RKI Instruments GX-94 User manual

RKI Instruments, Inc.
1855 Whipple Road
Hayward, CA 94544
800-754-5165
GX-94
Operator’s Manual
Part Number: 71-0008RK
Edition: Revision P2
Released: 6/10/2002

Page 1 • Warranty GX-94 Operator’s Manual
WARRANTY
RKI Instruments, Inc., warrants the GX-94 sold by us to be free from defects in
materials, workmanship, and performance for a period of one year from the date
of shipment from RKI Instruments, Inc. Any parts found defective that 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:
Warranty is voided by abuse including mechanical damage, alteration, rough han-
dling, 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 contin-
gent expenses incurred without our prior approval.
This warranty is expressly in lieu of any and all other warranties and representa-
tions, 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 fit-
ness for a particular purpose. In no 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 dis-
tributors, 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
Batteries

Page 2 • Table of Contents GX-94 Operator’s Manual
TABLE OF CONTENTS
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Case. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Battery Compartment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Interface Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Buzzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Belt Clip and Strap Flanges . . . . . . . . . . . . . . . . . . . . . . . . 10
Diffusion Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Circuit Boards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Starting Up the GX-94 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Turning Off the GX-94 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
ALARMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Alarm Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Resetting Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
DISPLAY MODE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
User and Station ID Screen . . . . . . . . . . . . . . . . . . . . . . . . 21
Peak Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Average Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Elapsed Time Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
STEL Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
TWA Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Battery Voltage Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Time/Date/Temperature Screen. . . . . . . . . . . . . . . . . . . . . 25
Clear Data Logger Screens . . . . . . . . . . . . . . . . . . . . . . . . 26
Remaining Log Time Screen . . . . . . . . . . . . . . . . . . . . . . . 26

GX-94 Operator’s Manual Table of Contents • Page 3
SETUP MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Tips for Using Setup Mode. . . . . . . . . . . . . . . . . . . . . . . . . 27
Entering Setup Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Resetting the NVRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Updating the Gas Combination . . . . . . . . . . . . . . . . . . . . . 29
Viewing and Setting Alarms . . . . . . . . . . . . . . . . . . . . . . . . 29
Setting the Serial Number . . . . . . . . . . . . . . . . . . . . . . . . . 30
Setting the Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Setting the Logging Frequency . . . . . . . . . . . . . . . . . . . . . 31
Setting the Alarm Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Setting the Lunch Break Function . . . . . . . . . . . . . . . . . . . 31
Setting the ID Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Setting the Calibration Reminder . . . . . . . . . . . . . . . . . . . . 31
Setting the Data Logging Alarm . . . . . . . . . . . . . . . . . . . . . 32
Setting the Buzzer Frequency . . . . . . . . . . . . . . . . . . . . . . 32
Displaying Circuit Voltages. . . . . . . . . . . . . . . . . . . . . . . . . 32
Returning to Normal Operation . . . . . . . . . . . . . . . . . . . . . 32
CALIBRATION MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Calibration Supplies and Equipment . . . . . . . . . . . . . . . . . 33
Preparation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Calibrating the GX-94. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Setting the Date and Time . . . . . . . . . . . . . . . . . . . . . . . . . 39
MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Main Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Lithium Memory Backup Battery . . . . . . . . . . . . . . . . . . . . 42
Charcoal Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Sensor Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
ACCESSORIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Sample-Drawing Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
PARTS LIST. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

GX-94 Operator’s Manual Page 4
INTRODUCTION
The RKI Model GX-94 is an advanced gas detection instrument in use
internationally for personal protection in a variety of industries.The GX-
94 is rugged, compact, convenient, and offers a full range of features,
including:
• Simultaneous detection of two, three, or four gases.The standard
configuration is combustible gas in the %LEL range (HC,) oxygen
deficiency (O
2
), carbon monoxide (CO), and hydrogen sulfide (H
2
S).
• Dot-matrix liquid crystal display (LCD) for complete, understandable
information at a glance.
• Visual and audible alarms for alarm conditions and malfunctions.
• Underwriters Laboratories Classification for intrinsic safety for Class
I, Division I, Groups A, B, C, and D hazardous atmospheres.
• Microprocessor control for all functions, including data logging and
user adjustable alarms.
• Compact size.
• Belt clip and shoulder strap standard.
WARNING
T HE GX-94 IS DESIGNED TO DETECT COMBUSTIBLE GAS ,
OXYGEN DEFICIENCY , HYDROGEN SULFIDE , AND CARBON
MONOXIDE
, WHICH CAN BE LETHAL . U SERS MUST FOLLOW THE
INSTRUCTIONS
AND WARNINGS IN THIS MANUAL TO ASSURE
PROPER
AND SAFE OPERATION OF THE INSTRUMENT .

Page 5 GX-94 Operator’s Manual
SPECIFICATIONS
Table1 lists physical and environmental specifications for the GX-94.
Table 2 lists specifications for the GX-94’s sensors and channels.
Table 1: GX-94 Specifications
Target Gases Combustible Gas (HC); Oxygen (O
2
), Carbon Monox-
ide (CO), Hydrogen Sulfide (H
2
S)
Case RFI Shielded High Impact ABS Plastic
Safety/Regulatory UL Classified Instrinsically Safe for Class I, Division I,
Groups A, B, C, & D
Dimensions 3.54” x 2.52” x 6.3” (90 x 64 x 160 mm)
Weight 25 ounces (700 g)
Power Two C size alkaline batteries (optional Ni-Cd batteries
externally charged)
Continuous Operat-
ing Hours (non-alarm
operation)
Alkaline: 12 hours
Ni-Cd: 8 hours
Operating Tempera-
ture & Humidity 14°F to 104°F (-10°C to 40°C) 0 to 95% RH, non-condensing

GX-94 Operator’s Manual Page 6
1 Alarms are user adjustable.See Viewing and Setting Alarms in the setup mode section.
Table 2: Sensor/Channel Specifications
Combustible Gas
(HC) Oxygen Hydrogen
Sulfide Carbon Monoxide
Detection
Range 0 - 100% LEL 0 - 40.0% 0 - 100.0 ppm 0 - 500 ppm
Display
Increments 1% LEL 0.1% 0.5 ppm 1 ppm
Low Alarm
1
10% LEL 19.5%
(decreasing) 10.0 ppm 25 ppm
High Alarm
1
50% LEL 23.5%
(increasing) ---- ----
TWA Alarm
1
---- ---- 10.0 ppm 25 ppm
STEL
Alarm
1
---- ---- 15.0 ppm 400 ppm
Detection
Principle Catalytic Combustion Electrochem- ical (gal-
vanic type)
Cell
Electrochemi-
cal Cell Electrochem- ical Cell
Ceiling
Alarm --- ---- Off Off
Accuracy
0 - 20% LEL
± 2% LEL
21% - 100% LEL
± 5% LEL
± 0.5% Oxy-
gen 0 - 30 ppm
±1.5 ppm
31 - 100 ppm
±5 ppm
0 - 50 ppm
±5 ppm
51 - 150 ppm
± 15 ppm
151 - 500
ppm
± 25 ppm

Page 7 GX-94 Operator’s Manual
DESCRIPTION
Case
The GX-94 has a high impact, RF shielded ABS plastic case with a rub-
ber guard that also functions as a water-resistant seal between the two
halves of the case.The case has sturdy plastic flanges on the left and
right sides for installation of the shoulder strap.It has an opening on the
top front of the GX-94 for the buzzer sound and it has sensor ports
which allow diffusion through the sensor screen on the top rear of the
GX-94.
Control Panel
Figure 1: GX-94 Control Panel
The control panel is at the front of the GX-94 for easy access when the
Control Button, 4X
INPUT
(Shift)
(ADJ.)
AIR Display
ON/OFF
Alarm
Display
Model GX-94
Light Sensor
AlarmLED

GX-94 Operator’s Manual Page 8
GX-94 is carried or clipped on a belt. It contains the display, the touch-
pad buttons that control the many functions of the GX-94, the Alarm
LED, and the light sensor.The display is to the left of the buttons and
simultaneously shows the gas readings for all active channels.The
touch-pad buttons are low profile to reduce the risk of accidental activa-
tion and damage.The functions of the control panel buttons are
described below in Table 3.
Alarm LED
A red light-emitting diode (LED) is visible through a lens located on the
upper right front of the control panel above the buttons.It provides a
visual indication for alarms and malfunctions.
Light Sensor
A light sensor is located to the left of the alarm LED.It monitors the level
of ambient light.When the ambient light level becomes too low to allow
Table 3: GX-94 Button Functions
Button Function(s)
ON/OFF/INPUT • turns the GX-94 on and off
• used during setup and calibration to enter values
DISPLAY/(ADJ.) • activates display modes
• enters instructions into the GX-94’s microprocessor
AIR/▲• activates the demand zero function (automatically
adjusts the GX-94 in fresh air conditions)
• scrolls through the various instrument modes
• adjusts parameters in the various instrument modes
• enters instructions into the GX-94’s microprocessor
SHIFT/▼• scrolls through the various instrument modes
• adjusts parameters in the various instrument modes
• enters instructions into the GX-94’s microprocessor
• resets alarms if GX-94 is programmed for latching
alarms

Page 9 GX-94 Operator’s Manual
easy viewing of the display, the light sensor prompts the display back-
light to turn on.
Note
The backlight does not operate in Setup Mode.
Figure 2:Top & Side views of the GX-94
Battery Compartment
The battery compartment is located on the top of the GX-94.A tethered
battery cover allows easy battery replacement.It is tethered to the inter-
face port cover.
Top Case
Bottom Case
Belt Clip
Battery Cover
Screw
Battery Cover
Buzzer
Opening
Shoulder Strap
Flange, 2X
Interface
Port Cover
Sensor Screen
Threaded Hole for
Sample Adapter