Portable Gas Monitor - Riken Keiki

Portable Gas Monitor RIKEN KEIKI GX-2009 Portable Gas Monitor Operator’ s Manual Part Number: 71-0158RK Revision: H Released: 6/ 18/ 14 GX-2009 Operator’ s Manual WARNING Read and understand this instruction manual before operating instru ment. 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 correct 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 fre quencies for most applications are betwee n 1 and 3 months, but can be required more often or less often based on your usage. GX-2009 Operator’ s Manual Warranty Warranty RKI Instruments, Inc. warrants the GX-2009 sold by us to be free from defects in materials, workmanship, and performance for a period of two years from the date of shipment from RKI Instruments, Inc. This includes the instrument and the original sensors. Replacement parts are warranted for 1 year from the date of their ship ment 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: 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 replac ement costs, local repair costs, transportation costs, or contingent expenses incurred without our prior approval. T HIS WARRANTY IS EXPRESSLY IN LIEU OF ANY AND ALL OTHER WAR RANTIES AND REPRESENTATIONS , EXPRESSED OR IMPLIED , AND ALL OTHER OBLIGATIO NS OR LIABILITIES ON THE PART OF RKI I NSTRUMENTS , I NC . INCLUDING BUT NOT LIMITED TO THE WARRANTY OF MERCHANTABILITY OR FITNE SS FOR A PARTICULAR PURPOSE . I N NO EVENT SHALL RKI I NSTRUMENTS , I NC . BE LIABLE FOR INDIRECT , INCIDENTAL , OR CONSEQUENTIAL LOSS OR DAMAGE OF ANY KIND CONNECTED WITH THE USE OF ITS PRODUCTS OR FAILURE OF ITS PRODUC TS 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 GX-2009 Operator’ s Manual Table of Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Alligator & Belt Clips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Sensor Retainer/ Sensor Retainer Gasket/ Sensor Cover Retainer . . . . . . . . . . . . 6 Scrubber Filters/ Sensor Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 LCD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Control Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Printed Circuit Boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Alarm LED Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Buzzer & Vibrator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 NiMH Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Charging Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 Start-up Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Performing a Fresh Air Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Turning Off the GX-2009 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Display Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Combustible Gas Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Aspirator Adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Data Logging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 GX-2009 Setup Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Calibration Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Using Calibration Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Setting the Date & Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Performing a Fresh Air Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Performing a Span Adjustment in AUTO CAL. . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Performing a Span Adjustment in ONE CAL. . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Performing a Bump Test in BUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Discharging the Batteries With the REFRESH Function. . . . . . . . . . . . . . . . . . . 45 GX-2009 Operator’ s Manual Table of Contents User Setup Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Using User Setup Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Setting the Date & Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Performing a Fresh Air Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Performing a Span Adjustment in AUTO CAL. . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Performing a Span Adjustment in ONE CAL. . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Setting the Alarm Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Setting the Password . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Recharging the GX-2009’ s NiMH Batteries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Replacing the GX-2009’ s NiMH Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Checking the Combustible Gas Sensor’ s Condition . . . . . . . . . . . . . . . . . . . . . . 61 Replacing the Scrubber Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Replacing the Sensor Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Replacing a Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66 WARNING: Understand manual before operating. Substitution of components may impair intrinsic safety. To prevent ignition of a hazar dous atmosphere, ba tteries must only be changed or charged in an area known to be nonhazardous. Not tested in oxygen enriched atmospheres ( above 21% ) . NOTE: RKI Instruments, Inc. recommends that you refer to ISA-RP12.13, Part II-1987 or an equivalent international recommended practice for guidance in the use of combustible gas detection instruments. 1 • Introduction GX-2009 Operator’ s Manual Introduction Using an advanced detection system consisting of four gas sensors, the GX-2009 personal four-gas monitor detects the presence of combustible gas, oxygen ( O 2 ) , carbon monoxide ( CO) , and hydrogen sulfide ( H 2 S) simultaneously. The GX-2009’ s com pact size and easy-to-use design makes it ideally suited for a wide rang e 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 GX-2009 offers a full range of features, including: • Simultaneous four-gas monitoring and display of combustible gases, O 2 , CO, and H 2 S • Backlit LCD ( liquid crystal display) for complete and understandable information at a glance • Distinctive audible/ vibrating alarms for dangerous gas conditions and audible alarms for unit malfunction • Microprocessor control for reliability, ease of use, and advanced capabilities • Resistance to RF ( radio frequency) interference • Datalogging including interval trend data and alarm trend data • STEL/ TWA and over range alarm display • Peak hold readouts • Built-in time function • Lightweight and compact high impact plastic case • Rotatable alligator clip for “ hands-free” gas monitoring, belt clip optional • CSA classified for Class I, Division I, Groups A, B, C, and D hazardous atmospheres WARNING: The GX-2009 detects oxyg en 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 GX-2009, you must follow the instructions and warnings in this manual to assure proper and safe oper ation of the unit and to minimize the risk of personal injury. Be sure to maintain and periodically calibrate th e GX-2009 as described in this manual. NOTE: Only the combustible gas detector portion of this instrument has been assessed for performance. GX-2009 Operator’ s Ma nual Specifications • 2 Specifications Table 1: Model GX-2009 Specifications Target Gas Combustibles, Methane ( CH4) calibration standard* Oxygen ( O 2 ) Hydrogen Sulfide ( H 2 S) Carbon Monoxide ( CO) Range ( Increment) 0-100% LEL ( 1% LEL) 0-40.0 vol% ( 0.1 vol% ) 0-100.0 ppm ( 0.5 ppm) 0-500 ppm ( 1 ppm) Detection Method Diffusion Response Time T90 Within 30 Seconds Accuracy ± 5% of reading or ± 2% LEL ( whichever is greater) ± 0.5% O 2 ± 5% of reading or ± 2 ppm H 2 S ( whichever is greater) ± 5% of reading or ± 5 ppm CO ( whichever is greater) Display 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: 5.0 ppm Alarm 2: 30.0 ppm Over: 100.0 ppm TWA: 1.0 ppm STEL: 5.0 ppm Alarm 1: 25 ppm Alarm 2: 50 ppm Over: 300 ppm TWA: 25 ppm STEL: 200 ppm Operating Temperature and Humidity -20 to 50 o C/ Below 85% RH ( Without Condensation) Safety/ Regulatory C US 186718 CSA classified, “ C/ US” , as Intrinsi cally Safe. Exia. Class I, Groups A, B, C, & D. Class I, Zone 0, Group IIC. Temperature Code T3C. Power Supply NiMH Batteries ( 2.4 VDC Nominal) , Direct Charging 3 • Specifications GX-2009 Operator’ s Manual NOTE: The bump test function in Calibration Mode is included in instruments with firmware version 03955 or later installed. See page 40 for a description of the bump test function. GX-2009 instruments shipped after May 2011 include the bump test function. Instruments that have a serial number starting with 04516 or later shipped from the factory with the bump test function available. Instruments that have a serial number starting with 04515 did not include the bump test function when shipped from the factory. The factory setting for the bump test function is off. Continuous Operating Hours Up to 20 Hours ( Non Alarm Operation After Full Charge) Charge Time 3 hours for a full charge Case High-impact Plastic, Dust and Water Resistant to IP-67 Required Accessories AC or DC Charging Station, AC Charging Station Available For From 1 to 5 Instruments Other Accessories • IrDA/ USB cable for downloading data to computer • GX-2009 Data Logger Management Program ( Windows ® 2000, XP, Vista) • GX-2009 Setup Program ( Windows ® 2000, XP, Vista) • Automatic Calibration Station • Hand Aspirated Sample Draw Adapter with Hose and Probe • Wrist Strap ( included with every unit) Dimensions and Weight Dimensions: 2.7 H, 3.0 W, 1.0 D inches Approx. 70 H, 75 W, 25 D mm Weight: 4.6 oz. * The GX-2009 is also available set up for general hydrocarbons and calibrated to a combustible gas other than methane, such as isobutane. Consult RKI Instruments, Inc. for further information. Table 1: Model GX-2009 Specifications GX-2009 Operator’ s Manual Description • 4 Description This section describes the GX-2009’ s components and the charging station. These components include the GX-2009’ s case, alligator and belt clips, sensor retainer, sensor reta iner gasket, sensor cover retainer, scrubber filters, sensor cover, sensors, LCD, control buttons, printed circuit boards, alarm LED arrays, buzzer, vibrator, batteries, and charging station. POW ER MODE AIR LED Arrays Front Buzzer Sound Opening IR Port Top Buzzer Sound Opening H 2 SCO% LELO 2 RKI GX-2009 Sensor Diffusion Port, 4X Control Buttons Wrist Strap Sensor Retainer LCD Sensor Cover, Over All Sensors Sensor Cover Retainer Figure 1: GX-2009, Front & Bottom View 5 • Description GX-2009 Operator’ s Manual Case The GX-2009’ s sturdy, high-impact plastic case is suitable for use in many environmental conditions, indoors and out. The unit is dust proof and water resistant. Rubber overmolded surfaces on much of the case help protect it from impact damage and aid in holding the instrument in your hand. A clear plastic window through which the LCD can be viewed is located on the front of the case. Three brass charging contacts that are used when the GX-2009 is placed in the charging station are on the back of the case. Four sensor diffusion ports are located on the bottom of the case. The ports are labelled as follows from left to right: H 2 S, CO, HC, and O2. Three frosted windows, one on the left side, one of the right side, and one on top, cover alarm LED arrays. There are two buzzer sound openings, one on the front below the LCD and one on the top behind the top LED array. An IR ( infrared) communication port is locate d on the top left side which is used to transfer information when the instrument is used with one of the calibration or downloading accessories. There are three threaded inserts on the back of the case. These are used to mount the alligator clip or the optional belt clip. Threaded Inserts Battery Charging Contacts Figure 2: GX-2009 Rear View GX-2009 Operator’ s Manual Description • 6 Alligator & Belt Clips The GX-2009 is available with two types of clips, the standard alligator clip and the optional belt clip. Both are illustrated in Figure 3. The alligator clip can be used to attach the GX-2009 to clothing or a belt. Teeth in the alligator clip’ s jaws prevent the unit from slipping off. The alligator clip can be rotated to change how the instrument is oriented when worn. The belt clip is used to easily clip the GX-2009 on a belt. Sensor Retainer/ Sensor Retainer Gasket/ Sensor Cover Retainer The sensor retainer holds the gas sensors in place and snaps onto the bottom of the case. It has 4 diffusion ports, one for each sensor, and has recessed areas in it for the charcoal filter, and the H 2 S removal filters. It also has indexing features for the sensor retainer gasket. The sensor retainer gasket seats onto the sensor retainer and seals the interface between the sensor retainer, sensor cover, and sensor cover retainer. The sensor cover retainer snaps onto th e sensor retainer. Two screws secure the sensor retainer and the sensor cover retainer to the case. Scrubber Filters/ Sensor Cover Charcoal Filter Disk The charcoal filter disk is located in the CO sensor diffusion port of the sensor retainer. It is black, has a woven texture, and is impregnated with an H 2 S absorbing material. It fits into a recessed area of that port. The CO Alligator Clip Belt Clip Figure 3: Alligator and Belt Clips 7 • Description GX-2009 Operator’ s Manual sensor will respond if exposed to H 2 S and certain hydrocarbon gasses. The charcoal filter scrubs these gasses out of the gas sampled to avoid false CO readings. The H 2 S absorbing material added to the charcoal filter extends it’ s H 2 S absorbing life. If false CO readings are noticed, especially high readings in the presence of H 2 S, change the charcoal filter disk. H 2 S Removal Filter Disks One H 2 S removal filter disk is located in a recessed area of the combustible gas sensor diffusion port in the sensor retainer. The H 2 S removal filter disk is white when new. It scrubs H 2 S out of the gas sampled to increase the life of the combustible sensor. It darkens as it absorbs H 2 S and must be changed when it turns to a dark brown color. The recommended replacement frequency will depend on how often the unit is exposed to H 2 S and the concentration. Check the condition of the H 2 S removal filter disk quarterly. Sensor Cover The sensor cover is white and protects the scrubber filters and sensors from dust and water. It fits on the sensor retainer gasket over all the sensor diffusion ports and is secured in place by the sensor cover retainer. If the sensor cover becomes dirty, the response time and accuracy of the GX- 2009 will be affected. Replace the se nsor cover if it appears dirty. Sensors The GX-2009 uses four sensors to monitor combustible gases, O 2 , CO, and H 2 S simultaneously. The sensors are protected from the environment by the sensor cover which allows ambient air to diffuse to the sensors. The sensors use different detection principles, as described below. Combustible Gas ( LEL) Sensor The combustible gas sensor detects combustible gas and vapors in the LEL ( lower explosive limit) range with a catalytic element. A sintered metal flame arrestor covers the element and allows ambient air to diffuse into the sensor. The reaction of gas with oxygen on the catalyst causes a change in the resistance of the element which af fects the current flowing through it. The current is amplified by the GX-2009’ s circuitry, converted to a measurement of combustible gas concentration, and displayed on the LCD. CAUTION: Do not expose the combustible sensor to high concentrations of combustible gas such as that from a butane lighter. Exposure to high concentrations of combustible gas may adversely affect the performance of the sensor. GX-2009 Operator’ s Manual Description • 8 Oxygen ( O 2 ) Sensor The O 2 sensor is a galvanic type 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 GX-2009’ s circuitry, converted to a measurement of gas concentration, and displayed on the LCD. CO and H 2 S Sensors The CO and H 2 S 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 GX-2009’ s circuitry, converted to a measurement of gas concentration, and displayed on the LCD. LCD The LCD ( liquid crystal display) is visible through the GX-2009’ s front window. Target gas concentrations, the time, battery condition, and alarm indications are displayed on the LCD. When either of the control buttons are pressed, the LCD backlight comes on for 30 seconds. Control Buttons Two control buttons are located below the display on either side of the front buzzer opening. The AIR button is on the left and the POWER MODE button is on the right. The functions performed by the control buttons are summarized in the following table: Table 2: GX-2009 Control Buttons Button Function POWER MODE • Turns the unit on and off • Turns the LCD back light on • Scrolls through Display Mode • Resets the alarm circuit ( gas alarms) • Enters Calibration Mode with the AIR button • Enters User Setup Mode with the AIR button • Selects a displayed item • Saves adjusted parameters • Selects displayed parameters 9 • Description GX-2009 Operator’ s Manual Printed Circuit Boards The primary function of the GX-2009’ s printed circuit boards is to amplify the signal sent to them from the four gas sensors, convert the signal to a 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 GX-2009’ s time function and various operating modes. NOTE: The printed circuit boards contain no user serviceable parts. Alarm LED Arrays Three red alarm LED ( light emitting diode) arrays are visible through frosted plastic lenses in the case. One is on the top, one on the left side, one on the right side of the case. The alarm LED arrays alert you to gas, low battery, and failure alarms. Buzzer & Vibrator A solid-state electronic buzzer is mounted inside the GX-2009’ s case. The buzzer sounds for gas alarms, failure alarms, and as an indicator during normal use of the GX-2009’ s various operating modes. A vibrating motor inside the GX-2009 case vibrates for gas alarms and as an indicator during normal use of the GX-2009’ s various operating modes. NiMH Batteries Two NiMH ( nickel metal hydride) batteries, each with an integral holder, supply 2.4 volts to power the GX-2009. The batteries will run the unit for up to 20 hours when no alarms have been activated during that time period. The batteries are designed to be charged while in the GX-2009 with the GX-2009 Charging Station. The batteries should not be removed from the GX-2009 unless they need to be replaced because they will no longer hold a charge. The battery icon in the lower left corner of the LCD shows the AIR • Turns the LCD back light on. • Performs a fresh air adjustment • Enters Calibration Mode with the MODE POWER button. • Enters User Setup Mode with the MODE POWER button. • Adjusts or changes displayed parameters Table 2: GX-2009 Control Buttons Button Function GX-2009 Operator’ s Manual Description • 10 charge remaining in the batteries. See “ Recharging the GX-2009’ s NiMH Batteries” on page 55 for instructions to recharge the batteries and “ Replacing the GX-2009’ s NiMH Batteries” on page 59 for instructions to replace the batteries. Charging Station The GX-2009’ s NiMH batteries are charged with the GX-2009 Charging Station. There are two types of chargi ng stations available, the standard AC powered charging station and the optional vehicle plug DC powered charging station. AC Powered Charging Station The standard AC powered charging station is available in configurations that charge from one to five instruments at a time. The single instrument charging station consists of one instrument charging base and an AC adapter. The AC adapter for the standard charging station plugs into a 115 VAC wall outlet and connects to the charging station with a jack on the end of a five foot DC output cable. The AC adapter will also work for 100 VAC or 220 VAC if an appropriate plug adapter is provided. The single instrument AC charging station is shown in Figure 4. Adapter Jack Charge LED Instrument Retaining Tabs Adapter Jack Charging Contacts Top View Rear View AC Adapter Charging Base Figure 4: GX-2009 Charging Stati on, Single Instrument Station Portable Gas Monitor , Portable Gas Monitor RIKEN KEIKI, Portable Gas Monitor RIKEN KEIKI GX-2009. Hub : MARKETING HP 0856 9139 8333, / 210-40911748. Email : mia_ brsinaga@ yahoo.com