Riken Keiki GX-2001 User manual

Model GX-2001
Operator’s Manual
2-7-6 Azusawa Itabashi-ku Tokyo,

Warranty
RIKEN KEIKI CO., LTD.., warrants gas alarm equipment sold by us to be free
from defects in materials and workmanship, and performance for a period of
one year from date of shipment from RIKEN KEIKI CO., LTD.. Any parts found
defective within that 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:
Absorbent cartridges Batteries
Pump diaphragms and valves Filter elements
Fuses
Warranty is voided by abuse including mechanical damage, alteration, rough
handling, or repairs 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 RIKEN KEIKI CO., LTD..,
INCLUDING BUT NOT LIMITED TO THE WARRANTY OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL RIKEN KEIKI
CO., LTD.., 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 RIKEN KEIKI CO.,
LTD..
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.

Table of Contents
Introduction ...................................................................................1
Specifications..................................................................................2
Description .....................................................................................3
Case .......................................................................................................... 3
Sensors ...................................................................................................... 3
LCD............................................................................................................ 4
Control Buttons............................................................................................ 4
Printed Circuit Boards .................................................................................... 5
Alarm Lights.................................................................................................5
Buzzer/Vibrator ........................................................................................... .5
Ni-cad Battery Pack...................................................................................... 5
Belt Clip...................................................................................................... 5
Battery Charger............................................................................................ 5
Start Up ........................................................................................ 6
Start-up Procedure...................................................................................... 6
Performing a Demand Zero............................................................................. 6
Turning Off the Model GX-2001 ...................................................................... 6
Operation...................................................................................... 7
Normal Operation.......................................................................................... 7
Displaying Peak Readings............................................................................... 7
Displaying STEL and TWA Readings .................................................................8
Alarms ....................................................................................................... 8
Displaying and Setting the Alarm Points...........................................11
Setting the Time and Date .............................................................13

Calibration....................................................................................14
Setting the Zero Readings for All Target Gasses ................................................14
Single Calibration.........................................................................................14
Auto Calibration...........................................................................................16
Maintenance.................................................................................18
Troubleshooting...........................................................................................18
Recharging the Ni-cad Battery Pack ...............................................................19
Replacing the Ni-cad Battery Pack..................................................................19
Replacing the Sensor Cover ...........................................................................20
Replacing a Sensor................................................................................................................................................20

Introduction
Using an advanced detection system consisting of four gas sensors, the Model
GX-2001 Personal Four-Gas Monitor detects the presence of combustible gas,
oxygen (O2), carbon monoxide (CO), and hydrogen sulfide (H2S)
simultaneously. The Model GX-2001’s compact size and easy-to-use design
makes it ideally suited for a wide range of applications, including sewage
treatment plants, utility manholes, tunnels, hazardous waste sites, power
stations, petrochemical refineries, mines, paper mills, drilling rigs, and fire
fighting stations. The Model GX-2001 offers a full range of features, including:
lSimultaneous four-gas monitoring of combustible gases, O2, CO, and H2S
lLiquid crystal display (LCD) for complete and understandable information at
a glance
lDistinctive audible alarms for dangerous gas conditions and for unit
malfunction
lMicroprocessor control for reliability, ease of use, and advanced
capabilities
lAlarm trend data
lData logging functions
lSTEL/TWA and ceiling alarm display
lPeak hold and average readouts
lBuilt-in time function
lRF shielded and high impact plastic case of very compact size and light
weight
lBelt clip for “hands-free” gas monitoring
lCSA classified for Class I, Division I, Groups A, B, C, and D hazardous
atmospheres
WARNING: The Model GX-2001 detects oxygen deficiency and elevated
levels of oxygen, combustible gases, carbon monoxide, and
hydrogen sulfide, all of which can be dangerous or life
threatening. When using the Model GX-2001, 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.

Specifications
Table 1 : Model GX-2001 Specifications
Model Name Model GX-2001
Target Gas Combustibles
(HC, CH4, etc.) Oxygen (O2) Hydrogen Sulfide (H2S) Carbon Monoxide (CO)
Range
(Increment) 0-100% LEL (1% LEL) 0-40.0 vol% (0.1 vol%) 0-150 ppm (0.5 ppm) 0-300 ppm (1 ppm)
Detection Method Diffusion
Response Time T90 Within 30 Seconds
Display 7-Segment Digital LCD
Gas Alarms
(Factory Settings) Alarm 1: 10% LEL Alarm 2: 50% LEL
Over: 100% LEL
Alarm 1: 19.5 vol%
(Decreasing)
Alarm 2: 23.5 vol%
Over: 40.0 vol%
Alarm 1: 10 ppm
Alarm 2: 30 ppm
TWA: 10 ppm
STEL: 15 ppm
Alarm 1: 25 ppm
Alarm 2: 50 ppm
TWA: 25 ppm
STEL: 200 ppm
Operating
Temperature and
Humidity
-10 to 40o C/Below 85% RH (Without Condensation)
Power Supply Ni-cad Battery Pack (2.4 VDC Nominal), Direct Charging
Continuous
Operating Hours Up to 12 Hours (No Alarms after Full Charge)
Case High-impact Plastic, RF Shielded, Dust and Weather Proof
Standard
Accessories Ni-Cad Battery Pack, Belt Clip
Optional
Accessories
• Charging Station, 115 VAC Powered
• Charging Station with PC Communication Function for Datalog
Downloading
• Communication Computer Cable
• Communication Software (Windows® 95, 98, & NT)
• Automatic Calibraiton Station
• Hand Aspirated Sample Draw with Hose and Probe
• Wrist Strap
Dimensions and
Weight Dimensions: 2.8 (H), 2.2 (W), 1.1 (D) inches Weight: Approximately 6 oz.

Description
This section describes the components of the Model GX-2001. These
components include the Model GX-2001’s case, sensors, LCD, control buttons,
printed circuit boards, alarm lights, buzzer/vibrator, Ni-cad battery pack, belt
clip, and battery charger.
Case
The Model GX-2001’s sturdy, high-impact plastic and metal case is radio
frequency (RF) resistant, and is suitable for use in many environmental
conditions, indoors and out. The unit is dust proof and weather resistant..
On the front of the case is a digital LCD, which shows gas concentrations,
battery level, time, and other readings including TWA, STEL, and peak gas
levels. Below the LCD are three control buttons. The first button on the left is
labeled MODE/POWER. The other buttons are labeled DISP and AIR,
respectively.
Beneath the control buttons is the buzzer, which is located inside the unit.
On the right side of the Model GX-2001 are the diffusion ports for the gas
sensors located inside the case. These sensors are, from top to bottom (and
are marked on the case), HC (combustible gases), O2, CO, and H2S.
On the left side of the case are two brass recharging contacts, which are used
when the unit is placed in the battery charger, and on top of the case are two
alarm lights. On the back of the unit is a rugged metal belt clip enabling hands-
free gas monitoring.
Sensors
The Model GX-2001 uses four sensors to monitor HC (combustible gases), O2,
CO, and H2S simultaneously. The sensors are protected by filters that allow
atmosphere to diffuse inward. The sensors use different detection principles,
as described below.
Combustible Gas Sensor
The LEL sensor detects combustible gas and vapors in the atmosphere with a
catalytic platinum element. The reaction of gas with oxygen on the catalyst
causes a change in the resistance of the element. The current is amplified by
the Model GX-2001’s circuitry, converted to a measurement of combustible gas
concentration, and displayed on the LCD.
Oxygen Sensor
The O2sensor is an electrochemical cell. 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 Model GX-
2001’s circuitry, converted to a measurement of gas concentration, and
displayed on the LCD.
CO and H2S Sensors

The CO and H2S sensors are electrochemical cells that consist of two precious
metal electrodes in an acid electrolyte. A gas permeable membrane covers the
cell and allows gas to diffuse into the electrolyte. The gas reacts in the cell
and produces a current proportional to the concentration of the target gas.
The current is amplified by the Model GX-2001’s circuitry, converted to a
measurement of gas concentration, and displayed on the LCD.
LCD
The LCD is visible through the GX-2001’s front panel. Target gas
concentrations, the time, battery condition, and alarm indications are
displayed on the LCD.
Control Buttons
Below the LCD are the control buttons. These buttons are MODE/POWER,
DISP, and AIR. They turn on the power to the Model GX-2001, and turn it off.
They control what is displayed on the LCD, including battery level, time, date,
and year, gas concentrations, peak, TWA, and STEL readings, as well as other
messages. They also allow you to perform a Demand Zero, change alarm
points, change the date and time, and calibrate the instrument. The functions
performed by the control buttons are summarized in the following table:
Table 2 : The Control Buttons of the Model GX-2001
Button Function
MODE/POWER • Turns the unit on and off.
• Turns the LCD back light on and off.
•
Displays peak readings (low minimum and high maximum readings
for O2).
• Resets the alarm circuit (gas alarms).
• Enters Calibration Mode with the AIR button.
• Enters Alarm Adjustment Mode with the AIR button.
• Enters Time Adjustment Mode with the DISP button.
DISP • Displays the next target gas when the unit is in Measuring Mode.
• Enters Time Adjustment Mode with the MODE/POWER button.
• Decreases settings when the unit is in Alarm Adjustment Mode or
Time Adjustment Mode.
• Toggles between field calibration and auto calibration when the
unit is in Calibration Mode.
AIR • Adjusts LCD readings when the a Demand Zero is performed.
• Enters Calibration Mode with the MODE/POWER button.
• Enters Alarm Adjustment Mode with the MODE/POWER button.
• Increases settings when the unit is in Alarm Adjustment Mode or
Time Adjustment Mode.
• Toggles between field calibration and auto calibration when the
unit is in Calibration Mode.

Printed Circuit Boards
The primary function of the Model GX-2001’s three printed circuit boards are to
amplify the current sent to them from the four gas sensors, convert the
current to a meaningful measurement of gas concentration, display the gas
concentration on the LCD, store peak, STEL, and TWA 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 the Model GX-2001’s
time function and the various operating modes of the unit. Note that the
printed circuit boards contain no serviceable parts.
Alarm Lights
The Model GX-2001 has two alarm lights mounted on top of the unit. The alarm
lights are two red LEDs that alert you to gas, low battery, and sensor failure
alarms.
Buzzer/Vibrator
A solid-state electronic buzzer/vibrator is mounted inside the front case of the
Model GX-2001. The buzzer/vibrator sounds and vibrates for gas alarms, and
it sounds for unit malfunctions, low battery voltage, and as an indicator during
normal use of the many display options of the Model GX-2001.
Ni-cad Battery Pack
Inside the Model GX-2001 is a Ni-cad battery pack that supplies 2.4 V to the
unit. The battery will run the unit for approximately 12 hours when no alarms
have been activated during that time period. The battery is fully rechargeable
when the Model GX-2001 is placed into the battery charger. The battery icon
on the LCD shows the charge remaining in the battery. When the Model GX-
2001 detects a low battery voltage, a low battery warning is activated. The
battery can be replaced by removing the belt clip on the back of the Model
GX-2001. See the maintenance section of this manual for instructions about
recharging and replacing the battery.
Belt Clip
On the back of the Model GX-2001 is a belt clip. The belt clip permits the unit
to be worn on a belt or to be clipped to a pocket for hands-free gas
monitoring.
Battery Charger
The Model GX-2001 has two optional battery chargers. Both are used to
recharge the unit’s Ni-cad battery pack and both serve as a convenient
station for auto calibration. The battery charger with the PC communication
feature has a datalogging port for the down loading of data from the Model
GX-2001 to the PC. See “Parts List” for more information.

Start Up
This section explains how to start up the Model GX-2001 and to get it ready
for operation.
Start-up Procedure
1. Press and hold the MODE/POWER button for one second to turn on the
Model GX-2001 and to activate its LCD. The alarm lights flash and the
buzzer sounds.
2. The Model GX-2001 tests all elements of the LCD, then displays the year,
month, day, and time before displaying the battery voltage. The buzzer
sounds again after the battery voltage is displayed.
CAUTION: If the battery level is low or if the battery icon is flashing and the
unit’s buzzer sounds, recharge the Model GX-2001’s Ni-cad
battery.
3. The four gas sensors inside the Model GX-2001 begin working, and the
concentrations of the target gases are displayed on the LCD in sequential
order beginning with oxygen. The Model GX-2001 is now in Measuring
Mode.
In Measuring Mode, battery level, time, and gas concentrations are
displayed on the LCD. The Model GX-2001 cycles through the four target
gases, starting with O2, then H2S, CO, and HC. Oxygen is displayed as a
percentage (%), H2S and CO as parts per million (ppm), and HC
(combustible gases) as a percentage of the lower explosive limit (% LEL).
NOTE: You can test the oxygen sensor and alarm circuit by exhaling into the
oxygen sensor. When the LCD reading falls below the alarm point for
oxygen, the buzzer will sound, the vibrator will activate, the LCD
reading for oxygen will flash, and the alarm lights will turn on.
Performing a Demand Zero
Before using the Model GX-2001, it is a good idea to set the zero reading
(demand zero) for the target gasses to ensure accurate gas readings in the
monitoring environment.
1. Find a fresh-air environment.
2. With the unit on and in Measuring Mode, press and hold the AIR button for
about three seconds to allow the Model GX-2001 to set the zero reading
for HC, CO, and H2S and to set the span for O2.
3. While you are pressing the AIR button, the LCD displays “Hold,” a prompt
for you to keep pressing the AIR button.
4. When the zero readings have been set, the LCD displays “Adj,” which
prompts you to release the AIR button.
Turning Off the Model GX-2001
1. Press and hold the MODE/POWER button for about five seconds to turn off
the unit.
2. The buzzer will sound and the LCD back light will flash.
3. Release the button when the LCD is blank. The unit is off.