the difficulty lies,
refer to the following guidelines in Table 3-1.

Table 3-1 Troubleshooting

Teledyne Analytical Instruments 31

Service Manual AD300/MD300

Symptom

Why

What To Do

higher than 21%.
Take the instrument
to a well-ventilated
area and check the
reading again.

D) Try calibrating with a

known good sensor;
if this fails, see
symptom "Reading
drifts over 2–3%..."

The display is flashing

√ SENSOR

The unit has detected a
fault in the signal from
the sensor.

Sensor has expired.
The sensor has been

exposed to a gas
containing little or no
oxygen.

A) Check sensor cable

connections and
make sure they are
completely inserted
into the mating
connector and the
capture nut is firmly
in place.

B) Expose the sensor

in 100% O2 and
check calibration.

C) The sensor output

has fallen to a level
where it is no longer
usable. Replace
sensor.

The oxygen reading
fluctuates or appears to
be incorrect.

Like all O2 sensors, the
R17S detects the
changes in the partial
pressure of O2.

A) During calibration,

make sure there is
no restrictions on
exhaust side of
sensor. If the reading
changes with flow,
the sensor is
pressurized or there
may be a leak in the
system.

B) If a high degree of

accuracy is desired,
or the concentration
of O2 is in excess of
40%, calibration with
100% is recom­mended.

Teledyne Analytical Instruments 32

Portable Oxygen Monitor Service Manual

Symptom

Why

What To Do

The unit has stopped
working and the LCD is
displaying alphanumeric
figures.

The AD300/MD300
instruments are equipped
with an electronic "watch
dog," which monitors the
circuitry within the unit for
potential faults and
renders the unit
inoperable until the
condition is corrected.
(See Watch dog section
below)

Several conditions can
activate the "watch dog."
Dropping the unit, poor
battery connections, and
radio frequency
interference are the
most common causes.
See the watch dog
section for additional
information

A) Disconnect the

batteries and inspect
the contacts for
corrosion. Reconnect
the batteries. If the
unit functions
properly, calibrate the
unit and reset the
alarm values.

B) Try a new set of

batteries.

C) Increase the distance

between the unit and
any source of radio
frequency
interference. The
sensor cable is a
prime source of
pickup as it can act
like an antenna.
Relocate the sensor
cable and if possible
change its coiled
length to ―de-tune‖ its
antenna effect.
Placing the cable in a
different position may
also help.

Alarm sounds/flashes
continuously.

A) (MD300) Readings

are outside alarm
limits.

A) Adjust high and low

alarm setting to be
above and below O2
value being
displayed.

No display.

A) Batteries expired.
B) Bad battery

connection.

A) Check/replace

batteries.

B) Check battery

connections.

C) Calibrate.

Keys inoperable/cannot
turn unit off

The LOCK/UNLOCK key

is activated which is
preventing key operation

A) Press

LOCK/UNLOCK key
once. LCD will flash
indicating keys are
active.

Teledyne Analytical Instruments 33

Service Manual AD300/MD300

Symptom

Why

What To Do

Cannot adjust
calibration or alarm
settings

Critical settings require

two keys be pressed in a
specific order.

LOCK/UNLOCK key is

active

A) If display is not

flashing press lock
key once to activate
keys. Press desired
function followed by
the Up and Down
key.

Note: In the event that none of these procedures produce desired

results, remove the batteries and return the unit to Teledyne for
repair.

3.7 Watchdog

The AD300/MD300 is equipped with a watchdog circuit that
continuously monitors the electronics for proper operation. If the watchdog
detects a failure, one of the following codes will appear on the LCD.

The error codes can appear on the LCD when batteries are first
installed, during normal operation or if the unit is subjected to extreme
shock. In some cases an additional digit is used in the error code to
supply additional information. For example, the error code 6 and 7 are
followed by another digit listed as (N) in Table 3.2. The error code 65
would indicate that a key is stuck and this key is the Silence key.

In addition to supplying visual error codes, the audio device will
beep a number of times to indicate the general error in case the display is
not functional.

NOTE: To reset the watchdog error code. Remove one battery for

5 seconds and replace. If the error persists contact your
locale representative or Teledyne for assistance.

Teledyne Analytical Instruments 34

Portable Oxygen Monitor Service Manual

Error Code

Audio Beeps

Error

Indeterminate

2

The watchdog timer has timed out indicating a
serious software error

30

3

Analog output is different from the expected value.
May indicate a shorted or over-loaded analog
output or a failure of the analog to digital converter
or digital to analog converter circuit.

50

5

The ADC circuit failed during POST.

6 (5)

6

(There is no
indication of
which key is
stuck)

A stuck key has been detected. The second digit,
in this example (5), on the display shows which
key is stuck:

0 - Low Alarm
1 - Batt
2 - Cal
3 - Up
4 - Down
5 - Silence
6 - High Alarm
7 - Alarm Test
8 - Key Lock

7(2)

7

(There is no
indication of
the type of
DAC failure)

A failure has occurred during the automatic
calibration of the digital to analog converter (DAC)
circuit. The second digit, in this example (2),
shows the type of digital to analog failure.

0 - Measurement
1 - High Test
2 - Low Test
3 - Offset Cal
4 - Gain Cal

Table 3-2 Error Codes

Teledyne Analytical Instruments 35

Service Manual AD300/MD300

3.8 Other Problems with the Instrument

Most other problems arise from either mechanical damage from the
instrument falling from a bench or table, or electronic component
failure. In these units, repair or troubleshooting the PCB or individual
component on the board is not feasible. It requires specialized test
equipment and probes not generally available to the public. Under most
circumstances a replacement of the entire PC Board is recommended.
The instrument must be returned to the factory for PCB installation.

Occasionally, depending on the environment of use, keys can
become stuck or function erratically due to contamination. Use a mild
non-abrasive cleaner solution to periodically clean the keypad and
screen. An aerosol jet spray of the type commonly used to clean
computer keyboards can be used to dislodge dirt and accumulations
from the keypad.

The Error Code Table (Table 3-2) includes a description of certain fault
codes which are diagnostic of some common (usually electronic) problem
with the instrument. Some of these codes refer to specific components on the
PCB that are problematic or have failed. These codes are useful in reporting
a problem with your instrument to Teledyne Customer Service. If an error
code is indicated on your monitor record the number and report it to the
Customer Service Department at the address below.

3.9 Return Authorization for Service

For any service beyond sensor and battery replacement, the
instrument must be returned to the factory. A return merchandise
authorization (RMA) number must be obtained from Teledyne
Analytical Instruments prior to returning an instrument for service. You
can request a RMA number via email by contacting us at:

[e-mail]

You can also contact us at the address below.

Customer Service Department

TELEDYNE Analytical Instruments

16830 Chestnut Street
City of Industry, CA 91749-1580 USA

Phone [phone], Fax [phone]
Or via the web at: www.teledyne-ai.com

Teledyne Analytical Instruments 36

Portable Oxygen Monitor Appendix

Appendix

A.1 Specifications

Range: 0-100% Oxygen
Accuracy: +2% of full scale (at constant temperature

and pressure)

Response Time: 90% in less than 8 seconds at 25 °C
Battery Life: Approximately 2000 hr. continuous use in

a non-alarm condition

System Power: 3 AA alkaline batteries.
Sensor Type: Class R17S
Expected Life: 36 months in air
Dimensions: 2.5" W × 1.25" D × 4.5" H (66 mm x 33-

mm × 111.5 mm)

Sensor Cable: Retracted: 2 ft / Extended: 10 ft.
Storage Temp. 10-30 °C (continuous), 5-50 °C

(Intermittent)

Operating Temp: 0-40 °C

Alarm ranges: HI alarm: 19 to 100 Percent
LO alarm: 18 to 99 %

Alarm accuracy: Alarm thresholds are digitally stored and

alarm affectivity is digitally compared
against the value calculated by the
microprocessor. Hence, the accuracy of the
alarms is the same as the accuracy of the unit
as specified above.

Teledyne Analytical Instruments 37

Appendix AD300/MD300

A.2 Spare Parts List

QTY PART NO DESCRIPTION

1 C72144-R17S Micro-Fuel Cell R17S
1 B50057 R17S flow diverter
1 A268 Tee adapter (22 mm)
1 CP 2367 22 mm female tube adapter
1 CP 2368 22 mm male tube adapter
1 B75401 Inflator sample adapter assembly
3 B99 ―AA‖ size alkaline battery
1 C74721 Sensor cable assembly

A.3 Optional Accessories

1 A585 DIN 300 flow Restrictor
1 CP2345 Universal Mounting Clamp
1 CP2344 ―V‖ mount Pole Clamp
1 B647 ―V‖ mount Wall Adapter
1 B-75554 0-1 VDC Interface Cable
1 B-75555 RS 232 Interface Cable

____________________

Note: Orders for replacement parts should include the part

number (if available) and the model and serial number of
the instrument for which the parts are intended.

Teledyne Analytical Instruments 38

Portable Oxygen Monitor Appendix

Orders should be sent to:

TELEDYNE Analytical Instruments

16830 Chestnut Street
City of Industry, CA 91749-1580

Phone [phone], Fax [phone]
Web: www.teledyne-ai.com

Or your local representative.

Teledyne Analytical Instruments 39