Generator Gas Analyzer (GGA)

Instruction Manual

HA0112P01 Rev. B

UTILITY SYSTEMS

1 HA0112P01 Rev. B

ContentsSpecifications .................................................................................................................................. 4

Application ...................................................................................................................................... 5

System Description ......................................................................................................................... 6System Electronics...................................................................................................................... 6Display Panel ............................................................................................................................. 6Sensor Cell Assembly ................................................................................................................. 7

Installation ...................................................................................................................................... 8Generator Gas Analyzer Mounting ............................................................................................. 8Piping ........................................................................................................................................ 8Electrical Connections ............................................................................................................... 8Contacts .................................................................................................................................... 8Circuit Protection ....................................................................................................................... 9

System Operation ......................................................................................................................... 10GGA Initialization .................................................................................................................... 10Fn (Function) Menu ................................................................................................................. 11Cell Output Voltages ................................................................................................................ 13Generator Gas Analyzer Calibration ........................................................................................ 13Normal Operation .................................................................................................................... 14Purge Operation ....................................................................................................................... 14

Maintenance ................................................................................................................................. 15Periodic Maintenance .............................................................................................................. 15Weekly...................................................................................................................................... 15Every Six Months ..................................................................................................................... 15

Spare Parts ................................................................................................................................... 16

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FiguresFigure 1 - System Overview ........................................................................................................................ 17Figure 2 - Piping Schematic ......................................................................................................................... 18Figure 3 - System Electronics ...................................................................................................................... 19Figure 4 - Display Panel Assembly .............................................................................................................. 20Figure 5 - Sensor Cell .................................................................................................................................. 21Figure 6 - Wiring Diagram ........................................................................................................................... 22

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GENERATOR GAS ANALYZERIMPORTANT INFORMATION!

THIS EQUIPMENT OPERATES AT VOLTAGE LEVELS THAT CAN BE HAZARDOUS TO PERSON-NEL. THE SECTION ABOUT SAFETY CONSIDERATIONS SHOULD BE READ BEFORE INSTAL-LATION OR SERVICE.

THESE INSTRUCTIONS DO NOT PURPORT TO COVER ALL DETAILS OR VARIATIONS INEQUIPMENT OR TO PROVIDE FOR EVERY POSSIBLE CONTINGENCY TO BE MET IN CON-NECTION WITH INSTALLATION, OPERATION OR MAINTENANCE.

SHOULD FURTHER INFORMATION BE DESIRED, OR SHOULD PARTICULAR PROBLEMSARISE THAT ARE NOT COVERED SUFFICIENTLY FOR THE PURCHASER’S PURPOSES, THEMATTER SHOULD BE REFERRED TO ENVIRONMENT ONE CORPORATION.

GENERATOR GAS ANALYZERSAFETY CONSIDERATIONS

THE SYSTEM ELECTRONICS ENCLOSURE AND SENSOR CELL ENCLOSURE CONTAIN 120VOLTS AC. THIS VOLTAGE APPEARS AT THE AC POWER STRIP AND VARIOUS OTHERPOINTS. EQUIPMENT OPERATION INVOLVES A FLAMMABLE GAS (HYDROGEN) UNDERPRESSURE. APPROPRIATE MEASURES MUST BE TAKEN TO PREVENT LEAKS AND TOAVOID SOURCES OF IGNITION.

WHEN ALL ELECTRICAL CONNECTIONS TO THE SYSTEM ELECTRONICS, SENSOR ANDDISPLAY PANEL ARE COMPLETE AND TESTED, ENSURING THAT ALL SEALING FITTINGS AREFILLED WITH AN APPROVED COMPOUND IS NECESSARY. THIS IS A NATIONAL ELECTRICALCODE REQUIREMENT FOR CLASS 1, DIVISION 1, GROUP B ENVIRONMENTS (NEC 501-5).

ALL GAS CONNECTIONS TO THE SENSOR CELL MUST BE LEAK CHECKED PRIOR TO AP-PLYING AC POWER.

CHECK FOR LEAKS AT ALL TUBING AND MECHANICAL CONNECTIONS INSIDE THE SENSORCELL ENCLOSURE. IF LEAKS ARE FOUND, DETERMINE THE CAUSE AND REPAIR. REPEAT-ING THE LEAK CHECK UNTIL THE SENSOR CELL ENCLOSURE IS DETERMINED TO BE LEAKTIGHT IS NECESSARY.

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Specifications

Measurement Characteristics

Case Purity 70 to 100% H2 in Air

Purge 0 to 100% H2 in CO2

0 to 100% Air in CO2

Hydrogen Flow Rate 100 to 700 cc/min

Electrical Characteristics

Power 120 VAC, 50160 Hz

Outputs, Relays 30 V/1.0 A DC, 120 V/0.5 A ACAlarm, NO and NC 125 V/0.005 A resistive DCWarning, NO and NCTrouble, NO and NC (Alarm and warning levels areNormal, NO and NC adjustable)

Output, Signal 4-20 mA current output

Mechanical Characteristics

Dimensions:System Electronics Enclosure 11.00" x 12.00" x 9.25"Sensor Cell Enclosure 8.00" x 10.00" x 6.25"Display Enclosure 10.50" x 8.50" x 6.25"Valve Panel (optional) 24.00" x 24.00" x 8.00”

Temperature 30 to 125 F

Area Classification Class 1, Division 1, Group B

Hydrogen Pressure 100 psi maximum

Gas Connections 1/4" female NPT

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Application

Modern high capacity turbine generators use hydrogen gas as a cooling medium. Tworeasons for the use of hydrogen are 1) it has the best heat transfer characteristics of anygas; and 2) the low atomic weight of hydrogen makes it the lightest and, therefore, the leastdense of any stable gas (10 percent that of air at a purity of 98 percent), resulting in thelowest windage losses. Lower windage losses represent greater operating efficiency andlower cost per megawatt.

The hydrogen auxiliary system exists to maintain the quality and quantity of cooling gasrequired to ventilate the conducting and rotating parts of hydrogen cooled generators. Tooptimize generator efficiency and safety, monitoring and maintaining hydrogen purity isimportant.

Environment One’s microprocessor controlled Generator Gas Analyzer (GGA) with its triplerange sensor cell is capable of measuring 70 to 100 percent H2 in Air, 0 to 100 percent H2 inCO2 and 0 to 100 percent Air in CO2.

The GGA continuously analyzes the generator cooling gas, displays gas purity in real timeand has a corresponding 4-20 mA output. In the event that the gas purity falls to a warning oralarm level, a visual indication is given and alarm contacts are switched.

The triple range sensor cell also monitors purge gases used during generator shutdown andmaintenance. Purge gas purity is displayed and a corresponding 4-20 mA output is providedfor H2 in CO2 or Air in CO2.

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System Description

The Generator Gas GGA is designed for use on hydrogen-cooled generators. It is designedto operate in Class 1, Division 1, Group B hazardous areas. Its main purpose is to analyzeand, in real time, display the hydrogen gas purity on built-in numeric displays.

The major components of the Generator Gas Analyzer include the System Electronics,Display Panel and Sensor Cell Assembly (Figure 1).

System Electronics

The System Electronics consist of one Controller board, one Input/Output Board and fourIsolation Barriers. All are mounted in an explosion proof enclosure. Electrical connections aremade through four ¾” female conduit openings (Figure 3).

The System Electronics provide purity monitoring, calibration, mode selection, sensor unitcontrol, alarm contacts, data logging, system inputs/outputs, sensing unit linearization, anddiagnostics.

Fail-safe operation of the GGA is assured by the following:

1. On power-up the GGA must execute and pass qualifying self tests. Failure in any testresults in the termination of operation and the annunciation of the condition causing thefailure.

2. Following power-up and/or system reset, the GGA is continuously supervised by anindependent watchdog monitor that serves to reset it should its operation become erratic.

3. The GGA is completely self-supervised and continuously checks itself for legal processorfunctioning, internal voltages, analog-to-digital conversion accuracy, integrity of cabling,and relay operation. Any faults are immediately annunciated.

For further information see the section ANALYZER FAILURE.

Display Panel

The Display Panel provides control of all functions of the GGA as well as complete annuncia-tion of the status of the GGA. Functions are accessed by means of a four-button membrane-switch keypad and 16 (Function) key causes the LCD to continuously scroll the names of theavailable functions of the GGA. A function may then be accessed by pressing the Enter keywhen the function name appears. Subsequently, to signal confirmation, the function namewill flash briefly.

The Display Panel provides Light Emitting Diodes (LED’s) to annunciate the Normal (H2 inAir), Purge (H2 in CO2 and Air in CO2), and Calibrate (H2, CO2 and N2) GGA states. In addi-tion, they indicate Warning, Alarm, and Trouble conditions. A green LED indicates AC Power.It is important to understand that, should the GGA go into either Warning and/or Alarm, it willlock into continuous monitoring of the gas stream. No other function can be accessed unlessthe Alarm/Warning Reset key is pressed first.

To permit a system level initialization (“cold start”), a momentary push-button located behind

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the Display Panel (Figure 4) in the upper right hand corner may be pressed. Since all cali-bration constants are stored in non-volatile memory, these values will not be lost should thesystem be initialized or should it lose, then regain, AC power.

Sensor Cell Assembly

The sensor cell assembly is comprised of a sampling thermistor and a reference thermistor— both operated at very low power in a self-heated mode embedded in a temperatureregulated cell block. Gas purity is derived as a function of the thermal conductivity of the gasmixture to the heat output of the thermistors under known constraints. See CELL OUTPUTVOLTAGES for a detailed description of the Sensor Cell.

(Display Panel cont’d)

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Installation

The following instructions provide details to facilitate the equipment installation. The exactlocation of the Generator Gas Analyzer (GGA) should be in accordance with recommenda-tions made by the generator manufacturer or its authorized representative.

Prior to applying power to the GGA System, ensure that the local power source usedmatches the power rating on the GGA nameplate.

All gas lines must be connected to the GGA Sensor Cell and leak tested beforecontinuing.

CAUTION! Care must be taken when removing the cover to avoid damage (scratches,etc.) to the sealing surfaces of the cover and enclosure. Do not remove the coverfrom the enclosure unless power is removed from the System Electronics and thesystem is free of hydrogen.

Generator Gas Analyzer Mounting

The location chosen should be such that the equipment will not be subjected to extremes ofdust, temperature, vibration or shock. It should be accessible for service, with adequateclearance. Fasteners used should be compatible with the mounting surface to support theweight of the enclosures. Refer to figures 3, 4 and 5 for mounting dimensions.

Piping

Piping should be in accordance with Figure 2. All three calibration gases (hydrogen, carbondioxide and nitrogen) should be at the same pressure as the generator case pressure. Gasconnections are made through two 1/4" NPT fittings provided at the bottom of the SensorCell enclosure. All piping should be pressurized and leak tested prior to operation.

Electrical Connections

Electrical connections are made through four 3/4" male conduit unions provided at thebottom of the System Electronics enclosure (Figure 3). System power requirement is 120VAC, 50/60 Hz. The source of AC power should be reliable and not subject to severe tran-sients.

To gain access to the inside of the System Electronics enclosure for electrical connections,the threaded cover needs to be removed.

Wiring and wire routing should be in accordance with Figure 3 so that noise generated fromthe AC power and contacts does not interfere with the signals.

Contacts

As shown in Figure 6, the GGA provides the following relay contacts:

• Warning Relay Both a normally open and a normally closed contact (single pole, doublethrow configuration) is provided and a Warning is signaled by an energized relay.

• Alarm Relay Both a normally open and a normally closed contact (single pole, doublethrow configuration) is provided and an Alarm is signaled by an energized relay.

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• Trouble Relay Both a normally open and a normally closed contact (single pole, doublethrow configuration) is provided and Trouble is signaled by a de-energized relay.

• Normal Relay Both a normally open and a normally closed contact (single pole, doublethrow configuration) is provided and Normal is signaled by an energized relay.

Circuit Protection

A 1/2-amp slo-blow fuse is used to provide circuit protection and is located on the Input/Output PCB (Figure 6).

(Contacts cont’d)

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System Operation

GGA Initialization

With system power on, press the RESET pushbutton on the backside of the DISPLAYPANEL (Figure 4).

The GGA will perform several self tests and, if successful, the DISPLAY PANEL will respondwith (a) all discrete LED’s lit; (b) all segments and the tenths place decimal point of the GASPURITY display lit; and (c) all pixels of the LCD display on. Within several seconds (a) alldiscrete LED’s, except the AC POWER and TROUBLE LED’s, will turn off; (b) all segments,except the tenths place decimal point of the GAS PURITY display will turn off; and (c) thedisplay will indicate LINKING … as the DISPLAY PANEL initiates communication with the restof the system. Communication should be established within several seconds and the LCDdisplay will then echo the results of cold start initialization:

• GGA ANALYZER READY

• INITIALIZING …

• 12 BIT ADC …

• … CALIBRATED Note: If calibration is unsuccessful then the LCD will display 12 BITADC ERROR. After annunciating TROUBLE, the processor will be stopped because, atthis point in the start-up sequence, this condition is a fatal error.

• 8 BIT ADC …

• … CALIBRATED Note: If calibration is unsuccessful then the LCD will display 8 BIT ADCERROR. After annunciating TROUBLE, the processor will be stopped because, at thispoint in the start-up sequence, this condition is a fatal error.

• lout SET TO 4 mA where Iout is the 4-20 mA GGA output. See below.

• Tcell = XX.X OC (where XX.X is the instantaneous cell block temperature). For an inde-terminate period (normally not exceeding 15 minutes for a cold start) the LCD will displaythe real-time temperature of the sensor cell block. When the temperature rises to 55.0 C+/- 0.5 C, the system will advance and the display will then indicate:

• ANALYZER READY After this last message, all discrete LED’s will go out except ACPOWER and TROUBLE. In response to the prompts NORMAL (H2/AIR), CONFIGUREVALVES, allow the sample gas to flow through the sensor then press the ENTER key.This is the NORMAL mode of operation. See NORMAL for more information.

For a first time installation, it is essential that a gas sensor calibration be performedon the GGA system. Also, the faults log should be cleared. See SYSTEM, below.

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Fn (Function) Menu

The following items are available by pressing the Fn key:

• NORMAL (H2/AIR) This item, when displayed, can be selected by pressing the ENTERkey. See NORMAL OPERATION for more information.

• PURGE This item, when displayed, can be selected by pressing the ENTER key. Seethe description PURGE OPERATION for more information.

• GAS CALIBRATION This item, when displayed, can be selected by pressing the ENTERkey. See GENERATOR GAS ANALYZER CALIBRATION for more information.

• SETTINGS This item, when displayed, can be selected by pressing the ENTER key. Ifselected, ALARM LEVEL and WARNING LEVEL will be displayed.

These sub-items permit adjustment of the levels at which system alarm and warning areannunciated. To adjust the alarm level press the ENTER key when this sub-item appears.The LCD will display the current purity level (in percent purity) at, or above which, the systemwill annunciate an alarm condition. This value can be adjusted by using the UP arrow andDOWN arrow keys, between 80 percent and 1 percent less than the setting for the warninglevel. The new level ran be selected by pressing the ENTER key. The new level will not beselected if the Fn key is pressed instead.

To adjust the warning level press the ENTER key when this sub-item appears. The LCD willdisplay the current purity level (in percent purity) at, or above which, the system will annunci-ate a warning condition. This value can be adjusted by using the UP arrow and DOWN arrowkeys between 1 percent more than the setting for the alarm level and 99.9 percent. The newlevel can be selected by pressing the ENTER key. The new level can be selected by press-ing the ENTER key. The new level will not be selected if the Fn key is pressed instead. Thesystem will not permit the alarm and warning levels to have the same value; it will also notpermit the alarm level to be higher than the warning level.

• SYSTEM. This item, when displayed, can be selected by pressing the ENTER key. Ifselected, five sub-items will be displayed: MONITOR Tcell, SHOW FAULTS LOG, CLEARFAULTS LOG, RUN DIAGNOSTICS and SHOW PROGRAM ID. Pressing the ENTERkey when a sub-item appears selects that sub-item.

• Selecting the sub-item MONITOR Tcell permits a real-time readout of the temperature ofthe gas sensor cell. Press the Fn key to terminate.

The GGA is a self-supervised system and can identify and trap detected faults in its opera-tion. Whenever a fault is detected the TROUBLE LED is illuminated, the TROUBLE RELAYis de-energized, and a description of the fault is logged (stored and latched). Faults can bedisplayed by pressing the ENTER key when the sub-item SHOW FAULTS LOG is displayed.Fault conditions that can be detected include errors in the system’s 8- and 12-bit analog-to-digital converters, power supply voltages, supervisory loop errors and gas sensor cell blocktemperature. Press the Fn key to terminate.

The faults log can be erased by pressing the ENTER key when the sub-item CLEARFAULTS LOG is displayed. If selected, the LCD will prompt CLEAR LOG? Press the ENTERkey to clear all logged faults. Once executed the display will indicate LOG CLEARED forapproximately two seconds and then go blank, leaving the system in the NORMAL mode.

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Pressing the Fn key instead will blank the display and place the system in the NORMALmode without clearing the faults.

Pressing the ENTER key when the sub-item RUN DIAGNOSTICS is displayed permits areadout of the GGA’s initial cell reference voltage, the output voltages of all power supplies,tests the systems NORMAL, TROUBLE, ALARM and WARNING relays, and the MembraneKeypad on the DISPLAY PANEL. At any point press Fn to terminate testing. The test se-quence is:

1. The LCD will display Vref=X.XXXVDC. This parameter is the voltage of the cell referencethermistor and was stored at the time of the last calibration of the cell (whether H2, CO2

or N2).

2. The LCD will display Vh2=X.XXXVDC. This parameter is the voltage of the hydrogencalibration constant and was stored at the time of the last calibration of the cell.

3. The LCD will display Vco2=X.XXXVDC. This parameter is the voltage of the carbondioxide calibration constant and was stored at the time of the last calibration of the cell.

4. LCD will display Vn2=X.XXXVDC. This parameter is the voltage of the nitrogen calibrationconstant and was stored at the time of the last calibration of the cell.

5. The LCD will display Vadc> X.XXVDC. This parameter is the reference voltage of the 12bit analog-to-digital converter and will range between 3.97 and 4.22 VDC.

6. The LCD will display +5V> X.XXVDC. This parameter is the output of the +5 volt digitalsupply and will range between 4.50 and 5.50 VDC.

7. The LCD will display +12V> XX.XVDC. This parameter is the output of the +12 volt digitalsupply and will range between 10.8 and 13.2 VDC.

8. The LCD will display +15V> XX.XVDC. This parameter is the output of the +15 voltanalog supply and will range between 13.5 and 16.5 VDC.

9. The LCD will display -15V> XX.XVDC. This parameter is the output of the -15 volt analogsupply and will range between -13.5 and -16.5 VDC.

For the above voltages, the LCD will flash the message ERROR alternately with the voltage if themeasured voltage is out of limit.

10. The LCD will display RELAY TEST … The system will cause each relay to be energized.If no errors are detected, the LCD will display RELAYS PASS. If an error is detected, theLCD will display RELAYS FAIL, FAILURE IN, and then either NORMAL RELAY, TROUBLERELAY, ALARM RELAY or WARNING RELAY.

11. The LCD will display KEYPAD TEST … Press each key on the Membrane Keypad on theDISPLAY PANEL, reserving the ENTER key for last (this key terminates the test). Aseach key is pressed, the LCD echoes the name of the key.

Program instructions for the microcontroller within the GGA system are stored in Read-OnlyMemory (ROM) chips located within the system. The program identification and revisionlevel, in the format P_GGA Rev. X.X, can be displayed by pressing the ENTER key when the

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sub-item “SHOW PROGRAM ID” is displayed. Pressing the Fn key terminates this item.

REMINDER! Should the system go into TROUBLE, access the menu items SHOWFAULTS LOG and RUN DIAGNOSTICS for more information.

Cell Output Voltages

The sensor cell is principally comprised of a sampling thermistor and a reference thermistorembedded in a temperature regulated cell block. The voltage derived from the referencethermistor (this voltage is displayed as cr) is used to compensate for any non-purity relatedvariations in the voltage output of the sample thermistor (this voltage is displayed as s).When a cell is calibrated the value of cr is stored in non-volatile memory as the parameterVref. Subsequently, during normal operation, the real time value of cr is mathematicallycombined with Vref to form a term compensating s. This operation assures long term mea-surement accuracy of the sensor cell.

The output voltages of these thermistors can be viewed directly (i.e., prior to any computa-tion) in real time by pressing the UP arrow. This information is updated every half second andis displayed in the format S=X.XXX cr=X.XXX, where, again, s stands for the sample ther-mistor voltage and cr stands for the current value of the reference thermistor voltage. Thedisplay of these voltages may be cancelled at any time by pressing the DOWN arrow. Theparameter Vref is displayed during calibration and diagnostics.

Generator Gas Analyzer Calibration

Press the Fn (Function) key on the GGA. Wait until the display scrolls to the prompt GASCALIBRATION then press the ENTER key. The display will scroll the prompts CALIBRATEH2, CALIBRATE CO2 and CALIBRATE N2. When the display scrolls to the prompt CALI-BRATE H2, press the ENTER key. In response to the prompts CALIBRATE H2, CONFIGUREVALVES, permit the hydrogen calibration gas to flow through the sensor. With the calibrationgas flowing the LCD will display the voltage output of the reference cell sensor in the formatVref=X.XXX VDC. If it is desired to cancel the calibration at this point, press the Fn key; thiswill permit a return to the main menu. If it is desired to continue the calibration, observe thereference voltage and, if it appears stable (i.e., a final change of not greater than 1 mV perminute) press the ENTER key.

The LCD will display the voltage output of the sample cell sensor in the format“Vcell=X.XXXVDC”. Again, the calibration may be terminated by pressing Fn. If it is contin-ued, observe the sample cell voltage as it adjusts to the flowing H2 calibration span gas.When it appears stable (i.e., a final change of not greater than 1 mV per minute, whichoccurs within approximately 15 minutes) press the ENTER key. The LCD will display H2

CALIBRATED. This concludes the H2 calibration.

The display will scroll the prompts CALIBRATE H2, CALIBRATE CO2 and CALIBRATE N2.Press the Fn (Function) key on the GGA to return to the main menu or, else, to continue gascalibration, wait until the display scrolls to the prompt CALIBRATE CO2 and press the EN-TER key. In response to the prompts CALIBRATE CO2, CONFIGURE VALVES, permit thecarbon dioxide calibration gas to flow through the sensor. With the calibration gas flowing,the LCD will display the voltage output of the reference cell sensor in the format Vref=X.X-XXVDC. If it is desired to cancel the calibration at this point, press the Fn key; this will permit areturn to the main menu. If it is desired to continue the calibration, observe the referencevoltage and, if it appears stable (i.e., a final change of not greater than 1 mV per minute),press the ENTER key.

(Function Menu cont’d)

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The LCD will display the voltage output of the sample cell sensor in the format Vcell=X.XXXVDC. Again, the calibration may be terminated by pressing Fn. If it is continued, observe thesample voltage as it adjusts to the flowing CO2 calibration zero gas. When it appears stable(i.e., a final change of not greater than 1 mV per minute, which occurs within approximately15 minutes) press the ENTER key. The LCD will display CO2 CALIBRATED. This concludesCO2 calibration.

The display will scroll the prompts CALIBRATE H2, CALIBRATE CO2 and CALIBRATE N2.Press the Fn key on the GGA to return to the main menu or, else, to continue gas calibration,wait until the display scrolls to the prompt CALIBRATE N2 and press the ENTER key. Inresponse to the prompts CALIBRATE N2, CONFIGURE VALVES, permit the nitrogen calibra-tion gas to flow through the sensor. With the calibration gas flowing the LCD will display thevoltage output of the reference cell sensor in the format Vref=X.XXX VDC. If it is desired tocancel the calibration at this point press the Fn key; this will permit a return to the mainmenu. If it is desired to continue the calibration, observe the reference voltage and, if itappears stable (i.e., a final change of not greater than 1 mV per minute), press the ENTERkey.

The LCD will display the voltage output of the sample cell sensor in the formatVcell=X.XX,X’VDC. Again, the calibration may be terminated by pressing Fn. If it is continued,observe the sample voltage as it adjusts to the flowing N2 calibration zero/span gas. When itappears stable (i.e., a final change of not greater than 1 mV per minute, which occurs withinapproximately 15 minutes), press the ENTER key. The LCD will display N2 CALIBRATED.This concludes N2 calibration.

Press the Fn (Function) key to return to the main menu.

This concludes the gas sensor calibration of the GGA system.

Normal Operation

Normal operation of the GGA system can be accessed by first pressing the Fn key to accessthe main menu and, then, pressing the ENTER key when the display scrolls to the promptNORMAL (H2 in AIR). In response to the prompts NORMAL (H2/AIR), CONFIGURE VALVES,permit the sample gas to flow through the sensor then press the ENTER key. In the NOR-MAL mode of operation the GGA can respond to both WARNING and ALARM levels. Bothlevels are programmable (see SETTINGS for detailed information). The 4-20 mA currentoutput of the GGA corresponds to 70 percent to 100 percent gas purity and the GGA mustremain below the WARNING or ALARM level for a minimum of one minute to generate analarm. Should the GGA go into WARNING it will energize the WARNING RELAY (Figure 6),and illuminate the WARNING LED. Further system operation is locked out until theWARNING RESET key is pressed, at which point the GGA will revert to NORMALoperation.

Purge Operation

To monitor a purge operation, first press the Fn key to access the main menu, then pressENTER when the display scrolls to the prompt PURGE (H2 in AIR) or PURGE (AIR in CO2)key. In response to either the prompt PURGE (H2/AIR) or PURGE AIR/CO2, CONFIGUREVALVES, permit the sample gas to flow through the sensor then press the ENTER key. Thedisplay panel will respond with the corresponding PURGE (H2 in CO2) or PURGE (Air in CO2)LED illuminated. In this mode the 4-20 mA current output of each GGA corresponds to 0 to100 percent gas purity. There is no alarm level for either of the PURGE operations.

(GGA Calibration cont’d)

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Maintenance

Periodic Maintenance

The Generator Gas Analyzer is designed for reliable, trouble-free operation and ease ofperiodic checks and maintenance.

Weekly

1. Check and adjust, if necessary, the GGA flow rates.

2. Visually inspect the moisture indicators. Blue media indicate dry hydrogen, while pinkmedia indicate excessive moisture in the hydrogen gas sample that may affect thestability of the Generator Gas Analyzer. Replace or regenerate the Moisture Indicator andreplace the Gas Purifier if the media are pink.

3. Blow down drip leg.

Every Six Months

1. Calibrate GGA. See Generator Gas Analyzer Calibration.

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Spare Parts

Part Number Description Quantity

HC0021G02 Sensor Cell Assembly 1

HD0039G01 Controller Board 1

HD0043G01 I/O Board 1

HD0035G01 Display Board 1

HB0026G01 Display Panel 1

GA0109P03 Power Supply, +/- 15 VDC 1

HA0027P01 Power Supply, 12 VDC 1

HA0045P02 Isolation Barrier, Dual 2

HA0045P01 Isolation Barrier, Single 2

HA0038P01 Fuse, 1/2 Amp, Slo-Blow 1

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Figure 1 - System Overview

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Figure 2 - Piping Schematic

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Figure 3 - System Electronics

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Figure 4 - Display Panel Assembly

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Figure 5 - Sensor Cell

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Figure 6 - Wiring Diagram

Environment One Corporation2773 Balltown RoadNiskayuna, New York USA 12309–1090

Tel: (01) 518.346.6161FAX: 518.346.6188

www.eone.com

A PCC Flow Technologies, Inc. Company