RKI Instruments GX-94 Operator'S Manual Download Page 7

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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

10% LEL

19.5%
(decreasing)

10.0 ppm

25 ppm

High Alarm

50% LEL

23.5%
(increasing)

----

TWA Alarm

----

10.0 ppm

25 ppm

STEL
Alarm

----

15.0 ppm

400 ppm

Detection
Principle

Catalytic
Combustion

Electrochem-
ical (gal-
vanic type)
Cell

Electrochemi-
cal Cell

Electrochem-
ical Cell

Ceiling
Alarm

---

----

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

Summary of Contents for GX-94

Page 1: ...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 2: ...t 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 eve...

Page 3: ...rts 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 ...

Page 4: ...1 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 M...

Page 5: ...iquid 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...

Page 6: ... CO Hydrogen Sulfide H2S 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 Temp...

Page 7: ...m Display Increments 1 LEL 0 1 0 5 ppm 1 ppm Low Alarm1 10 LEL 19 5 decreasing 10 0 ppm 25 ppm High Alarm1 50 LEL 23 5 increasing TWA Alarm1 10 0 ppm 25 ppm STEL Alarm1 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 ...

Page 8: ...he 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...

Page 9: ...d 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 microprocess...

Page 10: ...op 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 ...

Page 11: ... PC connection cable and the GX 94 Downloading Software The interface port cover is tethered to the battery cover to reduce the risk of losing it Buzzer A solid state electronic buzzer is located inside the top of the case near the front behind a felt screen The buzzer sounds for gas alarms mal function low battery voltage and as an indicator during use of the con trol buttons Belt Clip and Strap ...

Page 12: ...s atmosphere to diffuse into the sensor The HC 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 which is converted by the GX 94 s circuitry into a reading of gas concentration Oxygen Sensor The oxygen O2 sensor is contained in a cylindrical shell with two co...

Page 13: ...he GX 94 s circuitry into a measure ment of gas concentration Circuit Boards The GX 94 circuit boards analyze record control store and display the information collected These circuit boards contain no user serviceable components A 3 volt coin type lithium data backup battery is located on one of these circuit boards the main CPU board in a coin type battery holder This battery assures that any sto...

Page 14: ...equires little preparation before use If you have one of the available sample drawing accessories see the Accessories section for installation instructions Starting Up the GX 94 1 Press the ON OFF INPUT button once If the Lunch Break feature is on see Setting the Lunch Break Function in the setup mode section the RESUME screen displays If the Lunch Break feature is off the Battery Voltage screen d...

Page 15: ...e in operation from the last session The Battery Voltage screen displays The Battery Voltage screen displays the minimum usable and actual battery voltage If the battery voltage is too low the GX 94 will not continue This message displays the date and time as set in Calibration Mode The following two screens display while the GX 94 checks itself for proper operation The GX 94 alerts you if a malfu...

Page 16: ...y will sound the ALARM LED will blink and O2 will flash on the display To verify detection of combustibles use a controlled source of flammable vapor for example a bottle of isopropyl alcohol The audible alarm will sound the ALARM LED will blink and HC will flash on the display Caution Do not use gas from a cigarette lighter to test response to combustibles Exposing the sensor to uncontrolled high...

Page 17: ...LOCATION Normal Operation The GX 94 will continuously monitor the ambient air and display the tar get gas concentrations present If the GX 94 is taken into a low light environment the display backlight will automatically turn on Turning Off the GX 94 To turn off the GX 94 press and hold down the ON OFF INPUT button until the display goes blank approximately five seconds then release the button ...

Page 18: ...bove the high alarm setting the alarm tone and alarm LED will be continuous 3 H2S and CO Low Alarm If the H2S or CO detected exceeds the low alarm setting a pulsed tone will sound the alarm LED will blink and H2S or CO will flash on the appropriate channel Note The H2S and CO channels do not have a high alarm 4 Short Term Exposure Limit STEL Alarm H2S and CO Only If the average toxic gas level det...

Page 19: ...F as shipped from RKI Instru ments It is user adjustable See Viewing and Setting Alarms in the setup mode section for adjustment instruc tions 7 Overscale Alarm If the full scale value is exceeded for any channel the alarm tone and LED will be continuous The display will show MAX in the gas reading field for that channel 8 Low Battery When the battery charge drops near the lower limit the GX 94 di...

Page 20: ...tery alarm 10 Sensor Failure and Emergency Operation The GX 94 continuously monitors itself for proper operation If a malfunction occurs the GX 94 alerts you with audible and visual alarms If a sensor fails during operation the GX 94 will sound a steady tone the alarm LED will be on and it will display the following screen with the failed sensor in parentheses in this example the combustibles sens...

Page 21: ...self resetting alarms see Setting the Alarm Logic in the Setup Mode section Self Resetting Alarms Self resetting alarms will automatically reset and shut off when the reading falls below or rises above for oxygen the alarm point setting Latching Alarms Latching alarms must be reset manually and cannot be reset until the gas concentration falls below or rises above for oxygen the alarm point settin...

Page 22: ... log time To enter display mode from the normal operation screen press the DIS PLAY ADJ button To scroll from one screen to the next press the DISPLAY ADJ button The screen will hold for 20 seconds before reverting to normal operation screen or until DISPLAY ADJ is pressed to go to the next screen User and Station ID Screen This function appears only when the user ID option is activated in setup m...

Page 23: ...After the correct information is entered press DISPLAY ADJ to exit this screen Peak Screen The Peak function shows the highest lowest for O2 concentrations detected since the GX 94 was turned on Peak readings stay in the instrument s memory until a higher lower for O2 level is detected or the unit is turned off When the Lunch Break RESUME option is selected during startup the the GX 94 remembers t...

Page 24: ...in the setup mode When selected at startup the Lunch Break RESUME option enables the GX 94 to continue calculating the average reading from the last operating session Elapsed Time Screen The Elapsed Time screen shows the time in minutes since the unit was turned on When the Lunch Break RESUME option is selected during start up the GX 94 will include the time from the last session when it displays ...

Page 25: ...ed off Time Weighted Average TWA Screen The TWA function shows the average reading for toxic gases during the last 8 hours If 8 hours has not elapsed since the last time the STEL TWA was cleared the average is still calculated over 8 hours with the missing time assigned a 0 value for readings When the Lunch Break RESUME option is selected during start up the GX 94 will include the TWA from the las...

Page 26: ...ully charged Ni Cd batteries typically measure 2 6V Note The GX 94 automatically checks battery voltage during start up if the measurement is below 2 3V the GX 94 will not operate Time Date Temperature Screen This function shows the current time date and ambient temperature for example The time is in military format a 24 hour clock BATTERY MIN 2 3V BATTERY NOW 2 8V Apr 25 02 21 57 TEMP 24 C 75 F ...

Page 27: ...a logger memory is cleared the Remaining Log Time will be reset and all collected data will be erased Remaining Log Time Screen The remaining log time screen shows the time remaining until the data logger memory is full The remaining time depends upon the logging frequency and how many channels are active Press DISPLAY ADJ once more to return to normal operation CLEAR DATA LOGGER YES AIR NO DISP A...

Page 28: ...ID function on or off update the time calibration setting update the data logger alarm setting update the frequency in Hz of the buzzer sound view several internal voltage values Tips for Using Setup Mode Press SHIFT to scroll down through the main menu and submenus and to lower values in a specific option Press AIR to scroll up through the main menu and submenus and to raise values in a specific ...

Page 29: ...g indicating the cursor position and that this item is currently selected 4 Scroll to the desired main menu item using the AIR and SHIFT buttons and press ON OFF INPUT to enter that item Resetting the NVRAM 1 SET DEF NVRAM DEF SET ALL Allows the user to reset all values for non volatile RAM all options are returned to default values DEF SET ALARM Resets only the alarm levels to default values DEF ...

Page 30: ...throughout all setup and normal display screens Viewing Setting Alarms 3 SET ALARM Sets the alarm levels for gases detected by the GX 94 Press AIR to change the alarm level for a single gas or DISPLAY ADJ to skip that channel Press AIR to raise an alarm level or SHIFT to lower the alarm level Hold down the button to scroll quickly through the alarm setting The lowest available setting for each ala...

Page 31: ... scroll through 0 9 A Z to select the desired character 2 Press ON OFF INPUT to enter that value and move to the next character 3 Repeat steps 1 and 2 until the last serial number character is flashing then press ON OFF INPUT to go to the END screen Setting the Temperature 5 SET TEMP Sets the ambient temperature reading 1 The temperature screen displays the current temperature reading Compare this...

Page 32: ...t to ON the user must press DISPLAY ADJ to reset the alarm after the gas reading has dropped below or risen above for oxy gen the alarm point Setting the Lunch Break Function 8 SET LUNCH Toggles the Lunch Break feature ON and OFF With Lunch Break OFF default selected the GX 94 automatically starts new TWA PEAK and AVERAGE reading collection at start up and the TIME IN OPERATION starts over at zero...

Page 33: ...is useful in environments with significant background noise and or a variety of audible signals 1 The frequency screen displays the current buzzer frequency along with a continuous tone from the buzzer 2 Press AIR to raise the frequency or SHIFT to lower 3 Press ON OFF INPUT to accept the setting and return to the main menu Displaying Circuit Voltages 13 DISPLAY VOL Displays the voltage in millivo...

Page 34: ...he setup mode section Calibration Supplies and Equipment To calibrate the GX 94 you will need Known calibrating samples of the gases to be detected The combustible and toxic sample concentrations should be approximately in the middle of the detection ranges a zero oxygen source such as 100 nitrogen is recommended for setting the O2 zero A 0 5 LPM liters per minute fixed flow regulator Note When th...

Page 35: ... the AIR button until the display indicates ZERO ADJUSTED RELEASE AIR KEY The instrument will automatically set the LEL and toxics circuits to zero and the O2 circuit to 20 9 4 Screw the adapter plate to the threaded hole in the sensor screen 5 Connect the calibration tubing from the adapter plate to the regula tor Note Do not screw the fixed flow regulator onto the cylinder at this time since sam...

Page 36: ...ibration Method This section describes calibration using the auto calibration method To calibrate using the single calibration method see Calibrating with the Single Calibration Method later in this section 1 Use the AIR and SHIFT buttons to select the AUTO CAL menu option The 1 will be flashing 2 Press the ON OFF INPUT button to continue in the auto calibra tion menu The display will ask you if y...

Page 37: ...annels and return to the Calibration Values screen Note The RKI Four Gas Cylinder contains approximately 12 O2 by volume Be sure to set the O2 auto calibration value to agree with the concentration listed on the cylinder s label not zero 8 With the Calibration Values screen displayed press the ON OFF INPUT button The gas readings will flash 9 Screw the regulator onto the calibration cylinder The g...

Page 38: ...tton to return to normal operation Calibrating with the Single Calibration Method This section describes calibration using the single calibration method To calibrate using the auto calibration method see Calibrating with the Auto Calibration Method earlier in this section CAUTION The single calibration method does not have a FAIL notification Replace sensors that cannot be set to agree with the ca...

Page 39: ...er one minute if the read ing does not correspond to the calibration gas concentration press the AIR button to increase the reading or the SHIFT button to decrease the reading The GX 94 will beep each time a switch is pressed 4 When the reading is correct press the ON OFF INPUT button The display will read HC CAL END then automatically return to the main menu 5 Unscrew the regulator from the cylin...

Page 40: ... current date and time for the GX 94 From the normal operation screen press and hold the SHIFT but ton then press the DISPLAY ADJ button to enter Calibration Mode The calibration menu will show the following screen with a flashing number indicating the cursor position 1 Use the SHIFT button to place the cursor in from of menu item 6 SET DATE TIME The number 6 will flash 2 Press the ON OFF INPUT bu...

Page 41: ...splayed in military format a 24 hour clock instead of a 12 hour clock 5 After the minutes are entered press ON OFF INPUT to return to the main menu 6 Press SHIFT to scroll to the last menu item 7 RETURN 7 Press ON OFF INPUT to return to normal operation ...

Page 42: ...d remove the cover Remove the batteries and verify that the battery compartment and electrical contacts are clean Insert fresh batteries alkaline or fully charged Ni Cd according to the polarity markings in the compartment and replace the cover Note The batteries continuously supply a bias voltage to maintain the toxic sensors even when the instrument is off see Sen sor Maintenance The power drain...

Page 43: ...logged data when the main batteries are changed Figure 3 Lithium Backup Battery 1 Take the GX 94 to a non hazardous location and turn the power off 2 Remove the four 4 phillips screws from the bottom of the instru ment Two in the belt clip and two next to the label 3 Pull the bottom and top case apart where the rubber cushion cov ers the seam This opens the entire case 4 Locate the lithium backup ...

Page 44: ... belt clip and screws Charcoal Filter The CO sensor diffusion opening is equipped with an activated carbon filter disk that includes an integral rubber boot It removes H2S and most hydrocarbons to limit interference with the CO measurement Figure 4 Charcoal Filter Replacement To replace the filter 1 Unscrew the diffusion screen retaining screw located at the rear of the unit Diffusion Screen Retai...

Page 45: ... to exposure to combustible gas but certain environ mental factors may affect duration The GX 94 sensors are easy to replace but contain no user serviceable parts For genuine RKI sensors call RKI or your local distributor All sensors are covered by a limited warranty see warranty for details Combustibles Sensor Replace the combustibles sensor when 1 The combustibles circuit cannot be calibrated co...

Page 46: ...how 00 immediately after the start up sequence and cannot be set to zero by the Demand Zero com mand Note Allow up to 1 2 hour after the toxics sensors have been replaced to show a normal response then calibrate Sensor Replacement Figure 5 GX 94 Sensors Oxygen Sensor GX 94 Shown w out Top Case H2S Sensor CO Sensor Sensor Gasket Combustible HC Sensor ...

Page 47: ...individual sensors gently unplug from the circuit board by pulling straight up 6 Carefully insert a new sensor Be sure to sure to place the sensor in the correct position sensors are not interchangeable between positions 7 Reinstall the sensor gasket on the sensors 8 Reinstall the cover belt clip and screws 9 For Oxygen CO and H2S sensors wait up to 1 2 hour for the sen sors to stabilize Combustib...

Page 48: ...easy to install and use and is built to give years of dependable service Installing the Pump 1 Slide the pump onto the sensor end of the GX 94 as shown in Fig ure 6 Figure 6 Attaching the GX 94 Pump 2 Make sure the pump retaining captive screw on top of the pump Probe Hose 10 ft Standard Pump On Off Switch Pump Battery Cover Screw Pump Retaining Screw GX 94 Pump ...

Page 49: ...to changes in the sample response time will vary with sample hose length Do not immerse the probe tip in liquids 3 The GX 94 will display gas concentrations sound alarms and log data normally 4 If the sample system probe filter hose pump is blocked or restricted the Low Flow alarm on the pump will sound This alarm is a steady tone and lit yellow LED on the top of the pump Take the GX 94 to a non h...

Page 50: ...ver b Replace the old battery with a C size alkaline or fully charged Ni Cad battery c Replace the battery cover 2 Inspect the cotton filter in the probe handle periodically Replace the cotton filter when it is visibly dirty or when it does not allow adequate flow to the pump Low Flow failure a Unscrew the probe handle b Remove and discard the clogged filter Replace with a cotton filter c Re insta...

Page 51: ... 7103RK Charcoal filter w rubber boot for CO sensor diffusion port 35 1513RK Calibration sample adapter plate 47 5000RK Downloading cable 49 1402RK Data logging backup battery 3 0 volt lithium CR2032 coin type 49 1130RK Battery size C alkaline unit requires 2 49 1230RK Battery size C Ni Cad unit requires 2 49 3100RK Ni Cad battery charger bench top for up to 8 batteries 115 VAC 49 3102RK Ni Cad ba...

Page 52: ...12 Oxy 50 ppm CO nitrogen balance 103 liter 81 0154RK 02 Calibration cylinder 4 gas 50 LEL CH4 12 Oxy 50 ppm CO 50 ppm H2S nitrogen balance 58 liter 81 1003RK Regulator for calibration kit fixed flow at 0 5 LPM no gauge for 17 34 liter cylinders 81 1004RK Regulator for calibration kit fixed flow at 0 5 LPM with gauge for 58 103 liter cylinders 81 1119RK Hand aspirated sample adapter with 10 ft hos...

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