RKI Instruments CO-01 User manual

www.rkiinstruments.com
01 Series
Operator’s Manual
Part Number: 71-0093RK
Revision: A
Released: 2/2/11

01 Series Operator’s Manual
WARNING
Read and understand this instruction manual
before operating instrument. Improper use of the
gas monitor could result in bodily harm or death.
Periodic calibration and maintenance of the gas
monitor is essential for proper operation and cor-
rect readings. Please calibrate and maintain this
instrument regularly! Frequency of calibration
depends upon the type of use you have and the
sensor types. Typical calibration frequencies for
most applications are between 1 and 3 months,
but can be required more often or less often
based on your usage.

01Series Operator’s Manual Warranty
Warranty RKI Instruments, Inc. warrants the 01 Series Single Gas Monitor sold by us
to be free from defects in materials, workmanship, and performance for a
period of two (2) years from the date of shipment from RKI Instruments,
Inc. This includes the instrument and the original sensor. Replacement
parts are warranted for one (1) year from the date of their shipment from
RKI Instruments, Inc. Any parts found defective within their warranty period
will be repaired or replaced, at our option, free of charge. This warranty
does not apply to those items, which by their nature, are subject to
deterioration or consumption in normal service, and which must be
cleaned, repaired, or replaced on a routine basis. Examples of such items
are as follows:
Warranty is voided by abuse including mechanical damage, alteration,
rough handling, or repair procedures not in accordance with the instruction
manual. This warranty indicates the full extent of our liability, and we are
not responsible for removal or replacement costs, local repair costs,
transportation costs, or contingent expenses incurred without our prior
approval.
THIS WARRANTY IS EXPRESSLY IN LIEU OF ANY AND ALL OTHER WARRANTIES
AND REPRESENTATIONS, EXPRESSED OR IMPLIED, AND ALL OTHER OBLIGATIONS
OR LIABILITIES ON THE PART OF RKI INSTRUMENTS, INC. INCLUDING BUT NOT
LIMITED TO THE WARRANTY OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE. INNO EVENT SHALL RKI INSTRUMENTS, INC. BE LIABLE
FOR INDIRECT, INCIDENTAL, OR CONSEQUENTIAL LOSS OR DAMAGE OF ANY KIND
CONNECTED WITH THE USE OF ITS PRODUCTS OR FAILURE OF ITS PRODUCTS TO
FUNCTION OR OPERATE PROPERLY.
This warranty covers instruments and parts sold to users only by
authorized distributors, dealers, and representatives as appointed by RKI
Instruments, Inc.
We do not assume indemnification for any accident or damage caused by
the operation of this gas monitor and our warranty is limited to replacement
of parts or our complete goods.
Absorbent cartridges
Filter elements, disks, or sheets
Pump diaphragms and valves

Table of Contents 01 Series Operator’s Manual
Table of Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Protective Rubber Boots. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Alligator & Belt Clips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Membrane Retainer/Sensor Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Charcoal Filter Disk in CO-01 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Sensor Retainer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
LCD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Control Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Printed Circuit Boards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Alarm Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Buzzer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Vibrator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Start Up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Start-up Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Performing a Fresh Air Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Turning Off the 01 Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Measuring Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Displaying the Peak, STEL, and TWA (CO-01 and HS-01) . . . . . . . . . . . . . . . . 11
Displaying the Min and Max (OX-01) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Alarm Points. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Displaying and Adjusting the Alarm Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Calibration Frequency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Setting the Fresh Air Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Setting the Span Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

01Series Operator’s Manual Table of Contents
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Replacing the Batteries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Replacing the Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Replacing the Sensor Cover and Charcoal Filter . . . . . . . . . . . . . . . . . . . . . . . . 25
Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
WARNING: Understand this manual before operating the 01 Series.
Substitution of components may impair intrinsic safety.
To prevent ignition of a hazardous atmosphere, batteries
must only be changed in an area known to be
nonhazardous. This unit has not been tested in an
oxygen enriched atmosphere (above 21%).

1 • Introduction 01 Series Operator’s Manual
Introduction
Using an advanced microprocessor controlled detection system, the 01
Series Personal Single Gas Monitor detects the presence of either carbon
monoxide (CO), hydrogen sulfide (H2S), or oxygen (O2). The 01 Series’s
compact size and easy-to-use design makes it ideally suited for a wide
range of applications, including sewage treatment plants, tunnels,
hazardous waste sites, petrochemical facilities, oil fields, mines, and
chemical plants. The 01 Series is even small enough to be placed
conveniently in a pocket. The 01 Series offers the following features:
• Compact design
• Fast, accurate response with digital liquid crystal display (LCD)
• Visual, audible, and vibration alarms
• Microprocessor control for reliability, ease of use, and advanced
capabilities
• Peak, STEL, and TWA indication for CO-01& HS-01
• Minimum and maximum indication for OX-01
• Over range alarm
• Gas, battery, sensor failure, and system failure alarms
• Over 3,000 hours operation on one set of alkaline batteries
• CSA certified for intrinsic safety in Class I, Division I, Groups A, B, C,
and D hazardous atmospheres
• Low temperature operation down to -40 °C with the HS-01S
WARNING: The 01 Series detects oxygen deficiency and elevated
levels of oxygen, carbon monoxide, and hydrogen
sulfide, all of which can be dangerous or life threatening.
When using the 01 Series, you must follow the
instructions and warnings in this manual to assure
proper and safe operation of the unit and to minimize the
risk of personal injury. Be sure to maintain and
periodically calibrate the 01 Series as described in this
manual.

01Series Operator’s Manual Specifications • 2
Specifications
Table 1: 01 Series Specifications
CO-01 HS-01/HS-01S OX-01
Target Gas Carbon Monoxide
(CO) Hydrogen Sulfide (H2S) Oxygen (O2)
Detection Range 0 to 500 ppm 0 to 100.0 ppm 0 to 40.0% vol.
Display Increment 1 ppm 0.5 ppm 0.1% vol.
Detection
Principle Electro Chemical Electro Chemical Galvanic Cell
Alarm Points Low 25 ppm
High 50 ppm
TWA 25 ppm
STEL 200 ppm
Low 10.0 ppm
High 30.0 ppm
TWA 10.0 ppm
STEL 15.0 ppm
Low 19.5% vol.
(decreasing)
High 23.5% vol.
(increasing)
Sampling Method Diffusion Diffusion Diffusion
Response Time T90 in 30 seconds T90 in 30 seconds T90 in 20 seconds
Accuracy ±5% of reading or
± 5 ppm CO
(whichever is
greater)
±5% of reading or
± 2 ppm H2S
(whichever is
greater)
± 0.5% O2
Indication 7-Segment Digital LCD
Safety/Regulatory
C US
186718
CSA classified, “C/US”, as Intrinsically Safe. Exia. Class I,
Groups A, B, C, & D. Temperature Code T3.
Power Two AAA size Alkaline Batteries Standard, Duracell MN2400
or PC2400, Eveready Energizer E92 or EN92
Continuous
Operating Hours • At 25 °C, All Models: Over 3,000 Hours, No Alarms or Backlighing
• At -40 °C, HS-01S: 1,500 Hours, No Alarms or Backlighting
Case High-impact Plastic, Dust and Weather Proof
Standard
Accessories • Wrist Strap
• Rubber protective boots

3 • Specifications 01 Series Operator’s Manual
Optional
Accessories • Calibration Adapter
• Calibration Kit
• Alligator Clip
• Belt Clip
Dimensions and
Weight 1.4” (35mm) W x 4.1” (104mm) H x 0.8” (20mm) D; 3.5 oz. (100 g)
OperatingTemp.&
Humidity • CO/HS/OX-01: -20°C to +50°C, below 90% RH (non
condensing)
• HS-01S: -40°C to +50°C, below 90% RH (non
condensing)
Table 1: 01 Series Specifications
CO-01 HS-01/HS-01S OX-01

01Series Operator’s Manual Description • 4
Description
This section describes the components of the 01 Series. These
components include the 01 Series’ protective rubber boots, case,
membrane retainer and filter disks, sensor retainer, sensor, LCD, control
buttons, printed circuit boards, alarm lights, buzzer, vibrator, and batteries.
LCD
Control Buttons
Alarm Lights
Buzzer Opening Membrane
Retainer Sensor
Retainer
Battery Cover
Battery Charging
Contacts
POWER
MODE
AIR
CO-01
CO
Sensor En
d
Boot
Battery End
Boot
Threaded
Inserts
Figure 1: Components of the 01 Series

5 • Description 01 Series Operator’s Manual
Protective Rubber Boots
A protective rubber boot is installed over each end of the 01 Series. The
sensor end boot fits over the sensor cover end of the 01 Series and the
battery end boot fits over the battery cover end of the 01 Series.
Case
The 01 Series’ sturdy, high-impact plastic case is blue in color. The case is
suitable for use in many environmental conditions, indoors and out. The
unit is dust proof and weather resistant.
The front of the case has an LCD (liquid crystal display) that shows various
readings, which are described under “LCD” in this section. To the left of the
LCD is an alarm light. Below the LCD are two black control buttons. The left
button is labeled “POWER/MODE” and the right button is labeled “AIR”.
On top of the case and to the left is the 01 Series’s buzzer, which is located
inside the unit. To the right of the buzzer is the sensor. The sensor is held in
place by the sensor retainer (the top of the case for the 01 Series) and two
screws. The sensor is protected from dirt and moisture by the sensor cover.
The sensor cover is secured by a membrane retainer and a single screw. In
the case of the CO-01, a charcoal filter is provided under the sensor cover
to protect the CO sensor from hydrogen sulfide and certain hydrocarbons.
To the left of the sensor and below the buzzer, is a second alarm light,
which is also visible from the front of the case.
The battery compartment is located on the bottom of the case. Access to
the compartment is accomplished by turning the captive battery cover
screw counterclockwise and by removing the battery compartment door.
There are two threaded holes on the back of the case. These are used to
mount the optional alligator clip or belt clip.
Toward the bottom of the back are two battery charging contacts. These
contacts are used to charge a Ni-cad battery pack which is available.
Consult RKI Instruments, Inc. for information about this option.
The wrist strap connects to the back of the case on the left side, near the
top of the unit.

01Series Operator’s Manual Description • 6
Alligator and Belt Clips
The 01 Series is available with two types of clips, the alligator clip and the
belt clip. Both are illustrated in Figure 2 below.
The alligator clip can be used to attach the 01 Series to clothing or a belt.
Teeth in the clip’s jaws prevent the unit from slipping off. The belt clip is
used to easily clip the 01 Series on a belt.
Membrane Retainer/Sensor Cover
The membrane retainer is held in place by a single Phillips screw. Beneath
the membrane retainer is a paper-like filter disk, the sensor cover. The
sensor cover protects the sensor from dirt and moisture.
The sensor cover fits into a recessed area and is held in place by the
membrane retainer. The sensor cover should be inspected periodically and
replaced if contaminated by dirt or moisture. Refer to the Maintenance
section for sensor cover replacement instructions.
Charcoal Filter Disk in CO-01
The CO-01 includes a charcoal filter disk which is located in a recessed
area beneath the sensor cover. The charcoal filter disk removes gases
from the sampled air that will cause a response on the CO sensor such as
H2S and certain hydrocarbons. If false or elevated CO readings are
Alligator Clip
Belt Clip
Figure 2: Alligator & Belt Clips

7 • Description 01 Series Operator’s Manual
noticed, especially in the presence of H2S, change the charcoal filter disk
(see the Maintenance section for instructions).
Sensor Retainer
The sensor retainer holds the sensor in place. It is attached to the top of the
case by two Phillips screws. The sensor retainer also covers the buzzer.
Should the sensor require replacement, refer to the Maintenance section
for sensor replacement instructions. The buzzer, however, is not field
replaceable.
The sensor retainer has a single diffusion port through which ambient air
reaches the sensor. Recessed areas in the sensor retainer accept the
charcoal filter disks (CO-01 only) and the sensor cover. The membrane
retainer is installed to the top of the sensor retainer with a single Phillips
screw.
Sensor
The 01 Series uses either an oxygen, CO, or H2S sensor. The sensor is
protected by the white sensor cover which is held in place by the
membrane retainer. The sensor cover allowsambient air to diffuse past it to
the sensor. The three sensors used in the three 01 Series models use
different detection principles as described below.
Oxygen Sensor
The oxygen sensor is a galvanic type of sensor. A membrane covers the
cell and allows gas to diffuse into the cell at a rate proportional to the partial
pressure of oxygen. The oxygen reacts in the cell and produces a voltage
proportional to the concentration of oxygen. The voltage is measured by
the 01 Series’ circuitry, converted to a measurement of gas concentration,
and displayed on the LCD.
CO and H2S Sensors
The CO and H2S sensors are electrochemical sensors that consist of two
precious metal electrodes in an acid electrolyte. A gas permeable
membrane covers the sensor face and allows gas to diffuse into the
electrolyte. The gas reacts in the sensor and produces a current
proportional to the concentration of the target gas. The current is amplified
by the 01 Series’ circuitry, converted to a measurement of gas
concentration, and displayed on the LCD.
LCD
The LCD is visible through the front of the case. When the 01 Series is in
Measuring Mode, the target gas concentration, battery condition, and
alarm indications are displayed on the LCD. Various other items are
displayed when the LCD is in other modes, such as Calibration Mode.

01Series Operator’s Manual Description • 8
When either of the two control buttons are pressed, the LCD backlight
comes on for 20 seconds.
Control Buttons
Below the LCD are two control buttons: POWER/MODE and AIR. The
POWER/MODE button turns the 01 Series on and off. The functions
performed by the control buttons are summarized in the following table:
Printed Circuit Boards
The primary function of the 01 Series’s printed circuit boards is to amplify
the signal sent to them from the sensor, convert the signal to a meaningful
measurement of gas concentration, display the gas concentration on the
LCD, store STEL, TWA, and peak gas readings, and activate the alarm
circuit if an alarm point has been reached. They monitor battery level,
battery failure, and sensor failure. They also control various operating
modes of the unit.
NOTE: The printed circuit boards contain no user serviceable parts.
Table 2: 01 Series Control Buttons
Button Function
POWER/MODE
• Turns the unit on and off.
• Turns the LCD back light on.
• Displays STEL and TWA readings (HS-01 & CO-
01).
• Displays peak readings (high for HS-01& CO-
01and low & high for OX-01).
• Resets the alarm circuit (gas alarms).
• Enters Calibration Mode with the AIR button.
• Enters Alarm Adjustment Mode with the AIR
button.
AIR
• Turns the LCD back light on.
• Adjusts LCD readings when the fresh air
adjustment is performed.
• Enters Calibration Mode with the POWER/MODE
button.
• Enters Alarm Adjustment Mode with the POWER/
MODE button.
• Increases settings when the unit is in Alarm
Adjustment Mode or Calibration Mode.

9 • Description 01 Series Operator’s Manual
Alarm Lights
The 01 Series has two red LED alarm lights. They alert you to gas, low
battery, and sensor failure alarms. The smaller of the two lights is square,
has a frosted plastic cover, and is located at the top of the unit to the left of
the membrane retainer. The larger alarm light is rectangular in shape, has
a diamond-grid pattern etched into the plastic cover, and is located to the
left of the LCD on the front of the case.
Buzzer
A solid-state electronic buzzer is mounted inside the 01 Series. An opening
in the sensor retainer on top of the case allows the buzzer’s sound to
emanate from the case. The buzzer sounds for gas alarms, unit
malfunctions, and dead battery alarm. It also serves as an indicator during
normal use of the various LCD display options.
Vibrator
A vibrating motor (vibrator) is mounted inside the 01 Series. The vibrator
vibrates momentarily during the power-up sequence and for gas alarms.
Batteries
Two AAA-size alkaline batteries run the 01 Series. At 25°C the alkaline
batteries last at least 3,000 hours. The battery icon on the LCD shows
remaining battery life.
When the 01 Series detects low battery voltage, a low battery warning is
activated. When battery voltage is too low for normal operation, the 01
Series sounds a dead battery alarm.
The alkaline batteries can be replaced by removing the battery door at the
bottom of the case. Turn the captive battery cover screw counterclockwise
to release the door.
WARNING: To prevent ignition of a hazardous atmosphere, batteries
must only be changed in an area known to be
nonhazardous.
A Ni-cad battery pack and charger are available. Contact RKI Instruments,
Inc. for information about this option.

01Series Operator’s Manual Start Up • 10
Start Up This section explains how to start up the 01 Series and to get it ready for
operation.
Start-up Procedure
1. Press and hold the POWER/MODE button for three seconds to turn on
the 01 Series.
For several seconds, all elements of the LCD display and the LCD
backlight turn on. The vibrator activates briefly, and it then shuts off.
The alarm lights flash on and the buzzer sounds, and then they both
turn off.
2. The 01 Series then displays the target gas (H2S, CO, or O2) before
displaying the battery voltage. The buzzer sounds again after the
battery voltage is displayed.
CAUTION: If the unit gives a low battery warning or dead battery alarm,
change the alkaline batteries before using the unit.
3. The sensor inside the 01 Series begins operating and the concentration
of the target gas is displayed on the LCD. The 01 Series is now in
Measuring Mode. The target gas concentration is displayed. The
backlight turns off after 20 seconds.
Performing a Fresh Air Adjustment
Before using the 01 Series, set the fresh air reading. Performing this
adjustment ensures accurate gas readings in the monitoring environment.
1. Find a fresh air environment of normal oxygen content (20.9%) that is
free of toxic or combustible gases.
2. With the unit on and in Measuring Mode, press and hold the AIR button.
The LCD displays “hold” prompting you to hold the AIR button.
3. Release the AIR button when the LCD displays “AdJ”. The unit will set
the reading to 0 ppm (20.9% for the OX-01) and return to Measuring
Mode.
Turning Off the 01 Series
1. Press and hold the POWER/MODE button for about five seconds to
turn off the unit. The buzzer will sound while the POWER/MODE button
is being pressed before the unit turns off.
2. Release the button when the LCD is blank. The unit is off.

11 • Operation 01 Series Operator’s Manual
Operation
This section describes the normal operation of the 01 Series in Measuring
Mode. It explains how the unit can be used to display peak, STEL, and
TWA readings for the HS-01 and CO-01, and minimum and maximum
readings for the OX-01. It also covers alarm indications.
Measuring Mode
To put the 01 Series in Measuring Mode, assuming the unit is off, press and
hold the POWER/MODE button for three seconds.
Before continuing, it is advisable to perform a fresh-air adjustment in a
fresh-air environment. Making this adjustment ensures accurate gas
readings in the monitoring environment. Refer to “Start Up” for more
information.
In Measuring Mode, the battery level and target gas concentration are
displayed on the LCD. The battery icon has four bars visible when the
batteries have a full charge. As the battery charge decreases, the bars will
gradually disappear, one by one.
The target gas concentration is displayed below the battery icon. On the
CO-01, CO is displayed in parts per million (ppm). On the HS-01, H2S is
displayed in ppm. On the OX-01, oxygen is displayed as volume percent
Displaying the Peak, STEL, and TWA (CO-01 & HS-01)
You can display the Peak, STEL, and TWA readings on the CO-01 and
HS-01 when the 01 Series is in Measuring Mode using the POWER/MODE
button. STEL is an acronym for short-term exposure limit, and it is the
average reading of the target gas (H2S or CO) during the last 15 minutes.
TWA is an acronym for time-weighted average, and it is the average
reading for the target gas (H2S or CO) during the last eight (8) hours. If
eight (8) hours has not elapsed since the unit was turned on, the TWA is
still calculated over eight hours, with the missing time assigned a zero (0)
value for the readings. Similarly, if the unit has not been on for 15 minutes,
the missing time is assigned a 0 value and the STEL is calculated over 15
minutes. The Peak, STEL, and TWA readings are cleared when the unit is
turned off.
0.0
Battery level
Gas concentration
Figure 3: LCD in Measuring Mode
ppm

01Series Operator’s Manual Operation • 12
1. The unit must be in Measuring Mode. The current gas concentration
should be displayed on the LCD.
2. Press and release the POWER/MODE button to enter Peak Gas
Display Mode. The LCD backlight will activate and the LCD will display
the peak gas reading. A small peak symbol is displayed in the upper left
corner of the LCD.
3. Press and release the POWER/MODE button again to enter STEL
Display Mode. This will display the STEL reading. The word “STEL” is
displayed in the middle of the LCD above the reading.
4. Press and release the POWER/MODE button again to enter TWA
Display Mode. This will display the TWA reading. The word “TWA” is
displayed in the middle of the LCD above the reading.
5. Press and release the POWER/MODE button once again to return the
unit to Measuring Mode.
NOTE: If you do not press a button for 20 seconds while displaying the
peak gas reading, the unit will return to Measuring Mode
automatically and the backlight will turn off.
Displaying the Min and Max (OX-01)
You can display the minimum (Min) and maximum (Max) readings on the
OX-01 when the it is in Measuring Mode using the POWER/MODE button.
The Min and Max readings are cleared when the unit is turned off.
1. Make sure the OX-01 is in Measuring Mode. The oxygen concentration
should be displayed on the LCD.
2. Press and release the POWER/MODE button to enter Min Display
Mode. This will activate the LCD backlight and display the Min reading.
A small Min symbol is displayed in the upper left corner of the LCD.
3. Press and release the POWER/MODE button again to enter Max
Display Mode. This will display the Max reading. A small Max symbol is
displayed in the upper left corner of the LCD.
4. Press and release the POWER/MODE button once again to return to
Measuring Mode.
NOTE: If you do not press a button for 20 seconds while displaying the
Min or Max readings, the unit will return to Measuring Mode
automatically and the backlight will turn off.

13 • Operation 01 Series Operator’s Manual
Alarms
This section covers alarm indications. It also tells you how to reset the 01
Series after an alarm has occurred and how to respond to an alarm
condition.
Alarm Indications
The 01 Series will sound an alarm, flash its alarm lights, and vibrate when
the target gas concentration rises above the low alarm point. The 01 Series
also sounds an alarm, flashes its alarm lights, and vibrates when the high
alarm point is reached. In addition, the 01 Series also has a low battery
warning, a dead battery alarm, an over range alarm, a sensor failure alarm,
and a system failure alarm. See Table 3 below for a description of each
alarm indication.
Table 3: Alarm Types and Indications
Alarm Type LCD Indications Other Indications
Low Alarm
Concentration of gas
rises above the low
alarm point, or for the
OX-01, falls below the
low alarm point.
• Gas reading
flashes.
• Back light turns on.
• Pulsingtoneoccurs
once per second.
• Unit vibrates once
per second.
• Alarm lights flash
once per second.
High Alarm
Concentration of gas
rises above the high
alarm point.
• Gas reading
flashes.
• Back light turns on.
• Pulsingtoneoccurs
twice per second.
• Unit vibrates twice
per second.
• Alarm light flashes
twice per second.
TWA or STEL
(CO-01 & HS-01 Only)
Concentration of CO
or H2S risesabovethe
TWA or STEL alarm
point.
• Back light turns on.
• Gas reading
flashes.
•TWA or STEL
blinks to the left of
the battery icon.
• If the unit is in both
TWA alarm and
STEL alarm, both
TWA and STEL will
be displayed.
• Pulsing tone once
per second.
• Unit vibrates once
per second.
• Alarm light flashes
once per second.

01Series Operator’s Manual Operation • 14
Resetting Gas Alarms
To reset a gas alarm, press the POWER/MODE button after the gas
reading falls below the low alarm point. If a TWA or STEL alarm has been
activated, it cannot be reset unless you turn off the unit.
NOTE: Even though the gas concentration may have returned to normal
or may have fallen below the low alarm point, the alarm
indications will continue until you have reset the alarm using the
POWER/MODE button.
Over Range
Concentration of gas
rises above the
measuring limit of the
01 Series. (Or there
could be a problem
with the unit.)
• Gas reading
replacedbyblinking
brackets.
• Back light turns on.
• Pulsingtoneoccurs
once per second.
• Unit vibrates once
per second.
• Alarm light flashes.
Low Battery Warning • Last remaining bar
on the right in
battery icon
flashes.
•None
Dead Battery Alarm • Gas reading
replaced by FAIL.
• Battery icon
flashes.
• Doublepulsingtone
(two pulses in quick
succession) occurs
once a second.
Sensor Failure • Gas reading
replaced by FAIL.• Doublepulsingtone (two pulses in quick
succession) once a
second.
System Failure • Gas reading
replaced by FAIL.
•SYSdisplaysbelow
FAIL.
• Doublepulsingtone
(two pulses in quick
succession) once a
second.
Table 3: Alarm Types and Indications
Alarm Type LCD Indications Other Indications

15 • Operation 01 Series Operator’s Manual
Responding to Alarms
This section describes response to gas, over range, battery, sensor failure,
and system failure alarms.
Responding to Gas Alarms
1. Follow your established procedure for an increasing gas condition or a
decreasing oxygen condition.
2. Reset the alarm by pressing and releasing the POWER/MODE button
after the alarm condition has been cleared.
Responding to an Over Range Alarm
WARNING: An over range condition may indicate an extreme toxic
gas or oxygen concentration. Confirm the gas
concentration with a different 01 Series or with another
gas detecting device.
1. Follow your established procedure for an increasing gas condition.
2. Reset the alarm by pressing and releasing the POWER/MODE button
after the alarm condition has cleared.
3. Calibrate the 01 Series as described in the calibration section of this
manual.
4. If the over range condition continues, you may need to replace the
sensor.
5. If the over range condition continues after you have replaced the
sensor, contact RKI Instruments, Inc. for further instructions.
Responding to Battery Alarms
WARNING: The 01 Series is not operational as a gas monitoring
device during a dead battery alarm. Take the 01 Series to
a non-hazardous area and change the alkaline batteries
as described in “Replacing the Batteries”.
The 01 Series is fully functional in a low battery warning condition.
However, only a couple of days of operation may remain depending on
certain conditions such as alarm occurrences and how often the backlight
comes on.
NOTE: Alarms and the back light feature consume battery power and
reduce the amount of operating time remaining.
When a low battery warning occurs, change the batteries as soon as