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1. External Autocalibration Figure 2 5 Sample gland plate with external auto calibration Table 2 1 Sample ports Transducer Sample Inlet Sample Outlet High cal gas Internal Paramagnetic c NPT V4 NPT c NPT c NPT autocal only female female female female Standard Paramagnetic c NPT Va NPT N A N A female female Zirconia C OD male 4 NPT N A N A female Gfx C OD male 74 NPT N A N A female 2 1 16 External filter An external filter stainless steel may be fitted to the inlet of either Zirconia sensors or Infrared benches In which case the inlet connection will be 1 8 swagelok compression 2 12 2 2 2 2 1 Electrical Overview Power distribution Mains power Refer to figure 6 4 Electrical power enters the analyser via an IEC CE22 connector 9 This connector provides an ON OFF switch filtering and mains voltage selection as well as fusing Power is taken on to the Motherboard 20 via a 4 way connector 11 Mains power is distributed on the Motherboard to the transformer 17 via a 4 way connector 12 and to the switched mode power supply 19 which plugs directly into the Motherboard Transformer The transformer has split primary windings allowing voltage selection between 85 to 132V ac or 170 to 264V ac The transformer provides power for the gas sensor modules and a
2. Figure 6 18 High Sensitivity Gfx optical cell assembly 6 42 6 35 Gfx optical windows cleaning and replacement 6 36 Removal Refer to figure 6 16 a Remove the transducer from the 4100 chassis see section 6 30 b Remove the cell assembly see section 6 32 c Remove the detector scrubber 5 and the detector box 22 by loosening the three fixings 21 Remove the flange screws 14 which also holds the detector box lid with nuts 20 Carefully remove the window 17 and o rings 18 from the cell end d Clean the windows with a soft tissue The tissue may be moistened with acetone or an aqueous detergent may be used to help cleaning If necessary replace the windows e Whilst the windows are off inspect the inside surface of the cell and clean if necessary see section 6 36 Refitting a Inspect the window o rings and replace if necessary Re assemble as above in reverse order using a new detector scrubber b Replace the chopper box scrubber once reassembled see section 6 31 b CAUTION The chopper box 3 and detector light pipe 19 are sealed enclosures Once opened a new scrubber must be fitted c Replace the transducer into the 4100 chassis in the same position see section 6 30 d Setup and calibrate according to section 6 41 Gfx cell cleaning and replacement Refer to figure 6 16 Removal OOTD xe e a Ss rea D Remove the transducer
3. 0 Sate BE OPTIONAL BYPASS FLOWMETER SAMPLE o INLET F 0 4 RESTRICTOR 2 8 0 50 RESTRICTOR gy aupLE 1 FLowweTER Tl 2 sc OPTIONAL SAMPLE FLOWMETER 00703 OR 00704 2 1 15 Sample connections WARNING The sample and calibration gases supplied to the instrument may be toxic or asphyxiant Verify that connections are leak free at full operating pressure before proceeding with admitting toxic samples Instrument vent gases may also be toxic or asphyxiant and should be treated accordingly They should not be vented into an enclosed area The instrument is not suitable for operation with flammable or corrosive gas samples Before performing any service operation ensure that the instrument sample system has been flushed with inert gas before opening sample connections This is to prevent accidental exposure to toxic or Sample and calibration gases pass into and out of the chassis via a gland plate mounted on the rear of the chassis The versionof the gland plate will depend on which auto calibration option has been supplied Pressure or flow driven non autocalibration units The sample gland plate without autocalibration is shown in figure 2 3 This provides up to four sample inlets and a corresponding outlet for each inlet A single sample inlet is provided for each gas stream Pressure or flow driven internal
4. Remove zirconia gas sensor module see section 6 20 b Disconnect wiring from terminal block TB1 on 00700 902 zirconia control module PCB 3 c Loosen two off Zirconia cell housing 2 fixing screws 1 d Detach the cell sample connector 4 from the restrictor assembly T figure 6 11 1 Detach the viton tube from the vent port on the side of the cell sample connector 4 e Slide zirconia cell housing including check valve assembly if fitted side ways and lift to remove f The zirconia cell 6 has two flats for spanners 5 24 one at each end Anchor the zirconia cell using spanner flat 24 and undo nut 23 CAUTION If the zirconia cell is not anchored with the correct spanner flat the cell will be destroyed 9 Anchor the zirconia cell using the other spanner flat 5 and undo the reference side nut 8 h Remove nut and gauze from the reference side of the cell 8 and 9 on i Lift Zirconia cell from spring mounting clip 7 Refitting Use reverse procedure When refitting nut 8 use spanner flat 5 on the zirconia cell Connections to from the zirconia cell to terminal block TB1 on the 00700 902 zirconia control board are shown in figure 6 13 NOTE When refitting zirconia cell sample connector nut 23 use zirconia cell spanner flat 24 to anchor the zirconia cell 6 This union must be leak tight Leaks will cause a high oxygen reading Refer to section 6 23 1 for set up and the
5. ee fic Figure 6 23 Flow driven Gfx sample pipework 6 53 6 42 6 43 6 54 Pressure driven Gfx sample pipework a Slacken off three nuts 1 on T piece restrictor assembly 4 b Note direction of on restrictor assembly 4 c Carefully pull out the sample pipework and remove the restrictor assembly 4 d Slacken off the connector at the rear of the chassis amp remove the sample inlet pipe 2 e Follow the same method for the outlet pipe which is connected viaa straight union connector Refitting a Use reverse procedure ensuring arrow on restrictor assembly 4 is pointing in the direction of the sample flow as before Flow driven Gfx sample pipework Slacken off two nuts 1 on connector 4 b Carefully pull out the sample pipework and remove the connector 4 Slacken off the connector at the rear of the chassis amp remove the sample inlet pipe 2 d Follow the same method for the outlet pipe Refitting a Use reverse procedure SECTION 7 SOFTWARE MAINTENANCE LIST OF CONTENTS Section Page 7 1 Software Upgrade Installation aaa 7 3 7 2 Software Configuration Menu 2 7 5 7 3 Definitive Calibration of Gfx AA 7 8 7 4 Recording the Base Offset of External Inputs 740 LIST OF FIGURES Figure Page TA AMICFOBIOCESSOF board AAP AA 7 3 7 2 Instrument configuration menu map 000 0 eee eee eee 7 5 7 3 S Number co
6. f Remove the earth wire 86 Remove the three signal processing PCB shielding box retaining screws 37 and remove the shielding box 38 Remove the three PCB retaining screws 39 and lift out the PCB and cables Refitting a Check that the correct value of the gain resistor R14 is in position on the new PCB Table 6 2 lists the correct resistor size and Servomex part number Table 6 2 Gfx gain resistor sizes Version R14 1210 701 CO 470R 2624 0655 1210 731 CO 1k5 2624 0770 O 1210 741 N O 1k3 2623 0762 1210 751 CH 1k5 2624 0770 Reassemble as above in the reverse order Replace the transducer into the 4100 chassis in the same position see section 6 30 CAUTION Ensure that the correct cables are fitted to the correct sockets before applying power see figure 6 20 d Setup and calibrate according to section 6 41 PE 5 Do EN ao O OQO Joog p O TO SOURCE TO CHOPPER BOX TO SIGNAL PROCESSING PCB MAST CONNECTOR AUX POWER TO 4100 CONNECTOR TO 4100 Figure 6 20 Gfx 1210 House keeping PCB assembly 6 41 Gfx set up and calibration Refer to figure 6 20 Ensure LK1 and LK2 items 8 9 on the house keeping PCB 1210 903 are configured for the correct transducer site location The latter is determined by the plug position on the multiplexer PCB 4000 924 1 in figure
7. Switched mode power supply Refer to figure 6 4 Removal a Remove cover see section 6 1 b Loosen fixing screw 18 c Pull power supply 19 directly upwards out of card guides Refitting a If replacing power supply fit fixing screw 18 from original power supply to new power supply b Refit cover Transformer Refer to figure 6 4 Removal a Remove cover see section 6 1 b Remove power connector 9 without disconnecting from Motherboard c Remove power supply 19 see section 6 9 d Disconnect transformer 17 primary connector 12 and secondary connector 13 e Disconnect transformer earth lead from earth stud 22 Remove two transformer fixing screws 15 and two washers 16 from underside of chassis Refitting Use reverse procedure 6 12 NOTE Ensure that all protective earth connections are secure prior to refitting the cover Figure 6 4 Card frame transformer and IEC appliance adaptor 6 11 Powerconnector Refer to figure 6 4 Removal a Remove two power connector fixing screws 8 and partially withdraw power connector from rear of chassis to allow access to Motherboard connection 11 b Remove earth lead from earth stud 22 c Remove connector 11 d The power connector may now be removed from the chassis Refitting Refer to figure 6 4 Use reverse procedure NOTE If fitting a new power connector use the fuse from the original power conne
8. The gain of the heater controller from IC3 pin 14 is approximately 5W V and the gain from the thermocouple to the heater is approximately 11W V Cell Signal Amplifier The cell is connected to an instrumentation amplifier IC9 which can be set toa gain of 1 or 10 The output of the instrumentation amplifier is referenced to IC9 pin 10 This voltage is controlled by IC2 pin 8 which allows the cell offset voltage to be removed by adjusting RV3 An external variable resistor connected to TB1 can also be used to remove the cell offset voltage The cell amplifier can be linked to have a bipolar output where the air point is at zero voltage output The amplifier can also be linked to have a unipolar output where the air point is set to a positive bias voltage The air point reference is available on PL2 pin 13 so that a differential measurement can be made to remove any variation in the bias voltage The output buffer can be linked to have a gain of 1 or 2 3 Installation and Configuration The Board is mounted using the four corner fixing holes Signal and power connections are made via the 20 way MAST and the power Mast connectors respectively Flying leads from the zirconia cell are connected at the terminal block TB1 Care must be taken in the relative positioning of the Board and the cell The cell electrode temperature may be as high as 730C under normal operating conditions and this will produce heating of the local environment and r
9. A terminal block which is accessible from the rear of the chassis is provided for connection of external current inputs with validation signals range change input autocal initiate input Terminal board Between one and four Terminal boards may be fitted The isolated current outputs and relays from the Sensor interface board and option boards are connected to the Terminal board via the Mother board The Terminal board presents these signals on a two part connector at the rear of the chassis Filtering is fitted to each of these connections for EMC Each Terminal board is fitted with two small pieces of conductive gasket to provide an RF connection to the chassis this is again for EMC SECTION 3 GAS SENSOR MODULE TECHNOLOGY OVERVIEW LIST OF CONTENTS Section Page 3 1 Pm 1156 Transducer Module naa eee T ie TA TA KNA Pewee es 3 3 32 Gfx 1210 Transducer Module 22 0 eecesnce ieee ones KALAN 3 6 3 3 Zirconia Transducer Module saa aa kadyd manG Hand weaves Shea acme ete 3 11 LIST OF FIGURES Figure Page 3 1 1156A Paramagnetic transducer schematic diagram 3 3 3 2 Gfx 1210 transducer schematic diagram aaa 3 6 3 3 Zirconia cell cross section Xa cee eee rues KAG ree Cee TA ee 3 11 3 1 3 2 NOTES 3 3 1 GAS SENSOR MODULE TECHNOLOGY OVERVIEW Pm 1156 transducer module 3 1 1 Principal of operation Light Source Photocells 7 Figure 3 1 1156A Paramagnetic transducer schematic di
10. Correct where necessary and re validate instrument performance If there is only one output board the Sensor Interface PCB or the fault lies within the first output board then replace the Sensor Interface PCB and or its associated terminal PCB and re validate instrument performance If the fault is located on one of the remaining optional output boards then replace the faulty output PCB and or its associated terminal board and re validate instrument performance Replace the microprocessor PCB and re validate instrument performance Note Replacing the microprocessor PCB will require reconfiguration of the analyser Refer to section 7 2 Check electrical continuity between the output boards and the associated terminal boards via the instrument motherboard connectors Replace the mother board PCB if this is faulty and re validate instrument performance Replace the motherboard PCB and re validate instrument performance 5 11 5 2 9 No response to range change input 5 12 Symptoms Analogue output ranges do not change when range 2 is selected via external contact closure Measurements and Diagnosis a Check that the analogue output assignments are correctly configured and enabled within the instrument software Check that the range 1 and range 2 assignment ranges are not identical Correct where necessary and re validate instrument performance Check that connecting wiring is correctly installed to pins within the screw te
11. 10 and 12 on connector PL1 on the transducer house keeping PCB If these are incorrect then the fault may lie within either the Multiplexer PCB or the Signal Interface PCB Correct or replace where necessary and verify instrument performance If none of the above tests have identified a problem then replace the transducer and verify instrument performance 5 4 4 Measurement faults Symptoms Unable to perform zero calibration Unable to perform span calibration Calibration failure fault indicated Low instrument sensitivity Poor instrument accuracy Measurements and Diagnosis a Verify contents of the calibration gas samples have been correctly entered into the instrument software and that calibration gases are correctly connected Check that calibration gas supply is not exhausted Increase the calibration tolerance if necessary Correct or replace where necessary and perform instrument calibration to verify performance Check that the concentration of the calibration sample corresponds with the concentration specified in the autocalibration configuration Perform a ONE CYCLE autocalibration to clear the fault Verify correct operation of autocalibration valves if fitted Perform a leak test to verify cross seat leakages Correct fault in accordance with section 5 2 12 if necessary Correct or replace where necessary and perform instrument calibration to verify performance Verify that there are no leaks in the internal pip
12. 6 38 S1210923 KIT I R SOURCE See section 6 31 51210996 KIT 1210 FUSES S1210997 KIT OPTICAL WINDOWS See section 6 35 S1210998 KIT OPTICAL MIRROR See section 6 34 S1210999 0999 KIT MOTOR ASSEMBLY See section 6 32 S2000902A PROCESSOR BOARD Figure 6 4 6 Does not include firmware S2000906A 2 MA 2 RELAY PCB Figure 6 4 2 3 4 S2000924 SENSOR INTERFACE PCB Figure 6 4 7 4000423 CALIBRATION MANIFOLD Supplied complete S4000651F 4000 SPARE SOFTWARE 4 3 S4000901 MOTHERBOARD 3 OPTION Figure 6 9 9 S4000903 KEYPAD PCB Figure 6 2 21 S4000904 TERMINAL BOARD Figure 6 9 6 S4000907 EXT AUTOCAL P C B ASSY S4000911 MOTHERBOARD 1 OPTION Figure 6 9 9 S4000924 MULTIPLEXER PCB 4 TX Figure 6 4 1 4000932 DISPLAY RIBBON ASSY Figure 6 2 24 Includes lamp 4000933 KIT KEYPAD RIBBON CABLE Figure 6 3 2 includes ribbon cable clamps 9 and grommet 7 S4000934 RIBBON CABLE ASSY MODULE S4000935 MODULE POWER CABLE ASSY kr S4000936 MAINS CABLE FORM ASSY Figure 6 4 9 11 4000975B VITON TUBING REFURB KIT Includes fittings and adaptors S4000976 KIT FEET TIP UP GREY four feet with fixing screws S4000977 KIT FUSE PCB Includes 5 off T 500 mA for F2 on rear of chassis 20 off 5A PCB fuses Figure 6 8 2 for F1 to F8 on Multiplexer board S4000978 KIT FUSE MAINS 170 264V 10 off 3 15A 20mm T HBC S4000979 KIT FUSE MAINS 85 132V 10 off 5 0A 20mm T HBC 54000
13. 6 4 to which the transducer is connected The links settings for the appropriate transducer site are given in table 6 3 6 49 6 50 Table 6 3 Gfx site location link settings Plug on multiplexer POB Hullo Poe ww k sessa Adjust the infrared source voltage by setting SW1 item 5 on 1210 903 to position 5 2 0v WIT gt gt j j CAUTION Ensure that the correct source voltage is set before operation A higher voltage setting will reduce source lifetime Switch on the power to the 4100 Check that Power OK LED D15 on the house keeping PCB 1210 903 is lit Preliminary Checks Source operation check a Check the voltage across the outer two pins of PL1 is 1 98v to 2 02v b Check that Source OK LED D11 on the house keeping PCB 1210 903 is lit Chopper motor operation check C Check that Motor OK LED D13 on the house keeping PCB 1210 903 is lit Signal processing operation check d Check that the Bench OK LED D16 on the house keeping PCB 1210 903 is lit e Remove the chopper box insulation Connect a scope to TP1 wrt TP5 on the signal processing PCB 1210 902 The trace should be stable and look like the trace shown in figure 6 21 0 4 0 2 0 2 0 4 Figure 6 21 Typical Gfx signal trace Signal level adjustments Detector Signal a Vatt and V gag b c Connect a DVM ve lead to TP5 OVA on the signal processing PCB 1210 902 Con
14. AND STANDARD RANGES Sensor Type Sensitivity Gas Range vpm 1210 701 High CO 0 50 1210 731 High CO 0 10 1210 741 High 0 50 1210 751 High CH 0 50 The description which follows uses carbon monoxide as an example only Everything stated applies equally to the carbon dioxide CO nitrous oxide N O and methane CH measurements Like most pollutant gases carbon monoxide CO absorbs electromagnetic energy in the infrared spectrum The amount of the IR absorbed provides a measurement of the CO in the sample Sensors utilising a band pass optical filter to select the wavelengths absorbed by CO are well known for the measurement of percentage level CO samples Their effectiveness for measuring low vpm levels of CO have been limited by the following factors ni o Figure 3 2 Gfx 1210 transducer schematic diagram 1 Cross sensitivity to other IR absorbers Other gases in the gas stream such as H O and CO also absorb IR energy at the same energy wavelengths as CO This results in a cross sensitivity effect 2 Drift Instability in the IR source and detection and contamination of the sample cell result in changes in the transmitted IR energy measured This baseline instability is observed as drift in the measured CO value The gas filter correlation technique resolves the weaknesses inherent in more traditional IR absorption sensors These weaknesses including drift and cross sensitivity are effectivel
15. QuickStart manual for calibration instructions 6 29 6 25 Purity paramagnetic gas sensor module Removal Refer to figure 6 4 Figure 6 14 Purity paramagnetic gas sensor module 6 30 Remove cover see section 6 1 Disconnect gas sensor module signal cable from Multiplexer board connector 23 Disconnect gas sensor module power cable from Multiplexer board connector 24 Note It may be necessary to lift the Multiplexer board 1 out of its card guides to gain access to the power cable connection All other connections to the Multiplexer board may be left connected during this operation Refer to figure 6 14 d e Disconnect sample tubing 22 23 from cell connectors 4 5 Identify inlet and outlet for ease of re connection Remove four off gas sensor module cover fixing screws 1 and remove cover 2 6 26 6 27 f Loosen four off gas sensor module fixing nuts 82 The gas sensor module oven insulation will need to be displaced not removed during access to the fixing nuts 9 Slide gas sensor module sideways and lift to remove Refitting Use reverse procedure Refer to QuickStart manual for calibration instructions Purity paramagnetic heater assembly Refer to figure 6 14 Removal a Remove purity paramagnetic gas sensor module see section 6 25 b Remove oven insulation 30 and two off 3 in one piece c Disconnect gas sensor signal cable 36 from PL1 on 01166 901 PCB 13 d
16. Remove four fixing screws 9 for the transducer bracket and remove transducer bracket complete with paramagnetic transducer and associated boards 13 15 Withdraw sample tubing through grommet 25 as transducer bracket is removed e Remove four heater plate fixing screws 18 and withdraw heater plate a sufficient distance to allow gas sensor module power cable to be disconnected from the temperature control board 04100 901 Refitting Use reverse procedure When refitting gas sensor module power cable to temperature control board ensure that centre core of power cable goes to 04100 901 terminal block TB1 terminal 3 The other two cores of the gas sensor power cable are located one each in terminals 2 and 4 Refer to the QuickStart manual for calibration instructions Purity paramagnetic transducer Refer to figure 6 14 Note The 01156A 000 paramagnetic transducer includes the 01156 904 PCB The temperature compensation is specific to this combination therefore the PCB supplied with the 01156A 000 must remain paired with it CAUTION The paramagnetic transducer and its cell should not be subjected to mechanical shock which may result in damage to the cell suspension Removal a Remove paramagnetic gas sensor module see section 6 25 b Remove oven insulation 30 and two off 3 in one piece c Remove sample connections 4 5 from paramagnetic cell 8 d Disconnect ribbon cable 35 from PL1 on 01156 904 PCB 15 e Dis
17. boards and the associated terminal boards via the instrument motherboard connectors Replace the mother board PCB if this is faulty and re validate instrument performance Replace the motherboard PCB and re validate instrument performance Analogue output readings not present Symptoms Analogue output readings not working Measurements and Diagnosis a Check that the analogue output channel assignment are correctly configured and enabled within the instrument software Correct where necessary and re validate instrument performance Check that interconnecting wiring is correctly installed within the screw terminal block within the external two part connectors This is conveniently accomplished by removing the connector and checking operation at the connector pins Correct where necessary and re validate instrument performance Ensure that the signal interface board optional output boards and associated terminal boards are correctly located within their connectors on the mother board Correct where necessary and re validate instrument performance If more than one output board is fitted and all outputs are not working then replace the microprocessor PCB and re validate instrument performance If the instrument has only one output board the Sensor Interface PCB or the fault lies within the first output board then replace the Sensor Interface PCB and or its associated terminal PCB and re validate instrument performance If th
18. figure 6 5b Removal Disconnect the external sample inlet and outlet connections to the instrument Remove the cover see section 6 1 Disconnect the electrical connectors 11 12 from the motherboard These leads are reversible and interchangeable Slide the hose clips on the inside of the inlet and outlet connectors 1 2 back up the sample tube by opening the spring clip with pliers Disconnect the sample tubing from the inlet and outlet connectors Refitting 1 2 Remove the four fixing screws 3 which hold the gland plates 4 5 to the casing 13 To lift the gland plate and PCB assembly clear of the casing raise it vertically until the lower part of the PCB 8 is able to clear the case when the assembly is rotated then lower it to clear the upper edge of the PCB Remove the nut and washer securing the earth strap from the PCB 8 to the functional grounding post 10 Remove the nuts 9 to release the PCB 8 from supporting studs in the gland plate 5 The spacers 6 are loose If necessary the gland plates 4 5 can be separated by removing the retaining nuts 7 from the inlet and outlet connectors 1 2 Use reverse procedure Figure 6 5b External autocalibration relay PCB 6 15 6 13 External fan Refer to figure 6 6 Figure 6 6 External fan Removal a Remove cover see section 6 1 b Remove power connector see section 6 11 C Disconnect fa
19. is low then perform the instrument measurement fault checks in section 5 4 4 If none of these checks rectify the problem then replace the transducer and verify performance 5 4 6 Flow faults 5 5 Symptoms Slow instrument response Drift Noise Flow sensitive results Measurement and Diagnosis a Verify that the sample flow rate through the transducer is in the range 100 250 ml min and is stable Verify that any flow stability problems encountered are not produced by any sample conditioning system used prior to sample entry into the instrument Particular attention should be made to knock out pots sample pumps chillers and filters Correct or replace where necessary and re verify instrument performance By performing a leak test verify that the internal pipe work within the instrument is leak tight Pay particular attention to flow meter leakages if these are fitted Correct or replace where necessary and re verify instrument performance Verify that the optional sample filter if fitted is clean and not blocked Correct or replace where necessary and re verify instrument performance Verify that the orifice flow restrictors within the instrument are not blocked Correct or replace where necessary and re verify instrument performance Verify that the pipe work attached to the instrument vent is not restrictive and resulting in pressurisation of the sample cell Correct or replace where necessary and re verify
20. list of the diagnostic signals available for the Pm O purity transducer assembly Table 5 3 Diagnostic signals for the Pm O purity transducer Diagnostic Description Typical Range level CELL EMF Cell output volts 0 1 V 0 1 to 1 2 V CELL TEMP Cell temperature 55 C 50 to 55 C CELL Cell sample pressure 15 psia 5 to 25 psia PRESSURE Paramagnetic cell output This is the raw output and is not pressure compensated or calibrated The signal is scaled approximately as follows OV corresponds to 0 oxygen and 1V corresponds to 100 oxygen A XXX fault is indicated if the raw cell output results in an A D conversion of zero or full scale this corresponds to a cell output of 0 25 V and 1 31V respectively Pm O purity cell temperature The oven which houses the paramagnetic cell runs at 55 C Errors in the indicated temperature mean that the displayed temperature will lie between 50 C and 55 C A XXX fault is indicated if the indicated cell temperature is above 70 C or below 50 C after 2 hours from switching on Pm O purity sample pressure The sample pressure is displayed in psia A fault is indicated if the sample pressure falls below 5 psia 35 kPaa or the resultant A D conversion is full scale this corresponds to approximately 26 2 psia 181 kPaa Fault messages Table 5 4 shows a list of the indicated fault condition for the Pm O purity transducer assembly 5 15 5 16 Table 5 4 Fault message
21. numbers for PL1 and the key to which they correspond With the instrument power switched off check that the correct resistance is seen across each set of pins when the corresponding key is pressed and not pressed Row c is the top row of pins and pin 1 is on the right when viewing the component side If the correct resistances are seen for all keys then the fault is probably located on the Microprocessor PCB If the correct resistances are not seen the fault may lie with the Keypad rubber mat the Keypad PCB or the ribbon cable Check continuity of keypad ribbon cable and replace if necessary 5 2 6 Table 5 2 Keypad pin connection details Key name matrix 02000 902 PL1 row c pin numbers MEASURE X3 Y4 25 22 MENU X3 Y3 EDIT X2 Y1 24 19 QUIT X3 Y1 ENTER X1 Y2 23 20 LEFT X3 Y2 RIGHT X1 Y1 23 19 UP X1 Y3 23 21 DOWN X1 Y4 23 22 Check whether the contact pills on the Keypad rubber mat or the corresponding gold flashed contacts on the Keypad PCB are contaminated Replace Keypad rubber mat or PCB as necessary or clean with a lint free cloth soaked in either MEK or acetone Do not soak the Keypad rubber mat or PCB in either of these solvents Do not touch the contact pills on the rubber mat or the gold flashed contacts on the keypad PCB by hand Output alarm relays do not operate Symptoms Alarm output relays do not operate Measurements and Diagnosis a Check that the relay assignment a
22. of causes are identified depending on whether the green LED on the processor PCB is on or not Mains power input short open circuit Measurements and diagnosis Disconnect the instrument from the mains power source Ensure that the analyser power switch is in the on position Check the resistance between Live and Neutral pins on the mains power supply cord The expected resistance depends on the mains voltage selection and should be within the following ranges 85V to 132 V setting lt 3 50 170V to 264V setting lt 140 The resistance seen is that of the transformer primary windings connected in either series or parallel The switched mode power supply will appear open circuit Check the resistance from Line to Earth and from Neutral to Earth using a suitable isolation tester These resistances should be greater than 1 MQ If the earth leakage resistance is less than 1 MQ determine where the fault lies by disconnecting the switched mode power supply transformer and mains cable form including IEC connector until the fault is rectified Check the fuse F2 on the rear panel of the chassis and replace it if necessary Check the fuse in the mains power cord and replace it if necessary Ensure that the mains voltage selector is set correctly and that the fuse is located in the correct side of the fuse holder see operators manual Repeat the mains power input resistance tests as necessary following any corrective actions If the input re
23. open Relay Contacts normally open PE a EE a ORBRODODN These identification numbers appear on the rear label to identify the terminals where each output appears and on the display when the outputs are being configured 1 7 Transducer full scale deflection The transducer full scale deflection FSD is the maximum concentration level that may be measured and displayed with the precision and accuracy specified for that transducer This may also be termed the measurement range for the transducer Concentration levels that exceed 120 of the FSD are considered as over range and are indicated by the word OVER on the analyser display which flashes alternating with the actual measured value of the gas concentration There are three set up parameters on the Xentra instrument that are expressed in terms of the FSD C Calibration tolerances for the transducers C Alarm hysteresis C The upper limit of the analogue output The maximum FSD values for the different transducer types that may be fitted inside the Xentra 4100 chassis are shown in table 1 1 Taner 50 7 Gfx 1210 N O Trace 0 vpm N O Gfx 1210 CH Trace 500 vpm CH 1 8 1 9 Displaying alarms present If the measurement display shows the ALARM icon the number and nature of the alarms present may be determined using the procedure described in Table 1 2 Table 1 2 Displaying alarms present L MENU to obtain top level menu CALIBRATE SETUP L
24. power switch It is fixed to the rear of the chassis by two screws 8 which have corresponding threaded inserts in the rear of the chassis An earth lead soldered onto the IEC power connector is connected to the earth stud 22 on the inside rear of the chassis This earth lead is kept as short as possible for EMC The IEC power connector is connected to the Motherboard via a four leads in an overall sleeve A four way connector 11 is used to make connections to the Motherboard Four individual insulated slide connectors are used to connect to the IEC power connector Transformer Refer to figure 6 4 The transformer 17 is fixed to the chassis from the underside using two screws with washers 15 16 These fix into threaded bushes potted into the centre of the toroidal transformer A rubber mat 23 is fitted to the underside of the transformer 2 5 21 10 2 1 11 21 12 2 6 External fan Refer to figure 6 6 The external fan 1 is fitted to the rear of the chassis along with a finger guard 3 and a fan mounting plate 2 using four screws 7 which fix into threaded inserts in the chassis The four screws pass through spacers 8 The fan mounting plate spreads the force of the fixing screws on the fan and helps prevent the fan filter element 4 fan filter gauze 5 and fan filter cover 6 from being dislodged These components would otherwise protrude as they are slightly larger than the fan itself The fan is connected to
25. replace where necessary and verify instrument performance Verify the power supply 5V rail voltage on the multiplexer PCB TPO5 wrt TPO1 5 05V 0 25V If the supply voltage is low or is not present then disconnect the following units in order to determine whether the 5V rail is being pulled down or the switched mode PSU is faulty Ensure that the instrument is switched off before connecting or disconnecting PCB assemblies Gas sensor modules Option boards Sensor interface boards Keypad ribbon cable Microprocessor board Multiplexer board by elimination of other possible causes Correct or replace where necessary and verify instrument performance Check the following output voltages on connector PL1 on the transducer house keeping PCB Pin 12 Cell temperature Pin 10 Cell output EMF Verify that these signals reflect the input gas composition when nitrogen and air gas samples are applied to the inlet port If the output voltages are incorrect then replace the transducer and re verify the transducer performance 5 17 Verify that the instrument diagnostic display for the transducer output EMF and temperature conform with those measured on pins 10 and 12 on connector PL1 on the transducer house keeping PCB If these are incorrect then the fault may lie within either the Multiplexer PCB or the Signal Interface PCB Correct or replace where necessary and verify instrument performance If none of the above tests have i
26. the Motherboard 9 The direction of flow is marked on the fan this is directed into the chassis Optional Internal Fan Refer to figure 6 7 The internal fan 2 is used where the gas sensor modules have a high power dissipation It is connected to the Motherboard 7 using connector 6 The internal fan is fixed to the front card frame 8 using four screws with nuts and washers 4 3 5 A fan mounting plate 1 is used to space the fan of off the front card frame so that the fan rotor does not touch the card frame Sample System Options The 4100 is offered with a choice of two sampling systems flow driven and pressure driven These sampling systems are transducer module dependent and a multi measurement analyser could contain a mixture of both The specific analyser configuration can be accessed via the user interface where the feature and options for the build are stored For a full list of the features and options refer to the 4100 Gas Purity Analyser Technical Data Sheet available from your local Servomex Company agent or representative Flow Driven Option Refer to Figure 2 1 The flow driven option is supplied for applications where the sample flow is to be controlled by the customer prior to entry into the analyser Minimum and maximum flows are transducer module dependent For more detail on transducer module specific flowrates please refer to the QuickStart manual Pressure Driven Option Refer to Figure 2 2 The pres
27. the concentration in the calibration gas autocalibration concentration configuration are outside of limits The results of an See section 5 6 4 autocalibration differ from the existing values by more than the tolerance limits The Gfx 1210 transducer performs some basic checks of the functionality of the main circuits and in the case that a malfunction is identified a logic signal Gfx transducer faulty is sent to the Xentra unit in order to inform the user that the transducer is faulty A faulty Gfx signal will activate the Fault Icon on the Xentra screen and the corresponding measurement value field will read VOID Other faults identified within the Xentra chassis will activate the Fault Icon only The green LED D16 on the housekeeping PCB 01210903 indicates the status of the transducer This LED will be extinguished if a transducer fault is sensed Figure 5 2 shows possible fault causes that would result in the D16 green LED being extinguished 5 34 SYMPTOM checke CAUSES Fuse F2 Blown Power on PL3 connector missing Faulty Mux PCB Faulty cable connections D15 LED off Power LED D16 LED off Faulty transformer Short circuit on Housekeeping PCB 1210 Gfx OK Ea Breakage inside the Chopper Box D13 LED off Loose cuvete window Motor LED Resistance in rotating the motor Chopper Box connector not fully inserted Motor connector not fully inserted Faulty Housekeeping PCB F
28. the gas sensor modules associated electronics and sample system On the front of the chassis is a plastic moulded fascia 5 which is used to mount the display and keypad Mounted on the front of the chassis but projecting through the fascia are a sample filter and two Flowmeter which are optional The fascia is fixed to the chassis using 8 screws Figure 6 2 13 Optional Flowmeter s Refer to figure 6 2 The Flowmeter consists of a flow tube 9 10 supported between end blocks 7 8 38 39 The end block spigots accommodate o rings 11 12 which seal to the flow tubes Each flowmeter has a moulded plastic cover 4 5 which provides access to the flow tube 9 10 for cleaning When the Flowmeters are not fitted the cover is replaced by a blank The cover or blank is fixed by a screw 3 accessible from inside the chassis 42 Optional Sample Filter Internal See 2 1 16 for external sample filter Refer to figure 6 2 The sample filter housing 26 has a clear polycarbonate cover 32 which may be unscrewed with the aid of the spanner provided with the Xentra to gain access to the filter element 83 The filter cover 32 is sealed to the filter housing using an o ring 34 When the sample filter is not fitted a blank is fitted to the fascia 29 Keypad Refer to figure 6 2 The keypad consists of a PCB 21 and a silicone rubber overlay 22 The rubber overlay has nine keys moulded into it each has a rubber contact pill which m
29. the measurement display are shown in figure 1 2 FRONT VIEW FLOWMETER SAMPLE FILTER DISPLAY VIEWING RACK MOUNTING BRACKETS ANGLE ADJUST REAR VIEW MAINS CONNECTOR SAMPLE INLET S FAN FILTER EMC GROUND SAMPLE OUTLET S FUNCTIONAL GROUND SERIAL OUTPUT PORT SIDE VIEW IDENTIFICATION LABEL SERIAL NUMBER LABEL Figure 1 1 Key features of the Xentra 1 6 Titles naal Process Variables see Message Icons Figure 1 2 Xentra measurement display Each measured value on the display is known as a process variable and consists of four fields as shown in figure 1 3 No A module location field 2 characters Value A measurement value field 6 characters Unit An engineering units field 3 characters Component A user defined message UDM field 6 characters Measurement value field 6 chars Engineering units field 3 chars User defined message field 6 chars 12 6 vpm Oxygen Figure 1 3 Xentra process variable format n pag To c O N Naa D Naga c 2 5 w O 2 o 5 o o pg The module location field defines which transducer the process variable represents The letter T indicates an internal gas sensor module the letter E indicates an external gas transducer user supplied The letter is followed by a number defining the gas sensor module site number The measurement field is a 6 character number represe
30. where necessary and re verify performance 5 4 5 Stability faults 5 26 Symptoms Noisy reading Reading drifts Instrument requires frequent re calibration Measurements and Diagnosis a Verify that the sample flow rate through the transducer is in the range 100 250 ml min and is stable Correct or replace where necessary and re verify instrument performance Perform a leak test to verify that the internal pipe work is free from leaks Correct or replace where necessary and re verify instrument performance Verify that the sample filter if fitted is not blocked and that there are no obstructions within the instrument vent line Correct or replace where necessary and re verify instrument performance Verify that the instrument is free from condensed water Correct or replace where necessary and re verify instrument performance Verify continuity of interconnecting wiring from the transducer cell to the transducer house keeping PCB and from the transducer to the MULTIPLEXER PCB Correct or replace where necessary and re verify instrument performance Unplug the transducer from the MULTIPLEXER PCB and verify that the instrument is now stable If not then the fault is likely to lie with the Sensor Interface PCB or MULTIPLEXER PCB Identify and replace faulty PCB s where necessary and re verify instrument performance Check instrument sensitivity by performing a zero and span calibration If the instrument sensitivity
31. with changing gas composition Transducer producing invalid results Measurements and Diagnosis a Verify continuity of interconnecting wiring between the measurement cell and the house keeping PCB and between the transducer and the Multiplexer PCB Correct or replace where necessary and verify instrument performance Verify the power supply 5V rail voltage on the multiplexer PCB 5 23 5 24 TPO5 wrt TPO1 5 05V 0 25V If the supply voltage is low or is not present then disconnect the following units in order to determine whether the 5V rail is being pulled down or the switched mode PSU is faulty Ensure that the instrument is switched off before connecting or disconnecting PCB assemblies Gas sensor modules Option boards Sensor interface boards Keypad ribbon cable Microprocessor board Multiplexer board by elimination of other possible causes Correct or replace where necessary and verify instrument performance Check the following output voltages on connector PL1 on the transducer house keeping PCB Pin 12 Cell temperature Pin 10 Cell output EMF Verify that these signals reflect the input gas composition when nitrogen and air gas samples are applied to the inlet port If the output voltages are incorrect then replace the transducer and re verify the transducer performance Verify that the instrument diagnostic display for the transducer output EMF and temperature conform with those measured on pins
32. 000 adjust RV2 until the displayed temperature is 725 1 C For zirconia sensor 00704000 adjust RV2 until the displayed temperature is 575 1 C Note Gases referred to below should be introduced to the module via the sample inlet connector at 5psig 3psig for pressure driven systems or 200 to 550 ml min for flow driven systems Introduce clean dry instrument air Monitor the voltage at TP2 with respect to TP3 once the reading has stabilised adjust RV3 to obtain a reading of 106 0 1mV If available introduce a nominal 0 3 oxygen in nitrogen gas mixture Check that the reading TP2 wrt TP3 is as specified by the following formula Nominal Reading 106 2 3 x 2 1543 x 10 x 848 x In 20 95 P1 mV Where P1 is the actual percentage oxygen concentration of the nominal 0 3 oxygen in nitrogen gas mixture Permitted tolerance 1mV 10mV If the reading is greater than the maximum permitted value re adjust RV1 temperature to give the nominal reading 1 mV If the reading is below the minimum permitted value re adjust RV1 temperature to give a reading between 8 and 10mV below the nominal reading Calibrate the zirconia gas sensor module Refer to QuickStart manual 6 24 Zirconia cell Refer to figure 6 10 WARNING The surface of some components within the zirconia gas sensor module assembly are hot Switch off the electrical power and allow 10 minutes for the zirconia cell to cool before servicing module
33. 0700 102 Zirconia transducer housekeeping circuit A2 2 diagram 8 4 NOTES
34. 2 1 Removal of flow connector a Slacken the two nuts 2 on the connector 1 b Carefully pull out the sample pipework and remove the connector 1 C Slacken off the connector at the rear of the chassis amp remove the sample inlet pipe Refitting a Use reverse procedure 6 25 6 23 Zirconia control board Removal Refer to figure 6 13 Note on newer zirconia sensors wire colours will be Ss c06 0010 O an QO Fixe ILK10 x2 Pins Kef gh a TP2 LK i o juke Ka i rv3P_ LK5 RV2 CE Wi O O SSSV kas O Figure 6 13 Zirconia control board WARNING Pin 1 yellow Pin 2 blue Pin 4 green Pin 5 white Pin 9 red Pin10 red The surface of some components within the zirconia gas sensor module assembly are hot Switch off the electrical power and allow 10 minutes for the zirconia cell to cool before servicing module Remove zirconia gas sensor module see section 6 20 control module PCB 3 b Disconnect wiring from the terminal block TB1 on 00700 902 zirconia c Undo four off fixings for Zirconia control module PCB 10 by rotating 1 4 turn anti clockwise d Lift zirconia control module PCB from four fixings 10 Refitting Use reverse procedure Connections from the zirconia cell to terminal block TB1 6 26 on the 00700 902 zirconia control board are shown in figure 6 13 Set links as per the original board se
35. 2 and D3 on the Microprocessor PCB are initially illuminated after power up and are then extinguished after approximately 5 seconds If LED s are not extinguished then replace the microprocessor PCB Note Replacing the microprocessor PCB will require reconfiguration of the analyser Refer to section 7 2 5 7 5 2 4 5 2 5 5 8 Keypad ribbon cable faulty Measurements and diagnosis Check the continuity of keypad ribbon cable Replace the ribbon cable if necessary System failure bad exec message Re start the analyser by switching the power off momentarily If the fault persists then replace the Microprocessor PCB Note Replacing the microprocessor PCB will require reconfiguration of the analyser Refer to section 7 2 Incorrect or no response to key presses The Microprocessor has a matrix of digital inputs 4 off X inputs and 3 off Y inputs each key is connected across one X input and one Y input See Keypad PCB circuit diagram 04000 103 The Microprocessor board scans the inputs to determine which key is pressed Measurements and diagnosis Check continuity between keypad switches and microprocessor board Switch off power and remove option cards 3 and 4 figure 6 4 4 5 to allow access to PL1 on the microprocessor board this is the plug which connects to the Mother board A pressed key should give a resistance of less than 100Q an unpressed key should give a resistance of greater than 10KQ Table 5 2 gives the pin
36. 3 LIST OF FIGURES Figure Page 5 1 Display not illuminated fault tree 20 0 0 cee ees 5 4 5 2 Gfx fault icon on diagnosis tree og 52 tees sie oe ei tiie ws ieee wie ee we 5 35 5 1 5 2 NOTES 5 1 5 2 5 2 1 FAULT FINDING Introduction This section is categorised according to the component on which the fault is observed and the possible observed symptoms Under each Symptom heading are listed faults which would cause the symptoms For each of the faults listed there are some checks to determine the nature of the fault The fault symptoms listed are categorised into groups relating to either the core instrument chassis assembly or the individual transducers to which they apply Information regarding faults on the different instrument components are to be found in the following sections 5 2 Xentra 4000 chassis 5 3 Paramagnetic O Purity transducer 5 4 Paramagnetic O Control transducer 5 5 Zirconia transducer 5 6 Gfx 1210 transducer Diagnostic readings available through the user interface give raw readings from transducer modules This provides valuable information for fault finding Instructions on displaying this information are given in section 1 11 The instrument software also maintains a history log of the previous 40 faults and calibrations Instructions for displaying this information are given in sections 1 9 and 1 10 Xentra chassis faults This section of the manual covers likely fault symp
37. 4VDC supply for the solenoid valves is sourced on the Multiplexer PCB With the solenoid valves unplugged then check that the 24VDC rail is available on TP0O8 wrt TPO1 on the multiplexer PCB If the rail voltage is present then replace the multiplexer PCB and re validate the instrument performance Replace the sensor interface PCB and re validate the instrument performance Replace the microprocessor PCB and re validate performance Note Replacing the microprocessor PCB will require reconfiguration of the analyser Refer to section 7 2 Replace the motherboard PCB and re validate performance 5 2 13 Overheating 5 14 Symptoms Internal temperature of instrument is too high Measurements and Diagnosis a b c d Check that the ambient operating temperature does not exceed 40 C Check that the external fan filters are clean and the cooling fan operates Replace where necessary and re validate instrument performance If an internal cooling fan is provided then check that this is operational Check that the ventilation holes are not obstructed Check that the internal transducers are operating at their correct temperatures and are not overheating 5 3 5 3 1 5 3 2 Paramagnetic O purity transducer faults This section of the manual covers likely fault symptoms associated with the Pm O purity transducer assembly The faults are categorised by the observed symptoms Diagnostic measurements Table 5 3 shows a
38. 50 ml min and is stable Correct or replace where necessary and re verify instrument performance b Perform a leak test to verify that the internal pipe work is free from leaks Correct or replace where necessary and re verify instrument performance CAUTION The paramagnetic transducer should not be pressurised above 10 psig 70 kPag When leak testing the pipework care should be taken that the paramagnetic cell is pressurised and depressurised slowly Failure to do this may result in damage to the cell C Verify that the sample filter if fitted is not blocked and that there are no obstructions within the instrument vent line Correct or replace where necessary and re verify instrument performance d Verify that the instrument is free from condensed water Correct or 5 19 5 3 6 5 20 replace where necessary and re verify instrument performance e Verify continuity of interconnecting wiring from the transducer cell to the transducer house keeping PCB and from the transducer to the MULTIPLEXER PCB Correct or replace where necessary and re verify instrument performance f Unplug the transducer from the MULTIPLEXER PCB and verify that the instrument is now stable If not then the fault is likely to lie with the Sensor Interface PCB or MULTIPLEXER PCB Identify and replace faulty PCB s where necessary and re verify instrument performance g Check instrument sensitivity by performing a zero and span calibration I
39. 980 KIT FRONT FASCIA ASSY Figure 6 2 29 Includes Window and gasket already installed flowmeter covers and blanks labels and sample filter blank with adhesive Figure 6 2 9 10 Includes o rings S4000982 50 500mL FLOWMETER Figure 6 2 9 10 Includes o rings 54000983 KIT FAN REPLACEMENT Use for external Figure 6 6 1 o internal fan Figure 6 7 2 4000984 RACK MOUNT KIT SHORT CHASSIS See operators manual 4000985 RACK MOUNT KIT LONG CHASSIS See operators manual 4 4 54000986 KIT SOCKET 14W SIGNAL See operators manual 54000987 KIT FINE FILTER CAP Figure 6 2 32 Includes o ring S4000988 KIT FILTER ELEMENTS 6p Figure 6 2 33 54000990 0 5 2 5L FLOWMETER Figure 6 2 9 10 Includes o rings 4100902 PARAMAGNETIC MODULE HEATER Figure 6 14 19 PLATE 4100924 RESTRICTIVE T ASSEMBLY ZR Figure 6 11 1 4100925 RESTRICTIVE T ASSEMBLY GFX Figure 6 22 4 4100993 ZIRCONIA GAS SENSOR MODULE Figure 6 10 703 CELL 4100994 ZIRCONIA GAS SENSOR MODULE Figure 6 10 704 CELL 4100995 PURITY PARAMAGNETIC SENSOR Figure 6 14 MODULE TEMP CONTROLLED WITH PRESSURE SENSOR 4100996 CONTROL PARAMAGNETIC GAS Figure 6 15 SENSOR MODULE 00700922 INLET PIPE ASSY ZIRCONIA CELL Figure 6 10 4 04000934B RIBBON CABLE ASSY 550MM 04000937D 1156 RIBBON CABLE 750MM CE VU 04100002B 4100 SERVICE MANUAL oaioo00s8 cucxstanTuawaens OSSSSC S 04100013B QUICK
40. C5 to four averaging circuits comprising IC6 C24 C25 C26 and C27 These averaged signals are DNIT dark nitrogen LNIT light nitrogen DGAS dark gas and LGAS light gas which are differentially processed to remove the common mode dark signals from LNIT and LGAS Low pass filtering and gain adjustment is provided by two sections of IC8 and the outputs are Vitogen ANA V as CS and C3 provide EMC protection and these signals are sent to the MAST connector The remaining section of IC8 produces a difference signal from Vyitogen ANG Vyas named Van and this signal is sent to the MAST connector through low pass filter LC7 IC5 is a DPG508A analogue multiplexer and IC6 is a AD704 quad op amp connected to form two difference amplifiers with high impedance inputs IC5 samples the light and dark signals for CO and nitrogen while the difference amplifiers subtract the dark signals from the light signals to provide the Vas and V nitrogen Signals R3 C4 and IC8 pin 5 6 and 7 provide low pass filtering for the output V itrogen R4 C2 and IC8 pin 1 2 and 3 provide low pass filtering and a variable gain buffer SW1 and RV1 provide coarse and fine gain adjustment for transducer calibration The output V as is calibrated to be equal with V when the sample gas does not contain any CO nitrogen RN4 and IC8 pin 12 13 and 14 provide a variable gain difference amplifier The value of R14 430 ohms was selected in order to provide a 1
41. ENTER ALARMS FAULTS DISPLAY ALARMS L ENTER ALARM HISTORY l2 Oxygen AL1 The first alarm is displayed if further alarms are 99 98 Yo HIGH 8 present an arrow will be shown L gt or to access information on further alarms NASA alarms have POEN viewed L MEASURE Displaying faults present If the measurement display shows the FAULT icon the number and nature of the faults present may be determined using the procedure described in Table 1 3 Table 1 3 Displaying faults present L MENU to obtain top level menu CALIBRATE SETUP L lt ENTER ALARMS FAULTS DISPLAY FAULTS L ENTER FAULT HISTORY 11 CELL TEMP The first fault is displayed if further faults are LOW 8 present an arrow will be shown L gt or to access information on further faults When faults have been viewed L MEASURE to 1 10 Displaying alarm history An entry is made in the alarm history buffer each time an alarm appears or is cleared The alarm history buffer contains the most recent 40 events Note that if hysteresis has been specified when configuring an alarm then the alarm will not clear until the concentration has reached the alarm level plus the hysteresis Table 1 4 describes the procedure for displaying the alarm history Table 1 4 Displaying alarm history L MENU to obtain top level menu CALIBRATE SETUP L ENTER ALARMS FAULTS DISPLAY ALARMS L ENTER ALARM HISTORY I2 Oxygen AL2 ON L gt or to view further entries 12 13 20 12 06 8 L MEAS
42. O A o A Q o o O o N Terminal Board o PL1 04000904 suonosuuog jeujaxg mA Relay Board option A 02000906A Terminal 02000902A Board o PL2 04000904 Keypad PCB Terminal 04000932 04000903 Board o PL3 04000904 option C Terminal 02000906A Board o PL4 04000904 suonoeuuog jeusa xg jeuondo o PL6 Not Used Options shown dotted Figure 2 6 Electronic system block diagram 2 14 2 2 2 Switched mode power supply Refer to figure 6 4 The switched mode power supply 19 operates between 85 to 264V and is not affected by mains voltage selection It provides 15V 15V 5V and 24V isolated supplies The isolated 24V positive supply is grounded on the Motherboard to generate 24V for the display viewing angle adjustment A short circuit or overload on the 24V rail will shut down all of the outputs These will run at approximately 0 5V as the power supply tries to restart A short circuit or overload on the 5V 15V or 15V rails will not affect the other rails Display lamp drive The display lamp runs at approximately 300V ac 4 KHz the voltage required to strike the lamp initially is 1 5KV The lamp is driven from an invertor mounted on the keypad PCB which uses the 24V supply Signal processing Standard gas sensor module connector The Gas sensor modules and Multiplexer board are connected via a 20 way ribbon cable All Gas sensor modules have a common pin out This means that Gas sensor mod
43. PL1 is different in respect with the reference of 2 5 volts When the power is switched on the resistance of the thermistor is high and in consequence the voltage on pin 18 PL1 will be lower then 2 5 volts A 3 9 3 10 current will flow through R8 which will charge C4 and the integrator output voltage will increase This will have as an effect an increase in power applied to the chopper box heaters Once that the thermistor will see a temperature closed of 65 C the voltage on pin 18 PL1 will become approximately zero the integrator output voltage will not increase any more and the power applied to the heaters will remain constant Any change in the thermistor s resistance will the change the power applied to the heaters in order to keep the chopper box temperature constant Transistor TR1 limits the integrator output range and results in faster temperature stabilisation by preventing unnecessary voltage swing after the output transistor is saturated The two sections of IC2 are unity gain buffers for the AD590 temperature sensors on the IR detector pre amp and chopper box The ICs 4 5 6 and 7 form a standard configuration for hall effect commutated brush less motors Passive low pass filters have been added to the Hall inputs to prevent EMC inducing spurious commutation IC6 is the motor driver IC and IC7 is the phase locked loop motor speed controller Speed errors are detected and signalled by IC7 IC4 TR4 and IC13 use this error sig
44. R sensor figure 3 2 6 responds to changes in infra red radiation levels falling upon its sensing area An output signal appears on pin 2 of IC3 which connects to R3 IC3 load resistor and a passive high pass filter formed by C3 and R4 C4 provides low pass filtering The resulting signal is then amplified by part of IC1 a variable gain amplifier The gain of this stage can be set between 28 and 128 by adjusting RV1 The amplified signal then passes to the second part of IC1 which is a precision differentiator circuit Output current is limited by R9 and C13 is for EMC protection A stabilized supply for the P I R detector is provided by using the Zener diode D1 in a resistive divider circuit C1 and C2 provide further filtering of the power supply for the P I R detector The Signal Processing PCB 01210902 Refer to circuit diagram 01210 103 On the Signal Processing PCB the signal from the pre amp PCB is sequentially distributed to four sample and hold circuits The averaged dark signal is subtracted from the averaged signals corresponding to nitrogen and CO The resulting nitrogen signal is subtracted from the CO signal and is provided together with the CO signal to the Xentra unit in order to work out the CO concentration The signal from the pre amp board passes through a low pass filter LC2 and through R2 to IC5 pin 8 and one section of IC8 which is a unity gain buffer for TP1 This signal is sequentially distributed by I
45. START MANUAL FRENCH 04100023B QUICKSTART MANUAL GERMAN cel 04100408 PIPE P D BYPASS OUTLET 04100431 PIPE ZR MODULE 1 INLET See section 6 21 04100432 PIPE ZR MODULE 2 INLET See section 6 21 04100433 PIPE ZR MODULE 3 INLET See section 6 21 04100434 PIPE ZR MODULE 4 INLET See section 6 21 04100435 INLET TUBE GFX MODULE 1 See section 6 42 4 5 04100436 INLET TUBE GFX MODULE 3 See section 6 42 04100437 OUTLET TUBE GFX Figure 6 3 1 or Figure 6 2 31 2344 0027 COUPLING 1 8 OD F SS SWA 2377 3831 EXTERNAL STAINLESS STEEL See section 2 2 16 FILTER UNIT COMPLETE 2360 1678 RESTRICTOR 0 25mm BROWN 2383 1638 RESTRICTOR 0 010mm CREAM 2388 1981 FILTER ELEMENT FAN Figure 6 6 4 2527 3041 MODULE POWER CABLE 7 WAY 3912 8010 KEYMAT MOULDING Figure 6 2 22 4911 6034 SWITCHED MODE POWER SUPPLY Figure 6 4 19 4961 1159 TRANSFORMER 4 TX Figure 6 4 17 Includes rubber mat 4961 1166 TRANSFORMER 2 TX Figure 6 4 17 Includes rubber ma SECTION 5 FAULT FINDING LIST OF CONTENTS Section Page Beds ntrod cli m aa see cee eerie KAT NA DRE Ea SO OE DEO Tea OS 5 3 5 2 Xentra Chassis Faults 2 0000 ee 5 3 5 3 Paramagpnetic O Purity Transducer Faults 5 15 5 4 Paramagpnetic O Control Transducer Faults 5 22 5 5 Zirconia Transducer Faults cece eee 5 28 5 6 1210 Gfx Transducer Faults 0c eee eee 5 3
46. The editor can be used to display the data by stepping through it with the ENTER key Providing nothing is changed re calculation of the linearisation function will not take place EDIT TC It is also possible to edit the coefficients of the temperature compensation function for the Gfx bench There are four such coefficients which provide a linear and a square term correction for sample temperature to both the zero offset and span The editor can be used to display the data by stepping through it with the ENTER key 7 9 7 4 710 Recording the Base Offset of External Inputs The purpose of super calibrating external inputs is to remove any baseline offset due to tolerances in the input circuitry This need only be done if the 04000 924 board or the EEPROM on the microprocessor board figure 7 1 8 is replaced Before recording the base offset it is necessary to disconnect any external inputs from PL5 1 2 3 4 which should be left floating The corresponding digital status inputs PL5 9 10 and 7 8 must be shorted out to ensure that the input channels are being read Select which of the channels is to be calibrated from the super calibration list The screen will show El BASE OFFSET 167760 OK Y N The number on the display is simply the digitised reading from a floating input and should lie in the range 146 000 189 000 If this is not the case and nothing is connected to the input terminals the 04000 924 board is faulty
47. UA NAAT eke 1 5 1 2 Xentra measurement display eee ees 1 6 1 3 Xentra process variable format 00 ee 1 6 dd The Xentrake pada Baa LARA eee et eee eee eee Cee GAGA GG 1 8 LO Xentrastat s ICONS 7a papa A A BANAT UNAN UB ANAN NG 1 9 1 6 User interface menu map 2782s sees NGA an oad AO gd ANG a eed dees 1 11 1 1 1 2 INTRODUCTION Introduction This manual contains essential information regarding servicing of the Servomex Xentra 4102 and 4104 Gas Purity Analysers This service manual is intended for use by Servomex trained service personnel The manual contains technical descriptions fault diagnosis information part removal refitting and test instructions as well as electrical and mechanical drawings and illustrations Repairs to PCB s are effected by board replacement Component replacement is not recommended The only exception to this is the display lamp Invertor mounted on the keypad WARNING The user should note that the Xentra 4100 instrument contains no user serviceable parts inside The instrument enclosure protects the user from electric shock and other hazards All servicing should be referred to qualified service personnel General description The Servomex Xentra chassis is a platform into which gas sensor modules may be fitted to make precise measurements Up to four modular gas sensors for a wide range of gases and concentration levels selected according to the customer s needs re
48. URE to return to measurement display Displaying fault history An entry is made in the fault history buffer each time a fault appears or is cleared The fault history file contains the most recent 40 occasions where a fault appeared or was cleared Table 1 5 describes the procedure for displaying the fault history Table 1 5 Displaying fault history L MENU to obtain top level menu CALIBRATE SETUP L lt ENTER ALARMS EAULTS DISPLAY FAULTS L ENTER FAULT HISTORY I1 CELL T LOW ON L gt or to view further entries 12 13 20 12 06 8 L MEASURE to return to measurement display 1 12 Displaying calibration history An entry is made in the calibration history buffer each time a calibration or calibration check is performed The calibration history file contains the most recent 40 occasions when a calibration or check was performed The following data is recorded for each occasion The information is displayed in the following format gas sensor module site number measurement name type of calibration difference time and date e g The display for a manual low calibration of the Oxygen sensor in site 3 with a correction of 0 213 at 14 54 on 24 July would be I3 Oxygen CML 0 213 14 54 20 24 07 Calibration types CorV Calibration or calibration check Validate Mor A Manual or Auto LorH Low or High MPO Measure Pressure transducer Offset SPO Specify Pressure transducer Offset Difference Difference betwee
49. W fault reported CELL EMF HIGH fault reported No response from transducer with changing gas composition Oxygen reading low Transducer producing invalid results Measurements and Diagnosis 5 29 5 30 NOTE A low or zero oxygen reading is a normal instrument response to the presence of combustibles components in the sample gas stream and may not be an instrument fault The reduction in the oxygen reading reported is dependant on the combustibles level present and cell type If there is sufficient combustibles in the sample gas to consume all of the oxygen present resulting in reducing conditions at the cell electrode then gen reading Verify continuity of interconnecting wiring between the zirconia measurement cell and the house keeping PCB and the two connections 20 way and 7 way between the transducer and the Multiplexer PCB Correct or replace where necessary and verify instrument performance Verify the 15VAC rail voltage supplies to the transducer house keeping PCB These supplies are provided on the 7 way connector PL1 Pin 5 15V AC Pin 6 OV AC Pin 7 15V AC If the voltages are incorrect then check the appropriate fuses F1 to F8 on the multiplexer PCB Correct or replace where necessary and verify instrument performance Verify that the instrument diagnostic display for the transducer output and temperature conform with the signals measured on connector PL2 on the transducer house keeping PCB P
50. When ENTERed the value is stored and used as a zero offset in subsequent scaling calculations SECTION 8 ENGINEERING DRAWINGS Section 8 Engineering Drawings LIST OF CONTENTS 8 1 8 2 NOTES 8 ENGINEERING DRAWINGS The following electronic circuit drawings are attached as part of this service manual Drawing No Description Size No Sheets Instrument Chassis 02000 102 Microprocessor PCB circuit diagram 02000 106A Dual mA Dual relay PCB circuit diagram A3 02000 124 Sensor interface PCB circuit diagram 04000 101 Motherboard PCB circuit diagram A1 04000 103 04000 104 04000 107 04000 124 Multiplexer PCB circuit diagram Paramagnetic Modules 01156 103 Paramagnetic house keeping PCB 01156 104 Paramagnetic transducer terminal PCB 01166101 Paramagnetic transducer pressure A3 1 transducer PCB circuit diagram 04100101 Oven temperature control PCB circuit A3 1 diagram Gfx Modules 01210 101 I R Detector pre amplifier circuit diagram A4 1 01210 701 CO transducer only 01210 101A I R Detector pre amplifier circuit diagram A4 1 01210 731 CO 01210 741 N O and 01210 751 CH transducers Keypad PCB circuit diagram Terminal output PCB circuit diagram Autocal relay PCB circuit diagram 01210 102 Signal processing PCB circuit diagram A3 1 01210 103 Housekeeping PCB circuit diagram 01210 104 1210 motor PCB circuit diagram zirconia Modules 0
51. Xentra 4100 Gas Purity Analyser Service Manual Ref 04100 002B 2 Order as part 04100002B NOTES HAZARD WARNINGS LETHAL VOLTAGES THE ELECTRICAL POWER USED IN THIS EQUIPMENT IS AT A VOLTAGE HIGH ENOUGH TO ENDANGER LIFE BEFORE CARRYING OUT SERVICING OR REPAIR THE EQUIPMENT MUST BE DISCONNECTED FROM THE ELECTRICAL SUPPLY TESTS MUST BE MADE TO ENSURE THAT DISCONNECTION IS COMPLETE IF FOR ANY REASON THE POWER SUPPLY CANNOT BE DISCONNECTED FUNCTIONAL TESTING MAINTENANCE AND REPAIR OF THE ELECTRICAL UNITS IS ONLY TO BE UNDERTAKEN AS A LAST RESORT AND MUST BE CARRIED OUT BY PERSONS FULLY AWARE OF THE DANGER INVOLVED WARNINGS CAUTIONS AND NOTES This publication includes WARNINGS CAUTIONS AND NOTES which provide where appropriate information relating to the following WARNINGS Hazards which will result in personal injury or death CAUTIONS Hazards which will result in equipment or property damage NOTES Alert the user to pertinent facts and conditions NOTICE This service manual for the 4100 Gas Purity Analyser covers disassembly procedures for this equipment and brief technical descriptions of component parts of the equipment It should be thoroughly read and retained by the service engineer NOTES CONTENTS Section 1 Introduction Read this section before commencing any work on the analyser 2 Product Overview Provides a mechanical and electronic overview These should be read to provide orienta
52. ables and leads from the PCB Unlock the six PCB fixings 9 and ease the PCB upwards Slide it away from the chopper box raising the cell assembly if necessary until free of the transducer SLO Refitting a Reassemble as above in the reverse order CAUTION Ensure that the correct cables are fitted to the correct sockets before applying power see figure 6 20 b Replace the transducer into the 4100 chassis in the same position see section 6 30 c Setup transducer according to section 6 41 d If a new house keeping PCB has been installed then the calibration data for the transducer must be transferred from the 4100 microprocessor PCB to the transducer Switch on the 4100 enter the SUPERCAL menu see section 7 and perform a transducer data UPLOAD to copy the calibration data onto the on board EEPROM e Calibrate according to section 6 41 6 47 6 40 Gfx signal processing PCB assembly 6 48 Removal Refer to figure 6 16 Remove the transducer from the 4100 chassis see section 6 30 Remove the cell assembly see section 6 32 Remove the two cell anti vibration fixings and mounts 12 Remove all connecting cables and leads from the house keeping PCB Unlock the six house keeping PCB fixings 9 and ease the PCB upwards Slide the PCB away from the chopper box raising the cell assembly if necessary until free of the transducer Release the cables from the transducer chassis 6 Refer to figure 6 17
53. ad range of operating temperatures The output signal conditioning circuits provide temperature compensation and incorporates coarse and fine span adjustment and fine zero adjustment The output signal is provided at PL1 Pin 10 wrt Pin 9 The voltage reference generates reference voltages of both positive and negative polarity These signals are used with the fine zero adjustment and the temperature output circuits They also provide an offset to the zero temperature compensation circuitry thus ensuring the compensation signal level at the calibration temperature is zero The zero temperature compensation is derived from the thermometer output The level of compensation is factory set The kick circuit is only functional during power up If the sample gas is pure oxygen and the power to the transducer is lost some units will deflect to a point where the reflected light beam does not fall onto the photocells When power is restored the kick circuit supplies an appropriate current in order to restore the feedback control The negative supply circuit generates the negative supply rail required by the remaining circuitry 3 5 3 2 Gfx 1210 transducer module 3 2 1 Principles of operation 3 6 The Gfx 01210 is a Servomex Infrared Gas Filter Correlation transducer 4100B versions measure carbon monoxide CO carbon dioxide CO nitrous oxide NO and methane CH over the standard ranges shown below TABLE 2 2 GFX MEASURAND
54. adiation Adequate clearance and or shielding must be provided to ensure that the Board s temperature ratings are not exceeded WARNING The cell temperature may reach approximately 1000C under certain fault conditions Installation must allow for this The Board contains sensitive circuitry that may be affected by RFI The design of enclosure and the method of mounting must provide the degree of protection necessary to meet the required EMC performance Configuration information is documented in the specification 3 15 3 16 NOTES SECTION 4 SPARES LIST Section 4 Spare List LIST OF CONTENTS 4 1 4 2 NOTES 4 SPARES LIST PART DESCRIPTION COMMENTS NUMBER S07000902 ZIRCONIA HOUSEKEEPING PCB Figure 6 10 11 S0703000 ZIRCONIA SENSOR Figure 6 10 6 S0704000 ZIRCONIA SENSOR LOW ACTIVITY Figure 6 10 6 1156A000 PARAMAGNETIC TRANSDUCER Figure 6 14 17 S1166901 PRESSURE TRANSMITTER PCB Figure 6 14 13 S1200923 SCRUBBER ASSEMBLY Figure 6 19 5 S1210501 KIT SCRUBBER SACHET Figure 6 17 34 S1210701 GFX TRANSDUCER CO See section 6 30 1210731 GFX TRANSDUCER CO See section 6 30 1210741 GFX TRANSDUCER N O See section 6 30 1210751 GFX TRANSDUCER CH See section 6 30 1210901 KIT DET PRE AMP ASSEMBLY See section 6 37 S1210902 KIT SIGNAL P C B See section 6 40 S1210903 KIT HOUSEKEEPING P C B See section 6 39 S1210904 KIT CHOPPER BOX ASSEMBLY See section
55. agram Refer to figure 3 1 A physical property which distinguishes oxygen from most other common gases is that it is paramagnetic This means that molecules of oxygen are weakly attracted into a magnetic field This paramagnetic behaviour is used within the 1156A transducer to measure the concentration of the oxygen Two glass spheres are fixed at both ends of a bar to form a dumb bell which is sealed 1 The gas under test surrounds the dumb bell within the sample cell 2 This dumb bell is suspended in a symmetrical non uniform magnetic field The dumb bell is slightly diamagnetic so that it takes up a position slightly away from the most intense part of the magnetic field When the surrounding gas contains oxygen then the oxygen molecules will be attracted into the strongest part of the magnetic field This pushes the dumb bell further out of the magnetic field due to the relatively stronger force on the paramagnetic oxygen The magnitude of the torque acting on the dumb bell will be proportional to the paramagnetism of the surrounding gases and hence proportional to the oxygen 3 3 3 4 concentration The 1156A paramagnetic transducer incorporates a strong rare metal taut band suspension mechanism onto which is mounted the dumb bell 1 The zero position of the dumb bell is sensed by a photocell assembly 4 which receives light from a mirror 2 attached to it The output from the photocell is amplified 3 and fed back to a coil woun
56. ak test to verify that the internal pipe work is free from leaks Correct or replace where necessary and re verify instrument performance C Verify that there are no obstructions within the instrument vent line Correct or replace where necessary and re verify instrument performance d Check instrument sensitivity by performing a zero and span calibration If the instrument sensitivity is low then perform the instrument measurement fault checks in section 5 5 3 e If none of these checks rectify the problem then replace the transducer and verify performance Flow faults Symptoms Slow instrument response Drift Noise Flow sensitive results Measurement and Diagnosis a Verify that the sample inlet pressure or flow is within the required range For pressure driven options this is 5psig 3psig 35kPag 21kPag For flow driven options this is 200 to 550 ml min Correct or replace where necessary and re verify instrument performance b By performing a leak test verify that the internal pipe work within the instrument is leak tight Pay particular attention to flow meter leakages if these are fitted Correct or replace where necessary and re verify instrument performance C Verify thatthe orifice flow restrictors within the instrument are not blocked Correct or replace where necessary and re verify instrument performance d Verify that the pipe work attached to the instrument vent is not restrictive and resulting in p
57. akes contact with the PCB when the key is pressed The fascia has 2 3 2 4 five locating pegs 28 which are used to locate the rubber overlay and keypad PCB The keypad is then fixed to the fascia using four screws 20 with the rubber overlay sandwiched between One of the keypad PCB fixing screws has a spacer 27 which prevents the screw breaking through the front of the fascia The invertor 41 which provides a high voltage for the cold cathode fluorescent lamp is mounted on the keypad PCB The potentiometer for adjustment of the display viewing angle is mounted on the keypad PCB 21 Fascia EMC components Refer to figure 6 2 The display window 43 is fixed into the fascia independently of the display The inner surface of the window is metallised this metallisation is connected to a conductive coating on the inner surface of the fascia by copper tape with conductive adhesive 30 A web wall on the inner surface of the fascia which goes around the display and keypad carries an EMC gasket 31 this is used to connect to the front of the chassis thus providing a complete conductive envelope around the keypad and display Display Refer to figure 6 2 The display is fixed to the fascia by four screws 23 it has no user serviceable parts Card frame Refer to figure 6 9 The card frame mounted at the rear of the chassis consists of a front card frame 10 and a rear card frame 7 Both card frames have snap in plastic c
58. al amplification conditioning circuits the thermometer signal conditioning circuits the span temperature compensation the output signal conditioning circuits a voltage reference the zero temperature compensation the kick circuit the negative supply generation OE Or Ou CO Not A short description of each circuit The constant current source provides a constant current for the infrared LED PL2 pins 1 and 3 The position of the test body dumbbell is detected by a pair of photocells connected in parallel opposition The photo cell assembly can be moved along the path in order to place them in an appropriate position for a null output This mechanism is termed the coarse mechanical zero The current output of the photocells which is proportional to the deviation of the test body from the null position is fed into the current amplifier At the output of the amplifier a phase advance network ensures the stability of the servo system The test body assembly includes the feedback coil on the test body thus completing the servo loop The thermometer signal conditioning circuits include an electronic thermometer placed in close contact with the face of the transducer The thermometer supplies a current which is proportional to the absolute temperature This signal is used for zero temperature compensation The span temperature compensation relies on a thermistor and a resistance network It provides temperature compensation over a bro
59. alled by reversing the above procedure Do not touch the surfaces of the gas filters with fingers CAUTION The chopper wheel 42 should be treated with care as the gas filters can be broken by rough handling b Install a new chopper box scrubber see section 6 31 b c Replace the transducer into the 4100 chassis in the same position see section 6 30 d Setup and calibrate transducer according to section 6 41 6 34 Gfx mirror cleaning and replacement Removal Refer to figure 6 18 a Remove the transducer from the 4100 chassis see section 6 30 b Remove the four mirror bezel fixings 47 1 4 turn at a time to prevent stressing the mirror and carefully remove the bezel 48 without letting the mirror 49 fall out c Clean with a soft tissue The tissue may be moistened with acetone or an aqueous detergent to help cleaning If necessary replace the mirror d Inspect the two o rings 50 51 for damage or degradation replace if necessary e Repeat the above for the other mirror f Whilst the mirrors are off inspect the inside surface of the cell and clean if necessary see section 6 35 Refitting a Re assemble according to figure 6 18 and carefully tighten bezel retaining screws 1 4 turn at a time to avoid stressing the mirror b Replace the transducer into the 4100 chassis in the same position see section 6 30 c Setup and calibrate according to section 6 41 6 41
60. ard guides 11 The front card frame fixes to two studs in the base of the chassis The rear card frame is suspended from the top rear of the chassis using two screws 3 which fix into threaded inserts in the chassis The Motherboard 9 is suspended between the two card frames The Motherboard has threaded inserts which are used to fix it to the card frames using four screws 5 Three fixings are provided at the rear of the Motherboard and one at the front The front of the Motherboard protrudes through the front card frame to give support in the region of the connector Between one and four Terminal boards 6 may be fitted These plug into the Motherboard but the connector which is presented to the customer at the rear of the chassis is sandwiched between the rear of the chassis and the rear card frame Thus the Terminal boards form an integral part of the card frame The following boards plug into the Motherboard and are supported by card guides Refer to figure 6 4 Power supply 19 Microprocessor 6 Sensor interface 2 Three option boards 3 4 5 Multiplexer board 1 The Power supply has a metal case and is given additional support by a screw Figure 6 4 18 which fixes it to the card frame All boards which plug into the Motherboard have handles to aid extraction except the Microprocessor board and power supply Power connector Refer to figure 6 4 The power connector 9 provides mains voltage selection fusing and a
61. as been bent during fitting Replace processor board using the procedure in section 6 15 of this manual Do not replace the instrument cover at this stage Power up the system and observe the LED s 13 All the red LED s should be extinguished in sequence within 4 seconds of powering on If LED D3 remains on then either the IC s are swapped installed within the wrong sockets or some of the IC pins may not be seated correctly If the IC s are seated correctly and the LED D3 is still illuminated on power on then the IC s may have suffered static damage during fitting If all the red LED s are extinguished then replace the instrument cover in accordance with section 6 1 of this manual Under some circumstances additional instructions may be provided with the upgrade kit defining data modifications required through the user interface This would normally be the case if anew EEPROM 8 has been supplied as part of the upgrade If these instructions are provided then these should be executed now The upgrade is now complete 7 2 7 2 1 EDIT ID DEL HIST CAL TXD CALIBRATE DEF CAL RECONFIG UPLOAD EDIT CAL DOWNLOAD EDIT TC BASE OFFSET Figure 7 2 Instrument Configuration Menu Map Software configuration menu The QuickStart manual contains comprehensive instructions on all user functions available on the instrument A separate hidden menu is available for use only by trained service personnel This menu giv
62. as sensor module sideways and lift to remove Refitting Use reverse procedure Refer to QuickStart manual for calibration instructions 6 29 Control paramagnetic transducer Refer to figure 6 15 Note The 01156A 000 paramagnetic transducer includes the 01 156 904 PCB The temperature compensation is specific to this combination therefore the PCB supplied with the 1156A 000 must remain paired with it CAUTION The paramagnetic transducer and its cell should not be subjected to mechanical shock which may result in damage to the cell suspension Removal a Remove control paramagnetic gas sensor module see section 6 28 C Remove sample connections 6 from paramagnetic cell 2 d Disconnect ribbon cable 7 from PL1 on 01156 904 PCB 1 f Remove three off paramagnetic transducer fixing screws from the underside of the module bracket 3 9 The paramagnetic transducer may now be removed Refitting 6 34 Use reverse procedure Refer to QuickStart manual for calibration instructions Figure 6 16 1210 High sensitivity Gfx gas sensor assembly 6 35 6 30 6 31 6 36 Gfx gas sensor module assembly Removal a Remove the instrument cover see section 6 1 b Refer to figure 6 20 Remove the auxiliary power connector 10 and the signal connector 11 from the house keeping PCB c Referring to figure 6 16 remove the viton tubing from the transducer inlet 25 and outlet 26 gas connections Loosen the four transdu
63. autocalibration units When the internal autocalibration feature paramagnetic only is supplied a valve manifold is mounted in the sample gland plate see figure 2 4 This provides ports for sample inlet and outlet plus additional inlets for two calibration gases The autocalibration manifold is installed on gas stream 1 Again a single sample inlet is provided on each gas stream This option is not suitable for use with toxic samples Pressure or flow driven external autocalibration units The gland plate supplied for the external autocalibration option see figure 2 5 There are no inlets for calibration gas Instead an electrical connector carries drive signals which may be used to control solenoid valves mounted outside the instrument case 2 9 Sample port sizes and thread types are given in table 2 1 Sample Inlet 1 PP Sample Sample Sample Sample Outlet Outlet 2 Outlet 3 Outlet 4 AN WARNING Figure 2 3 Sample gland plate without auto calibration 2 10 7 N N y cc O Oo Sample Inlet 1 SII o Sample Sample Outlet 3 Outlet 4 Low Cal Gas WARNING HO Sample 3 Outlet NN f N N J NGA SAMPLE LOW H CAL CAL 2 3 6 RNING
64. cer washer nut fixings and slide the transducer to the right and lift free from the 4100 chassis Refitting a Use reverse procedure CAUTION Ensure that the correct signal and power ribbon cables are fitted to the correct sockets on the transducer house PCB before applying power see figure 6 20 b See section 6 41 for the transducer setup and calibration procedure Gfx Source replacement Refer to figure 6 17 Removal a Remove the transducer from the 4100 chassis see section 6 30 b Remove the three hex cap screws 30 and carefully withdraw the source 31 from the chopper box 3 Retain the three spacers 32 which will fall away Remove the source plug from the house keeping PCB by squeezing the sides and easing upwards WARNING Hot surfaces are present on the chopper box 3 and IR source 31 Refitting a To replace the new source first ensure that the o ring 33 is in position in the o ring groove on the source Insert the three screws 30 into the source body and slide the three spacers 32 onto the screws Offer up the assembly to the chopper box 3 and push well home Tighten the screws and insert the plug into the house keeping PCB source socket see figure 6 20 Replace Chopper Box Scrubber Install a new scrubber bag 34 by removing hex socket blanking plug 35 withdrawing and discarding the old scrubber Remove the new scrubber bag from its protective foil bag and in
65. connect ribbon cable 34 from PL2 on 01156 904 PCB 15 Da Disconnect gas sensor signal cable 36 from PL1 on 01166 901 PCB 13 Remove four fixing screws 9 for transducer bracket and remove transducer bracket complete with paramagnetic transducer 17 and associated boards 13 15 h Remove three off paramagnetic transducer fixing screws 16 from the underside of the transducer bracket 10 i The paramagnetic transducer magnet frame 17 may now be removed j Remove the 01156 904 PCB 15 by releasing plastic fasteners k Pair 01156 904 PCB with magnet frame assembly by plugging in 10 way connector from magnet frame assembly to PL2 on 01156 904 PCB 15 e Refitting 6 32 Use reverse procedure Figure 6 15 Control paramagnetic gas sensor module 6 28 Control paramagnetic gas sensor module Removal Refer to figure 6 4 a b Disconnect gas sensor module signal cable from Multiplexer board connector 23 Disconnect gas sensor module power cable from Multiplexer board connector 24 Note It may be necessary to lift the Multiplexer board 1 out of its card guides to gain access to the power cable connection All other connections to the Multiplexer board may be left connected during this operation Refer to figure 6 15 c Disconnect sample tubing from cell connectors 6 Identify inlet and outlet for ease of re connection 6 33 d Loosen four off gas sensor module fixing nuts e Slide g
66. ctor and ensure that voltage selector is correctly set Ensure that all protective earth connections are secure prior to refitting the cover Figure 6 5a Solenoid valves and manifold 6 12 Autocalibration connections WARNING The sample and calibration gases used with the instrument may be toxic or asphyxiant Ensure that gases are turned off and the instrument is flushed with inert gas before opening the instrument le system to air 6 13 6 12 1 Manifold block and solenoid valves 6 14 Refer to figure 6 5a Removal Refitting Disconnect the sample inlet and outlet connections to the instrument Remove the cover see section 6 1 Disconnect the solenoid valve electrical connectors 10 11 from the motherboard Slide the hose clip on the two plastic pipe adaptors 8 fitted to the manifold block back up the sample tube by opening the spring clip with pliers Disconnect the sample tubing from the plastic adaptors Remove the two fixing screws 5 for the manifold block 1 Lift the manifold block away from the gland plate Remove the solenoid valve fixing screws 9 two per solenoid valve Remove the solenoid valve from the manifold block Note that the o rings 4 may become dislodged from the solenoid valve while removing Use reverse procedure NOTE Ensure that the o rings are in position when refitting solenoid valves to manifold block 6 12 2 External Autocal Relay PCB Refer to
67. d all calibrations are retained indefinitely CALIBRATE MAN CAL LOW m HIGH PRESS HISTORY 1 LOW HISTORY QR LOW HIGH HISTORY HIGH m CHECK LOW P OFFSET HISTORY CHECK HIGH 7 AUTO CAL 77777 ONE CYCLE SET UP CAL PARM SET ALARM ASSIGN m RELAYS ANALOGUE M DISPLAY m OUTPUTS RELAYS ANALOGUE M ALARMS DIAGNOSTICS L_ ip CLOCK UTILITY o UTILITY1 NEW PASS SUPERVISOR OPERATOR COMMS SET FRAME FREQ SET COMMS PARMS WIN SELECT SCRN UDEF DEFINE SCRN VARS EDIT KEY FUNCS TIME CONST UTILITY 2 LOW amp HIGH TOL ALARMS DISPLAY ALARMS ALARM HISTORY FAULTS DISPLAY FAULTS FAULT HISTORY For Pm oxygen Purity Module ONLY 1 4 5 NAMEric Uae mpg ace menu map When numeric data input is required then a field of individual digits will be offered to the user Each of these digits is edited independently using the arrow keys gt lt For numeric information each digit position may be changed to i Any number in the range 0 to 9 ii A decimal point iii A minus sign The minus sign may only be positioned in the first character The position of the decimal point may be changed from that offered as a default Any digit position except the right most digit may be used for the decimal point The following are examples of valid numeric data entries 2033 0100 1 4 6 1 5 1 6 The following is an e
68. d around the dumb bell so that the torque acting upon it due to presence of oxygen in the sample is balanced by a restoring torque due to the feedback current in the coil The feedback current is direct proportional to the volume magnetic susceptibility of the sample gas and hence after calibration to partial pressure of oxygen in the sample A voltage output is derived which is proportional to the current Linearity of scale also makes it possible to calibrate the instrument for all ranges by checking at two points only For example accurate calibration is obtained by using pure nitrogen for zero and air for setting the span at 20 95 All the materials in contact with the sample are highly resistive to aggressive compounds The internal design of the cell body has a special flow channel to improve the flow characteristics while the volume is kept to a minimum to provide an excellent response time The optical carrier 4 has provisions for moving of the photocell mount for setting the initial zero and also incorporates the LED light source and temperature sensing devices The Electronics The control electronics perform all the functions necessary to provide operation of the transducer and to produce an electrical output proportional to the partial pressure of oxygen Interfacing for inputs and output is via a 16 way IDC connector The electronic PCB 01156904 includes the following circuit functions a constant current source the sign
69. dentified a problem then replace the transducer and verify instrument performance 5 3 4 Measurement faults 5 18 Symptoms Unable to perform zero calibration Unable to perform span calibration Calibration failure fault indicated Low instrument sensitivity Poor instrument accuracy Measurements and Diagnosis a Verify contents of the calibration gas samples have been correctly entered into the instrument software and that calibration gases are correctly connected Check that calibration gas supply is not exhausted Increase the calibration tolerance if necessary Correct or replace where necessary and perform instrument calibration to verify performance Check that the concentration of the calibration sample corresponds with the concentration specified in the autocalibration configuration Perform an ONE CYCLE autocalibration to clear the fault Verify correct operation of autocalibration valves if fitted Perform a leak test to verify cross seat leakages Correct fault in accordance with section 5 2 12 if necessary Correct or replace where necessary and perform instrument calibration to verify performance Verify that there are no leaks in the internal pipe work and that flow meters operate correctly if fitted Correct or replace where necessary and perform instrument calibration to verify performance Verify that there are no blockages in the sample filter if fitted and internal flow restrictors Correct or rep
70. e fault is located on one of the remaining optional output boards then replace the faulty output PCB and or its associated terminal board and re validate instrument performance Replace the microprocessor PCB and re validate instrument performance Note Replacing the microprocessor PCB will require reconfiguration of the analyser Refer to section 7 2 Check electrical continuity between the output boards and the associated terminal boards via the instrument motherboard connectors Replace the mother board PCB if this is faulty and re validate instrument performance Replace the motherboard PCB and re validate instrument performance 5 2 8 Analogue output readings not accurate Symptoms Analogue output readings inaccurate or do not follow required composition changes Measurements and Diagnosis a Check that the analogue output channel assignments are correctly configured and enabled within the instrument software Correct where necessary and re validate instrument performance Check that interconnecting wiring is correctly installed within the screw terminal block within the external two part connectors This is conveniently accomplished by removing the connector and checking operation at the connector pins Correct where necessary and re validate instrument performance Ensure that the signal interface board optional output boards and associated terminal boards are correctly located within their connectors on the mother board
71. e table 6 1 for details The location of the links is shown in figure 6 13 Table 6 1 Zirconia control board link settings Link on 00700 902 PCB Setting for 703 cell Setting for 704 cell After the replacement of this component the zirconia gas sensor module will need to be set up See section 6 23 1 below 6 23 1 Setting up Zirconia Gas Sensor Module Once the Zirconia Gas Sensor Module has been refitted to the xentra 4100 it must be set up in accordance with the following procedure if either the House Keeping PCB 00700902 or the Zirconia sensor 00703000 or 00704000 has been replaced For multi cell analysers power up only one sensor at a time Refer to figure 6 13 a Ensure that the links LK1 to LK10 on the house keeping PCB are set correctly see table 6 1 Ensure that RV1 is initially set fully counter clockwise ccw b Switch the instrument on whilst monitoring the voltage at TP1 6 27 6 28 temperature with respect to TP3 ground The reading should rise steadily Make the following adjustments quickly For zirconia sensor 00703000 adjust RV1 temperature to obtain a reading of 7465mV 20mV For zirconia sensor 00704000 adjust RV1 temperature to obtain a reading of 5898mV 20mV Ensure this voltage is not exceeded Use the xentra 4100 display to show the diagnostics for the gas sensor module MENU SETUP DISPLAY DIAGNOSTICS and select the CELL TEMP diagnostic for the module For zirconia sensor 00703
72. e work and that flow meters operate correctly if fitted Correct or replace where necessary and perform instrument calibration to verify performance Verify that there are no blockages in the sample filter if fitted and internal flow restrictors Correct or replace where necessary and perform instrument calibration to verify performance Verify that the instrument exhaust port is not restricted and that the instrument is not being pressurised above ambient pressure Correct or replace where necessary and perform instrument calibration to verify performance Check the cell output voltage using pins 9 and 10 on connector PL1 on the transducer house keeping PCB see drawing 01156 102 Check that the output varies from OV to 0 21V as a zero and air sample are applied to the sample input port for the specific gas stream Correct or replace transducer and PCB where necessary and re verify performance Verify continuity of interconnecting wiring from the transducer cell to the transducer house keeping PCB and from the transducer to the MULTIPLEXER PCB Correct or replace where necessary and re verify instrument performance 5 25 Check the cell output shown in the instrument diagnostics display matches the output voltage given on pins 9 and 10 on connector PL1 of the transducer housekeeping PCB see also drawing 01156 102 Fault is likely to be either the Sensor Interface PCB or the Multiplexer PCB Identify and replace the faulty PCB
73. ed continuously The microprocessor board contains a watchdog timer which must be re initialised by the software every half second If the software fails to re initialise the watchdog the microprocessor will be reset thus extinguishing the green LED momentarily If the software can not run eg because the RAM has failed the microprocessor will be continually reset under these circumstances the green LED appears to flash The two red LED s at the top of the microprocessor board are extinguished by the software when memory checks have been completed following a reset Following successful memory checks the message SYSTEM OK will appear on the display Table 2 2 shows the sequence of LED states TABLE 2 2 MICROPROCESSOR LED STATES State D3 D2 D1 GREEN RED RED Initial state ON ON OFF microprocessor is reset Reset line released RAM test OK EPROM test OK 2 2 5 Sensor interface board The sensor interface board consists of the following digital outputs for multiplexing of signals an A to D convertor to receive multiplexed analogue signals a digital input for multiplexed digital signals two isolated analogue outputs and three volt free relay contacts The board provides an identification code which the microprocessor can read to identify that the board is fitted is of the correct type 2 2 6 Option boards Option boards are depopulated versions of the Sensor interface board Which have dual relays plus dual isolated curr
74. ed in Table 1 7 Table 1 7 Displaying diagnostic information L MENU to obtain top level menu CALIBRATE SETUP L lt ENTER ALARMS FAULTS SET ALARM ASSIGN L ENTER DISPLAY UTILITY OUTPUTS ALARMS L ENTER DIAGNOSTICS ID 12 CELL EMF L gt to view further diagnostics information 0 234 Volts 8 I2 CELL TEMP L gt to view further diagnostics information 35 5 C 8 I1 CO2 DIF SIG L gt to view further diagnostics information 0 003 Volts 8 I1 CO2 GAS SIG L gt or to view further diagnostics information 0 900 Volts 8 L MEASURE to return to measurement displa SECTION 2 INTRODUCTION LIST OF CONTENTS Section Page 2 1 Mechanical Overview 002 ees 2 3 2 2 Electrical Overview XX Xa ama BAL AA na ak sana baud Khan 2 13 LIST OF FIGURES Figure Page 2 1 Schematic for flow driven Zr sample system 2 8 2 2 Schematic for pressure driven Zr sample system 2 8 2 3 Sample gland plate without autocalibration 05 2 10 2 4 Sample gland plate with autocalibration aaa 2 11 2 5 Sample gland plate with external autocalibration 2 11 2 6 Electronic system block diagram 0c eee eee eee 2 14 2 1 2 2 NOTES 2 1 4 PRODUCT OVERVIEW Mechanical Overview General Refer to figure 6 1 The Xentra consists of a sheet metal chassis 4 and cover 3 fixed with either 9 Xentra 4102 or 11 Xentra 4104 screws 2 The chassis contains
75. ee eee 6 19 Motherboard removal s ad toes cheng Mees AYANG oe wis dened Soe ig ADAN ADA 6 21 Zirconia gas sensor MOG aaGauisaetote Paes ate TADO eee AA 6 22 Pressure driven zirconia gas sensor module 6 24 Flow driven zirconia gas sensor module 200005 6 25 Zirconia control boardi sariu aiea eels NAYAN hd E hg ws ig ad 6 26 Purity paramagnetic gas sensor module 200005 6 30 Control paramagnetic gas sensor module 00000 eee 6 33 1210 High sensitivity Gfx gas sensor module 6 35 Gfx 1210 chopper box assembly 8n nd Maan GG wag Boas 13d wos Anna 12 6 38 High sensitivity Gfx optical cell assembly 00005 6 42 1210 Gfx detector assembly aaa kab eben KN tae 6 45 Gfx 1210 House keeping PCB assembly 20000005 6 49 Typical Gfxsignal trace erensia wer rer eee pre wre eee we ee er cree ere 6 51 Gfx pressure driven sample system 00000 cece eee 6 53 Gfx flow driven sample system 2 0000 cee eee eee 6 53 6 4 NOTES 6 PARTS REPLACEMENT PROCEDURES 6 1 Cover Figure 6 1 Cover removal Refer to figure 6 1 Removal a Remove 6 off screws 2 3 on each side of chassis 8 of screws for long chassis b Loosen 3 of screws on rear of chassis 1 c Lift rear of cover to clear rear screws and slide cover backwards to remove Refitting a Ensure that conductive EMC gasket figure 6 3 1 is intact at
76. efitting Use reverse procedure Terminal board Refer to figure 6 9 Removal Remove two power connector fixing screws figure 6 4 8 and partially withdraw power connector from rear of chassis to allow access to Motherboard connections b Remove Switched mode power supply Microprocessor board Sensor interface board and option boards c Disconnect the following from the Mother board keypad ribbon cable power connector solenoid valves internal fan and external fan d Remove Multiplexer board see section 6 16 e Remove two off rear card frame fixing screws 3 f Remove two of PL6 D connector hexagonal pillars 2 from rear of chassis 9 Remove Motherboard earth connection from earth stud in rear of chassis 1 h Remove two off front card frame fixing nuts 4 i Lift front card frame clear of threaded studs in base of chassis 4 and withdraw complete card frame assembly frontwards and remove j Remove the required Terminal board s by unplugging from Motherboard and withdrawing through rear card frame Refitting Use reverse procedure NOTE Ensure that customer terminals are engaged in rear of chassis when refitting card frame assembly 6 19 Mother board Refer to figure 6 9 Figure 6 9 Motherboard removal Removal a Remove all terminal boards see section 6 18 b Remove three rear card frame fixing screws and front card frame fixing screw 5 Refitting Use reverse
77. ent outputs 2 2 7 2 2 8 2 2 9 2 18 Multiplexer board The multiplexer board buffers signal from the gas sensor modules provides offset and scaling and routes them to the Sensor interface board via the Motherboard Routing of the signals is performed using multiplexers under control of the microprocessor Electrical power is provided to the gas sensor modules from the Multiplexer board The multiplexer board also provides signal routing and multiplexing for the two external analogue inputs The pressure transducer sites SK1 amp SK2 on the multiplexer board are not used on the 4100 A 2 5V voltage reference is provided for span compensation of the electronics this signal is read via the A D convertor and the compensation performed by software The control lines from the Sensor interface board are fed into a D type latch and latched in under control of the microprocessor to drive the solenoid valves Via a drive transistor Mother board The Mother board has no active components It is used to connect the following items Switched mode power supply microprocessor board Sensor interface board option boards Terminal boards Multiplexer board transformer fans and solenoid valves Two versions of the Mother board are available one provides for one option card and one provides for three option cards The Mother board carries a fuse for the transformer auxiliary winding which is accessible from the rear of the chassis
78. entify the cause of damage or foreign bodies and replace the relevant parts before rechecking that the motor is rotating freely Note that at very low temperatures correct chopper speed may take some time to achieve If the motor is not jammed and the D13 LED is still off check the continuity of the cable connections Check that the motor connector from the chopper box is fully inserted If continuity is satisfactory replace the motor If the LED is still off replace the Housekeeping PCB The D11 LED source OK LED is off Measurements and diagnosis a Check the fuse F1 Replace the fuse if it is blown and retest If the fuse blows again then replace the Housekeeping PCB If the fuse is OK then check that the source resistance is approximately one ohm Replace the source if the resistance is incorrect Check that the voltage across the source is between 1 9 and 2 1 Vdc If not then replace the house keeping PCB 5 6 4 Measurement faults Symptoms Unable to perform zero calibration Unable to perform span calibration Calibration failure fault indicated Low instrument sensitivity Poor instrument accuracy Measurements and Diagnosis a Verify contents of the calibration gas samples have been correctly entered into the instrument software and that calibration gases are not empty and are correctly connected Increase calibration tolerance if necessary Correct or replace where necessary and perform instrument ca
79. eplacement 200055 6 39 Gfx Chopper Wheel Replacement 0005 6 40 Gfx Mirror Cleaning and Replacement 6 41 Gfx Optical Windows Cleaning and Replacement 6 43 Gfx Cell Cleaning and Replacement 6 43 Gfx Detector PCB Assembly 2200 cece eee 6 44 Gfx Chopper Box PCB Assembly 0000000 0 6 46 Gfx Housekeeping PCB Assembly 2200055 6 47 Gfx Signal Processing PCB Assembly 6 48 Gfx Set Up and Calibration 2 6 49 Pressure Driven Gfx Sample Pipework 6 54 Flow Driven Gfx Sample Pipework 055 6 54 Figure 6 1 6 2 6 3 6 4 6 5a 6 5b 6 6 6 7 6 8 6 9 6 10 6 11 6 12 6 13 6 14 6 15 6 16 6 17 6 18 6 19 6 20 6 21 6 22 6 23 LIST OF FIGURES Page Cover removal nauau annaa KANG tee sue ars evo eee DOG PDA 6 5 Exploded VIEWSOL fascia sawise agad NOR gd awe AGA wos suas ee N Ges 6 6 Keypadirbbon Cable pasa atch ata ee area ee Gea sa ewe ee 6 8 Card frame transformer and IEC appliance adaptor 6 12 Solenoid valves and manifold 00 0c 6 13 External autocalibration relay PCB 0 2c eee ee eee 6 15 Ee ad eye ayer et a ep Stee NANA NANA PAA 6 16 INt NalifaNeccc te eee eke ee eR CR MORA ee ee BANAL ABA n E a 6 17 Multiplexer board fuses 0 cee eee e
80. ermal shock to the cell and limits power delivered to the cell under fault conditions These circuits are described in more detail Thermocouple Amplifier The cell thermocouple connects to terminal block TB1 Copper ground planes run under the thermocouple amplifier IC1 to improve EMC IC1 contains the cold junction compensation The temperature of the thermocouple can be found by measuring the voltage on test point TP1 with respect to TP3 and using the the table from the AD595 data sheet If the thermocouple is open circuit or reverse connected IC1 pin 12 is pulled low to inhibit the heater circuit The cell temperature is set by RV1 in conjunction with LK2 and LK3 The Zirconia electrode temperature is available for Nernst equation calculations at PL2 pin 12 The temperature error amplifier IC3 pin 14 has an output of 2 2V C which drives the heater controller Variable resistor RV2 in conjunction with LK1 compensates for the temperature difference between the Zirconia electrode and the thermocouple RV2 is adjusted at the time of test to give the correct cell temperature indication determined by the Nernst equation Heater Voltage Measurement The circuit around IC3 pin 1 rectifies the heater voltage pulses The polarity of the AC input is detected by IC6 pin 2 and is used to control the sign of the gain of amplifier IC3 Heater Power Measurement The positive heater pulses are converted into a current by R30 and then drawn thro
81. es access to higher instrument configuration functions Access to this level of instrument configuration should not be made available to users in normal operation Access to the special configuration menu Access to the special configuration menu is via two security screens a An encrypted sequence of keys are pressed to indicate to the instrument that access is required to the special configuration menu as follows Ensure that the instrument is showing the measure display if not the press MEASURE The following sequence of 7 keys must be pressed in order within 10 seconds to access the second security screen b t v ENTER QUIT MEASURE 4 MENU b The system will then prompt for a special password before giving the user access to the menu The appearance of the password screen and its operation is exactly the same to that used in normal password operation The password for this level is 1812 7 5 7 2 2 7 2 3 7 2 4 7 6 When the password has been successfully entered the standard instrument menu will be displayed with an additional field labelled SC CALIBRATE SETUP ALARMS FAULTS SC After any function is performed under the Special configuration menu the user must return to this menu level Pressing MENU again will remove the SC option from the menu thus preventing any unauthorised access The special configuration menu is entered by selecting the SC option The following menu will
82. esent then check the continuity of the keypad ribbon cable and replace if necessary Invertor supply faulty Measurements and diagnosis Check the output voltage of the invertor pin 3 wrt pin 5 Note that this is a sinusoidal waveform at 35 kHz ensure that the test equipment is suitably specified Nominal open circuit voltage 1 KV Normal operating voltage 300V If the output voltage is not present then replace the invertor PCB or the entire keypad PCB 5 2 3 LCD back light lamp faulty Measurements and diagnosis Check the output voltage from the invertor PCB pin 3 wrt pin 5 If this voltage gt 500 V then check the back light connections and or replace LCD Display illuminated but no text Switched mode power supply faulty Measurements and diagnosis Check the power supply rail voltages using the test points on the multiplexer PCB The following test points on the Multiplexer PCB should be used TP05 wrt TPO1 5 05V 0 25V If supply voltage is low or is not present then disconnect the following units in order to determine whether the 5V rail is being pulled down Ensure that the instrument is switched off before connecting or disconnecting PCB s i Gas sensor modules ii Option boards iii Sensor interface board iv Keypad ribbon cable v Microprocessor board vi Multiplexer board by elimination of other possible causes Microprocessor PCB faulty Measurements and diagnosis Check that the red LED s D
83. f either operation an error message appears to the effect that upload or download has failed then check the configuration of the links on the Gfx transducer house keeping PCB see section 6 41 A default set of definitive calibration data is loaded by the reconfiguration procedure 7 2 but this does not guarantee that the instrument will perform within specification However once a successful download has been performed correct operation is guaranteed DEF CAL It should never be necessary to use the DEF CAL function in the field except in the most extreme cases of total data loss This procedure replaces any existing calibration data with a new set of experimental points It stores the absorption values corresponding to the stated concentration of a set of test gases which must be supplied to the instrument in turn Prompts are issued for each pair of values in the order zero span intermediate points Apart from zero low and span high the order of entry is immaterial but there must be a minimum of three different intermediate points Note that immediately the first point is entered all pre existing data are destroyed EDIT CAL It should never be necessary to use the EDIT CAL function in the field except in the most extreme cases of total data loss A simple editor is provided which enables the concentration or absorption co ordinates of a pre existing data set to be modified It does not allow insertion or deletion of points
84. f the instrument sensitivity is low then perform the instrument measurement fault checks in section 5 3 4 h If none of these checks rectify the problem then replace the transducer and verify performance Flow faults Symptoms Slow instrument response Drift Noise Flow sensitive results Measurement and Diagnosis a Verify that the sample flow rate through the transducer is in the range 100 250 ml min and is stable Verify that any flow stability problems encountered are not produced by any sample conditioning system used prior to sample entry into the instrument Particular attention should be made to knock out pots sample pumps chillers and filters Correct or replace where necessary and re verify instrument performance By performing a leak test verify that the internal pipe work within the instrument is leak tight Pay particular attention to flow meter leakages if these are fitted Correct or replace where necessary and re verify instrument performance CAUTION The paramagnetic transducer should not be pressurised above 10 psig 70 kPag When leak testing the pipework care should be taken that the paramagnetic cell is pressurised and depressurised slowly Failure to do this may result in damage to the cell Verify that the optional sample filter if fitted is clean and not blocked Correct or replace where necessary and re verify instrument performance Verify that the orifice flow restrictors withi
85. from the 4100 chassis see section 6 30 Remove the cell assembly see section 6 32 Remove the detector assembly see section 6 37 Remove the mirrors See section 6 34 Clean the inside of the cell tubes using a plug of soft tissue pushed through the cell The tissue may be moistened with acetone or an 6 43 6 37 6 44 aqueous detergent to help cleaning Whilst disassembled inspect the windows mirrors and o rings Clean or replace as necessary Refitting Re assemble as above in reverse order using a new detector scrubber Replace the chopper box scrubber once reassembled see section 6 31 b CAUTION The chopper box 3 and detector light pipe 19 are sealed enclosures Once opened a new scrubber must be fitted Replace the transducer into the 4100 chassis in the same position see section 6 30 Setup and calibrate according to section 6 41 Gfx detector PCB assembly Removal Refer to figure 6 16 a b c Remove the transducer from the 4100 chassis see section 6 30 Remove the insulation retaining clip 2 and insulation 1 from the chopper box Remove the detector ribbon connector and earth wires 23 from the detector box 22 Remove the detector scrubber 5 and the detector box 22 by loosening the three fixings 21 Move the cell assembly away from the chopper box by removing the three screws 4 and loosening the four cell clamp screws 15 Refer to figure 6 19 d L
86. front of chassis b Ensure that tongues at front of cover are fully engaged in chassis Lower rear of cover ensuring that cover is located under rear fixing screws 1 c Refit screws 2 to side of cover d Retighten all screws NOTE Following satisfactory performance checks the appropriate tamper proof label should be attached 6 5 6 2 6 6 Fascia Removal 2 KAN NG EN Figure 6 2 Exploded view of fascia Refer to figure 6 2 Removal a b C d Remove cover See section 6 1 If flow tubes are fitted 9 10 remove flow tubes see section 6 6 Remove 8 off screws figure 6 3 8 which fix the fascia to the chassis Access to the bottom four screws may be gained via the slots in the underside of the chassis 14 using a ball end hexagon key Lift fascia directly away from chassis to clear flow tube bottom end blocks 7 8 Disconnect keypad ribbon cable figure 6 3 2 from the Keypad PCB connector 45 The fascia may now be lifted away from the chassis Whilst working on the fascia lay it on a soft surface to prevent damage Refitting Use reverse procedure 6 3 6 4 NOTE Ensure that conductive EMC gaskets 31 are intact and securely fitted Keypad PCB and rubber mat Refer to figure 6 2 Removal a Remove fascia see section 6 2 b Remove display connectors 18 19 c Remove four keypad fixing screws 20 d The keypad may now be lifted away from
87. ic signals available for the Pm O Control transducer Table 5 5 Diagnostic signals for the Pm O Control transducer Diagnostic Description Typical level Range CELL EMF Cell output volts 0 2 V 0 1 to 1 2 V CELL TEMP Cell temperature 35 C 5 to 70 C Fault messages Table 5 6 shows a list of the indicated fault conditions for the Pm O Control transducer Table 5 6 Fault messages for the Pm O Control transducer or or or Fault indicated Possible causes Recommended action CELL VOLTS HIGH Faulty component See section 5 4 3 LOW CAL CHK OUTSIDE TOL CELL VOLTS LOW Faulty component See section 5 4 3 CELL TEMP HIGH Check ambient temperature lt 40 C See also section 5 4 3 Ambient temperature too high or faulty component CELL TEMP LOW Faulty component See section 5 4 3 HIGH CAL CHK OUTSIDE TOL User set low or high See section 5 4 4 calibration tolerance has been exceeded during auto calibration HI CAL CHK The gas concentration Respecify the OUTSIDE RANGE in the autocalibration calibration gas configuration is outside concentration LO CAL CHK of acceptable limits OUTSIDE RANGE HI CAL RESULT The autocalibration See section 5 4 4 OUTSIDE LIMITS results differ from the existing values by LO CAL RESULT more than the OUTSIDE LIMITS tolerance limits 5 4 3 Transducer faults Symptoms No response from transducer
88. ilure to do this will result in fracture of the flow tube WARNING The sample and calibration gases used with the instrument may be toxic or asphyxiant Ensure that gases are turned off and the instrument is flushed with inert gas before opening the instrument le system to air Removal Remove gas sensor module from immediately behind flow tubes if fitted Remove fascia see section 6 2 Disconnect sample tubing from plastic adaptor Remove bottom flow tube end block 7 8 and fixing screws 15 The end blocks may now be withdrawn from the fascia Remove end block 7 8 Qr gt oocn Refitting Use reverse procedure Sample filter housing Refer to figure 6 2 NOTE Take care to keep the end block spigot and flow tube concentric when removing and refitting failure to do this will result in fracture of the flow tube NOTE The sample and calibration gases used with the instrument may be toxic or asphyxiant Ensure that gases are turned off and the instrument is flushed with inert gas before opening the instrument sample system to air 6 9 6 10 Removal Remove fascia see section 6 2 b Slide spring clip on plastic adaptors fitted to filter housing back up sample tube by opening spring with pliers c Disconnect sample tubing from plastic adaptor d Remove plastic adaptors from filter housing this may be supplied with the new housing e Remove fixing screws 25 Refitting Use reverse procedure
89. in 12 Cell temperature Pin 10 Cell output EMF The cell temperature output on pin 12 of PL2 is scaled to give 1 0 05 mV per C If the displayed signals are incorrect then the fault may lie within either the Multiplexer PCB or the Signal Interface PCB Correct or replace where necessary and verify instrument performance Check link settings on the house keeping PCB Check that the sensor temperature is correct for the cell type and that the temperature control is operating The normal operating temperature for the Zr704 cell is 575 C and for the Zr703 cell is 720 C If faulty then check the cell thermocouple connections on pins 4 and 5 of terminal block TB1 Correct or replace the zirconia cell and or house keeping PCB and verify instrument performance Check that the cell output EMF signal on pin 10 of connector PL2 reflects the input gas composition when nitrogen and air gas samples are applied to the inlet port g If none of the above tests have identified a problem then replace the transducer and verify instrument performance 5 5 4 Measurement faults Symptoms Unable to perform zero calibration Unable to perform span calibration Calibration failure fault indicated Low instrument sensitivity Poor instrument accuracy Measurements and Diagnosis a Verify contents of the calibration gas samples have been correctly entered into the instrument software and that calibration gases are correctly connected Correct or re
90. instrument is warming up or being calibrated via the internal autocalibration facility Icons also indicate the presence of alarms or faults If the fault or alarm icons appear on the measurement display the exact nature of the fault or alarm may be determined via the user interface see 1 8 Displaying alarms present and 1 9 Displaying faults present 1 4 2 The Xentra keypad User input to the Xentra instrument is via the Xentra keypad A view of the keypad is given in figure 1 4 1 7 xentra Figure 1 4 The Xentra keypad The functions of the keys on the Xentra keypad are as follows Measure key Pressing the MEASURE key at any time returns the instrument to the default measurement display see section 1 4 1 Menu key Pressing the MENU key activates the Xentra top level menu Quit key Pressing the QUIT key aborts the current activity and returns the user interface to the menu level at which the activity was selected Pressing the QUIT key while in the top level menu has no effect Edit key Pressing the EDIT key and entering the appropriate password will give immediate access to the edit functions provided to modify the text on the measurement display This includes the names of measured variables the measurement units the displayed precision and the filtering applied 1 4 3 gt lt keys Within menu displays the user highlights the desired option using the arrow keys g
91. instrument performance Verify that the transducer is not contaminated particularly with condensed water Correct or replace transducer if necessary and re verify instrument performance Replace transducer and verify that the problem is corrected Zirconia transducer faults This section of the manual covers likely fault symptoms associated with the zirconia transducer assemblies The faults are categorised by the observed symptoms 5 27 5 5 1 Diagnostic measurements 5 28 Table 5 7 shows a list of the diagnostic signals available for the zirconia transducer assembly Table 5 7 Diagnostic signals for the zirconia transducer Diagnostic Description Typical level Range CELL EMF Cell output volts 50 to 400mV CELL TEMP Cell temperature 575 or 720 C 525 to 625 C or 670 to 770 C Zirconia cell temperature This is the cell electrode temperature displayed in C A XXX fault is indicated if cell temperature exceeds 800 C or cell temperature less than 500 C after 3 minutes from switching on The normal operating temperature for the Zr704 sensor is 575 C The normal operating temperature for the Zr703 sensor is 720 C Zirconia cell EMF This is the voltage output of the zirconia cell The correct voltage can be determined from a knowledge of the sample gas concentration and the cell temperature using the Nernst equation shown below Note that the output of the cell is nominally zero with air a
92. kStart Manual for calibration instructions 6 21 Pressure driven zirconia inlet pipework with restrictor assembly Refer to figure 6 11 6 23 note arrow direction PI Figure 6 11 Pressure driven zirconia gas sensor module 6 24 WARNING The surface of some components within the zirconia gas sensor module assembly are hot Switch off the electrical power and allow 10 minutes for the zirconia cell to cool before servicing module Removal a Slacken the three nuts 5 on the tee piece restrictor assembly 1 b Note the direction of the arrow on the restrictor assembly 1 c Carefully pull out the sample pipework and remove the restrictor assembly 1 d Slacken off the connector at the rear of the chassis amp remove the sample inlet pipe Refitting a Use reverse procedure ensuring arrow on restrictor assembly 1 is pointing in the direction of the sample flow as before 6 22 Flow driven zirconia inlet pipework without restrictor Refer to figure 6 12 Figure 6 12 Flow driven zirconia gas sensor module NOTE The flow driven system is non restricted and does not have a bypass The tee piece restrictor figure 6 11 1 is replaced by a straight connector figure 6 1
93. lace where necessary and perform instrument calibration to verify performance Verify that the instrument exhaust port is not restricted and that the instrument is not being pressurised above ambient pressure Correct or replace where necessary and perform instrument calibration to verify performance g Check the cell output voltage using pins 9 and 10 on connector PL1 on the transducer house keeping PCB see drawing 01156 102 Check that the output varies from OV to 0 21V as a zero and air sample are applied to the sample input port for the specific gas stream Correct or replace transducer and PCB where necessary and re verify performance h Verify continuity of interconnecting wiring from the transducer cell to the transducer house keeping PCB and from the transducer to the MULTIPLEXER PCB Correct or replace where necessary and re verify instrument performance i Check the cell output shown in the instrument diagnostics display matches the output voltage given on pins 9 and 10 on connector PL1 of the transducer housekeeping PCB see also drawing 01156 102 Fault is likely to be either the Sensor Interface PCB or the Multiplexer PCB Identify and replace the faulty PCB where necessary and re verify performance 5 3 5 Stability faults Symptoms Noisy reading Reading drifts Instrument requires frequent re calibration Measurements and Diagnosis a Verify that the sample flow rate through the transducer is in the range 100 2
94. le Sate loeb ee eho 6 12 6 12 Autocalibration Connections 000 0 eee 6 13 6 13 External Fan AA AA 6 16 6 14 Internal Fan coros roaa a a E EERE eon EEEE een E E EREE G 6 17 6 15 Microprocessor Sensor Interface and Option boards 6 18 6 16 Multiplexer Board 0 6 18 6 17 Multiplexer Board Fuses 00200 6 19 6 18 Terminal Board iracion ee E E ee 6 20 6 19 Mother Board dias ee tales tiga ilaban te Cine ble bao te TAE Mahon Eres tears 6 21 6 20 Zirconia Gas Sensor Module eee eee 6 22 6 21 Pressure Driven Zr Inlet Pipework with restrictor assembly 6 23 6 22 6 23 6 24 6 25 6 26 6 27 6 28 6 29 6 30 6 31 6 32 6 33 6 34 6 35 6 36 6 37 6 38 6 39 6 40 6 41 6 42 6 43 6 2 Flow Driven Zr Inlet Pipework without restrictor 6 25 Zirconia Control Board eis fee sd amd rd esd aNG non wes ead oe we ANG AA 6 26 Zirconia Cell sorcerers BANANA AA 6 29 Purity Paramagnetic Gas Sensor Module 6 30 Purity Paramagnetic Heater Assembly 6 31 Purity Paramagnetic Transducer 0 0000 00 6 31 Control Paramagnetic Gas Sensor Module 6 33 Control Paramagnetic Transducer 00005 6 34 Gfx Gas Sensor Module Assembly anaa 6 36 Gfx Source Replacement 00 0c eee 6 36 Gfx Chopper Motor R
95. libration to verify performance Check that concentration of calibration sample corresponds with concentration specified in auto calibration configuration Perform an automatic ONE CYCLE calibration to clear fault Verify correct operation of autocalibration valves if fitted Perform a leak test to verify cross seat leakages Correct fault in accordance with section 5 2 12 if necessary Correct or replace where necessary and perform instrument calibration to verify performance Verify that there are no leaks in the internal pipe work and that flow meters operate correctly if fitted Correct or replace where necessary and perform instrument calibration to verify performance Verify that there are no blockages in the in the restrictive T assemblies for pressure driven options Correct or replace where necessary and perform instrument calibration to verify performance Refer to section 6 21 for typical restrictor assembly Verify that the instrument exhaust port is not restricted and that the instrument is not being pressurised significantly above ambient pressure Correct or replace where necessary and perform instrument calibration to verify performance Verify continuity of interconnecting wiring within the transducer and from the transducer to the Multiplexer PCB Correct or replace where necessary and re verify instrument performance Check that the cell outputs shown in the instrument diagnostics display match the output vol
96. n auto transformed tapping for auxiliary power this tapping is not used on the Xentra 4100 The auxiliary power tapping is fused via F2 which is mounted on the Motherboard but accessed from the rear of the chassis Each primary winding has an self resetting over temperature cutout which operates at 110 C There are two versions of the transformer one provides power for two gas sensor modules and the other provides power for four gas sensor modules The transformers have one secondary winding per gas sensor module nominally 18 0 18 V ac Gas sensor module power Refer to figure 6 4 The transformer secondary windings are connected to the Motherboard via a connector 13 The secondary windings are then routed on to the Multiplexer board 1 via connector 22 Each secondary winding has two soldered in fuses on the Multiplexer board The secondary windings are then routed to the gas sensor modules via four connectors on the Multiplexer board 2 13 Gas S Multiplexer Moaie TO PCB 04000924 Gas Sensor Module 2 Gas Sensor Module 3 NOT USED n a a Gas Sensor Module 4 Power Inlet gt Switch and Abs Pressurg PL7 Filter Assy Isolating Transformer 4961 1159 or 4961 1166 Diff Pressure Solenoid Valve 1 Solenoid Valve2 Switched Mode Power Supply 4911 6034 External Fan Internal Fan o PL5 O pa m AI W O gt A w gt n n m Ww mp lt O A o o O O
97. n from Mother board 9 d Remove filter cover 6 filter gauze 5 and filter element 4 e Remove four off screws 7 mp Remove finger guard 3 and spacer plate 2 The fan may now be lifted away from the chassis Refitting Use reverse procedure NOTE Ensure that flow direction arrow on the fan body is pointing towards the rear of the chassis 6 16 6 14 Internal fan Refer to figure 6 7 Figure 6 7 Internal fan Removal a Remove cover see section 6 1 b Disconnect fan connector 6 from Motherboard 7 c Remove four off fixing screws 4 d Remove fan spacer plate 1 e Unclip lead from Motherboard and remove fan from chassis Refitting Use reverse procedure NOTE Ensure that arrow on fan is pointing towards rear of chassis 6 17 6 15 Microprocessor Sensor Interface and Option boards 6 16 6 18 CAUTION The microprocessor board is a static sensitive device Failure to implement good standard anti static practices could result in damage Take care to replace option boards and Sensor interface boards in their correct location Any changes of card type recognised by the software will result in erasure of the current set up of analogue outputs NOTE If the microprocessor PCB is replaced then the software of the analyser will need to be re configured as described in section 7 2 If a Gfx module is present in the 4100 then its defini
98. n measured and actual concentration current measured value target value of calibration sample i e a positive number indicates a positive drift Applicable to paramagnetic gas sensors only Table 1 6 contains the an example procedure for displaying the calibration history NOTE The history may include reference to other gas sensor modules Some of these may be of the same type Table 1 6 Displaying paramagnetic purity gas sensor calibration history L MENU to obtain top level menu CALIBRATE SETUP L ENTER ALARMS FAULTS MANUAL CAL AUTO CAL ENTER PASSWORD 0000 CALIBRATE I2 Oxygen 8 LOW CAL HIGH CAL HISTORY CHK L amp H LOW HISTORY HIGH HISTORY l2 OxygenCML0 213 01 15 20 28 118 L ENTER Note that AUTO CAL will only appear when the analyser is configured with the autocalibration option To change the value of a digit L or To change to another digit L or lt When the value shown is correct L ENTER To select desired gas sensor module L gt or then L ENTER if only one module is fitted this section will be omitted L ENTER L ENTER to view Low cal history L ENTER to view High cal history L gt or to view further entries L MEASURE to return to measurement display 1 13 Displaying diagnostics information The signals from gas sensors may be displayed These may be useful in diagnosing any problems which may arise The procedure for displaying diagnostics information is describ
99. n the instrument are not blocked Correct or replace where necessary and re verify instrument performance Verify that the pipe work attached to the instrument vent is not restrictive and resulting in pressurisation of the sample cell Correct or replace where necessary and re verify instrument performance Verify that the transducer is not contaminated particularly with condensed water Correct or replace transducer if necessary and re verify instrument performance Replace transducer and verify that the problem is corrected 5 21 5 3 7 5 4 5 4 1 5 4 2 5 22 Inaccurate pressure compensation Symptoms Incorrect cell pressure indication Analyser output sensitive to ambient pressure changes Drift Flow sensitive results Measurement and Diagnosis a Check that the pressure sensor offset has been correctly calibrated Perform a pressure offset calibration in accordance with the instructions in the Xentra 4100 operators manual and re validate analyser performance b Verify continuity of wiring between the 1166 pressure transmitter PCB and the Multiplexer PCB Correct or replace where necessary and verify instrument performance C By varying the pressure to the pressure sensor check the operation of the pressure sensor and transmitter PCB Correct or replace where necessary and verify instrument performance Pm O Control Transducer Faults Diagnostics measurements Table 5 5 shows a list of the diagnost
100. nal to disable the instrument and measurements during incorrect motor operation The D14 green LED is switched on when the motor is in synchronisation The ICs 8 9 10 11 12 and TR s 2 3 5 and 6 form a switched mode supply for the Infra red source IC10 is a switched mode controller Passive low pass filters added to the voltage and current sense inputs on IC10 are for EMC suppression R82 TR5 and TR6 detect and open circuit failure or a malfunction of the switched mode power supply IC13 sends the fault signal to the MAST connector the event of any errors being signalled IC11 and IC12 perform voltage sensing and programming and the D11 green LED is used to signal a malfunction of the switched mode power supply The switch SW1 is used to change the IR source voltage For the 1210 transducer SW1 is set to position 5 in order to have a source voltage of 2 0 volts The D15 green LED is used to signal that the power supply is on and the D16 green LED is used to signal that the transducer is in working order A malfunction of the switch mode power supply a motor which is not in synchronisation or a problem with power supply from Xentra unit will switch off the D16 green LED The ICs 14 15 16 and 17 provide the digital logic required for the analogue multiplexer from the signal processing PCB IC 14 provides a 16 MHz clock for the EPLD IC16 The synchronisation signal from the optical sensor provides information in respect to the disk posi
101. nect the DVM ve lead to TP3 Vy and adjust RV1 on the detector pre amp PCB 1210 901 until the DVM reading is 1 0v 0 05v Connect the DVM ve lead to TP2 Van and adjust SW1 and RV1 on the signal processing PCB 1210 902 until the DVM reading is 0 0v 0 01v Connect the DVM ve lead to TP4 Vas and check that the DVM reading is equal to the reading at TP3 0 1v Chopper box temperature check d e Allow the transducer to stabilize 30min minimum Measure the chopper box temperature with a thermocouple inserted beneath the insulation this should be 65 C to 75 C 6 51 6 52 Calibration NOTE If a new chopper wheel or a new IR filter has been installed it will be necessary to return the transducer to the factory for linearisation Connect the analyser output to a suitable chart recorder Connect N to the instrument at a flow rate of 1 0 l min Monitor the output and ensure that it is stable lt 1vpm hour before proceeding Perform a manual zero calibration setting the target concentration to Ovpm and accept the reading when stable Connect the span gas to the instrument at a flow rate of 1 0 l min Perform a manual span calibration setting the correct target concentration and accept the reading when stable
102. nfiguration format 223 na hek KAKA PLA LANA reese 7 8 7 1 7 2 NOTES 7 1 SOFTWARE MAINTENANCE Software upgrade installation CAUTION The microprocessor board is a static sensitive device Failure to implement good standard anti static practices could result in damage This section details instructions for performing a software update on an instrument The kit supplied to perform the upgrade will consist of two off EPROM s labelled 04000 6xx yyA and 04000 6xx yyB It is not normally necessary to replace the EEPROM figure 7 1 8 If the EEPROM should require replacement then this will be supplied as part of the upgrade kit Figure 7 1 Microprocessor board 7 3 7 4 Procedure Refer to figure 7 1 a b Remove microprocessor board from instrument chassis using the procedure defined in section 6 15 of this manual Using an IC removal tool or similar suitable device remove the two EPROM S from the PCB 4 5 Insert the two new EPROM s into the PCB The EPROM labelled A should be fitted in position 4 The EPROM labelled B should be fitted in position 5 If a new EEPROM has been supplied as part of the upgrade kit then the existing EEPROM 8 should be removed and replaced in a similar manner It may be necessary to fit the EEPROM before installing the EPROM ss 4 5 to ease installation Check all IC s installed to ensure that none of the pins h
103. ng the wires Lift the PCB free from the chopper box It will still be connected via the transition cable to the house keeping PCB Refer to figure 6 16 e Now remove the chopper box 8 from the base plate 6 by releasing the two anti vibration mount fixings 8 and sliding forward and up Remove the connectors from the house keeping PCB 10 and release the six PCB fixings 9 Remove the PCB from the base plate and ease away the chopper motor PCB and cable Refitting a Reassemble the transducer using the new PCB as above in reverse order Layout the cables beneath the house keeping PCB to aid re assembly Refer to figure 6 17 b The new thermal fuse 59 and lead insulators should be fixed to the PCB before assembly 6 39 c The power transistor 55 is supplied loose and should be fixed to the chopper box using the correct assembly of the insulating kit before soldering the leads to the PCB CAUTION Ensure that the correct cables are fitted to the correct sockets before applying power see figure 6 20 d Replace the chopper box scrubber see section 6 31 b e Replace the transducer into the 4100 chassis in the same position see section 6 30 f Setup and calibrate according to section 6 41 Gfx house keeping PCB assembly Removal Refer to figure 6 16 Remove the transducer from the 4100 chassis see section 6 30 Remove the two cell anti vibration fixings and mounts 12 Remove all connecting c
104. nting the concentration measured The engineering units field is a user defined 3 character message identifying the units of measurement The engineering units field is a message only Changing the engineering units message has no effect on the displayed value The user defined message UDM field is a 6 character field to represent the process variable name or tag number The Xentra display may be returned to measurement display at any time by pressing the MEASURE key see figure 1 4 If no user key presses are input then the Xentra returns to the measurement display after a one minute time out This time out is extended to 20 minutes during the calibration options When first powered up the display will show a sequence of power up messages before returning to the measurement display If the user does not wish to see the power up messages then these can be disabled by pressing the measure key during the SYSTEM OK message The warming up icon see figure 1 5 will also be displayed until all gas sensor modules are at their respective operating temperatures This may take up to 3 minutes for zirconia gas sensor modules and 6 hours for paramagnetic gas sensor modules The reading of any zirconia gas sensor module may be replaced by a row of stars during the warming up period Icons located at the bottom of the measurement display indicate the status of the instrument see figure 1 5 These icons show that the
105. oosen the three PCB fixing screws 52 and carefully withdraw the PCB assembly 63 taking care not to allow the spacers 53 to fall Figure 6 19 1210 Gfx detector assembly Refitting a Remove the screws and spacers from the old PCB and assemble same onto the new PCB Ensure that the o ring 54 is in position inside the light pipe 19 b Holding the screw heads in place with three fingers offer the assembly up to the light pipe 19 in the correct orientation and push home Complete the re assembly as above in the reverse order Fit a new detector scrubber Fit a new chopper box scrubber if the cell assembly was moved see section 6 31 b QO o xe ad 6 45 6 38 6 46 CAUTION The detector light pipe 19 is a sealed enclosure Once opened a new scrubber must be fitted e Replace the transducer into the 4100 chassis in the same position see section 6 30 f Setup and calibrate according to section 6 41 Gfx chopper box PCB assembly Removal Refer to figure 6 17 Remove the transducer from the 4100 chassis see section 6 30 Remove the cell assembly see 6 32 Remove the chopper wheel see 6 32 Remove the power transistor fixing screw 55 Unsolder the two heater 56 and the thermistor 57 connections on the chopper box PCB 45 Remove the four PCB fixings 58 and carefully raise the PCB whilst holding the chopper motor plug from beneath to prevent straini
106. outside of acceptable limits after three calibration attempts a fault is indicated The A D has digital registers and may occasionally be corrupted by electrical interference However this should be self correcting unless the interference is persistent Solenoid valve drives The four control lines are latched into a D type latch on the Multiplexer board two of these latched lines are used to drive the solenoid valves via transistors Microprocessor board Refer to figure 7 1 The Microprocessor PCB 1 also figure 6 4 6 runs software specific to the gas sensor module population and interfaces to the following via the microprocessor bus Display Keypad Sensor interface board and option boards The software is contained in two EPROMS 4 5 which are known as Firmware once programmed The microprocessor board also contains RAM 6 7 for temporary data storage EEPROM 8 for indefinite storage of calibration and set up information such as analogue output ranging and a real time calendar clock which continues to keep time during power down by drawing power from a super capacitor The super capacitor will power the calendar clock for between 2 days and 2 weeks Note If the analyser is powered up with either its sensor interface board or any option boards removed any set up information for those boards will be lost The green LED at the top of the microprocessor board indicates that the microprocessor is not being reset when illuminat
107. ows The appearance of this message is entirely normal as there is no longer any useable data stored in the EEPROM To re activate the instrument the system will need to be re configured by re entering the special configuration menu by re entering the encrypted key sequence section 7 2 1 the special password 7 2 1b is not required for this operation The system will then prompt the user for an S number with which to effect configuration The S number of the system is an alphanumeric code 24 characters in all that defines the explicit configuration This is detailed in the 4100 Technical Data Sheet Available from your local Servomex company representative or agent The original S number for each instrument is recorded on the software configuration label on the base of the instrument The important entries necessary to configure the software are given in figure 7 3 None of the entries other than those referenced in figure 7 3 have any effect on software configuration and are only present as a record of the instrument configuration When the S number has been entered the system will briefly respond INITIALISATION IN PROGRESS before dropping into the normal start up sequence 7 7 7 3 7 34 7 3 2 7 8 4102 B101011230XX11100011 Auto calibration Transducer population Model issue number Instrument type 4102 or 4104 Figure 7 3 S Number Configuration Format Definitive Calibration of Gfx The menu struc
108. perature above 600 C it will conduct oxygen ions The oxygen ion conductivity increases exponentially with temperature The sensor consists of a disc of yttria stabilised zirconia mounted in a tube of the same material The faces of the disc are coated with platinum and the assembly is mounted in a small temperature controlled tubular oven 3 11 3 3 2 3 12 When the two sides of the disc are exposed to gases containing oxygen a concentration cell is formed and an electrical output proportional to the logarithm of the ratio of the oxygen concentrations on each side of the disc is obtained When the concentration is the same on both sides of the disc the logarithm of the ratio is 0 The fact that the oxygen content of air is very constant at 20 95 makes it convenient to use air as the reference gas which is applied to one side of the disc while the sample is applied to the other side The Electronics Functional Destribution The Board provides the following two key areas of functionality Cell temperature control Cell output amplification Operation of these areas of the circuit are described in more detail below Cell Temperature Control The Board provides all of the circuitry necessary to mantain the zirconia cell at its correct operating temperature Heater power to the cell is derived from the AC MAST power connector and is switched under closed loop control The circuit incorporates a soft start feature to reduce th
109. pipe 5 This concentrates the energy onto a pyrolytic infra red detector 6 This measures the intensity of the IR beam The IR radiation that had passed through the nitrogen filter is significantly attenuated when it passes through the sample gas containing CO The radiation that had passed through the CO filter is not significantly affected by the sample gas containing CO because most of the energy at wavelengths characteristic to CO were already removed by the gas filled filter Sample gases containing CO or other IR absorbers attenuate the signal with the nitrogen and CO filled filters equally Hence they have little effect on the 3 7 3 2 2 3 8 measurement Changes in source intensity or contamination of the sample cell also effect the signals with the nitrogen and CO filled filters equally and again have little effect on the measurement The value obtained by rationing the difference between the nitrogen and gas signal with the gas signal is related to the CO gas concentration Any changes which equally affect both nitrogen and CO signals will be cancelled by this design The electronics The Gfx 1210 consists of four main electronic assemblies The Infra Red Detector Pre amp PCB 01210901 Refer to circuit diagram 01210 101 The Infra Red Detector Pre amp PCB translates IR radiation into an analogue voltage which can be further processed in order to extract the useful information IC3 a pyro electric infra red P I
110. place where necessary and verify performance b Verify that there are no leaks in the internal pipe work and that flow meters operate correctly if fitted Correct or replace where necessary and perform instrument calibration to verify performance C Verify that there are no leaks in the pipework to other transducers within the xentra chassis or even other analysers that is causing the oxygen level used as a reference to the zirconia cell to be enriched or depleted d Verify that there are no blockages in the in the restrictive T assemblies for pressure driven options Refer to section 6 21 Correct or replace where necessary and perform instrument calibration to verify performance e Verify that the instrument exhaust port is not restricted and that the instrument is not being pressurised above ambient pressure Correct or replace where necessary and perform instrument calibration to verify performance f Perform the transducer performance checks listed in section 5 5 3 5 5 5 Stability faults Symptoms Noisy reading Reading drifts 5 31 5 5 6 5 32 Instrument requires frequent re calibration Measurements and Diagnosis a Verify that the sample inlet pressure or flow is within the required range For pressure driven options this is 5psig 3psig 35kPag 21kPag For flow driven options this is 200 to 550 ml min Correct or replace where necessary and re verify instrument performance b Perform a le
111. procedure NOTE Ensure that the three motherboard tongues 12 are engaged in the front card frame Ensure that protective earth connections are secure 6 21 6 20 Zirconia gas sensor module Refer to figure 6 10 Figure 6 10 Zirconia gas sensor module WARNING The surface of some components within the zirconia gas sensor module assembly are hot Switch off the electrical power and allow 10 minutes for the zirconia cell to cool before servicing module Removal a Remove cover see section 6 1 b Disconnect signal cable 21 c Loosen two off Zirconia cell housing 2 fixing screws 1 d Slide zirconia cell housing side ways and lift to remove The zirconia cell 6 has two flats for spanners 5 24 one at each end D 6 22 Anchor zirconia cell using spanner flat 24 and undo nut 23 CAUTION If the zirconia cell is not anchored with the correct spanner flat the cell will be destroyed f Loosen four off gas sensor module fixing nuts 16 9 Slide zirconia gas sensor module mounting bracket 18 sideways and lift to remove Rest zirconia gas sensor module on front card frame h Disconnect power cable 22 Refitting Use reverse procedure NOTE When refitting zirconia cell sample connector nut 23 use zirconia cell spanner flat 24 to anchor zirconia cell 6 This union must be leak tight Leaks will cause a high oxygen reading Refer to the Quic
112. r modules from particulate contamination C An Autocalibration facility to allow the transducers to be calibrated without user intervention C Additional signal output cards to extend the number of analogue outputs and relay outputs available to the user A full technical specification for the 4100 Gas Purity Analyser is presented in both the Technical Data Sheet and the QuickStart manual available from your local Servomex Company agent or representative Location of components Figure 1 1 identifies the location of the key features of the Xentra 4100 Gas Purity Analyser Introduction to the Xentra user interface The Xentra user interface consists of a keypad with nine keys and a large edge lit LCD display see Figure 1 1 During normal use of the instrument the LCD screen will display either the default measurement display or a menu based screen editor display Toggling between the measurement display and the menu based editor is via the keypad User input to the menu based screen editor is also via the keypad The Xentra measurement display The measurement display is the default display that is presented to the user of the Xentra 4100 The display can be user configured to show the gas concentrations measured by the gas sensor modules fitted The status of the instrument plus the occurrence of an alarm or fault active are also displayed on the measurement display via icons positioned at the bottom of the screen The contents of
113. re correctly configured and enabled within the instrument software Correct where necessary and re validate instrument performance b Check that interconnecting wiring is correctly installed within the screw terminal block within the external two part connectors This is conveniently accomplished by removing the connector and checking operation at the connector pins Correct where necessary and re validate instrument performance 5 9 5 2 7 5 10 Ensure that the signal interface board optional output boards and associated terminal boards are correctly located within their connectors on the mother board Correct where necessary and re validate instrument performance If more than one output board is fitted and all outputs are not working then replace the microprocessor PCB and re validate instrument performance If there is only one output board the Sensor Interface PCB or the fault lies within the first output board then replace the Sensor Interface PCB and or its associated terminal PCB and re validate instrument performance If the fault is located on one of the remaining optional output boards then replace the faulty output PCB and or its associated terminal board and re validate instrument performance Replace the microprocessor PCB and re validate instrument performance Note Replacing the microprocessor PCB will require reconfiguration of the analyser Refer to section 7 2 Check electrical continuity between the output
114. refitting failure to do this will result in fracture of the flow tube NOTE The sample and calibration gases used with the instrument may be toxic or asphyxiant Ensure that gases are turned off and the instrument is flushed with inert gas before opening the instrument le system to air Removal Remove cover See section 6 1 b Remove flow tube cover fixing screws 3 one per flow tube cover The flow tube covers 4 5 may then be removed by bringing top edge forwards and lifting c Loosen top flow tube end block 7 8 fixing screws 6 two per end block The end blocks may now be lifted directly upwards clear of the flow tubes 9 10 with the sample tubing still attached d The flow tubes may now be lifted directly upwards a slight twisting motion may be used to help release the tubes as they are lifted e The end block spigot o rings on the end block spigots should only require removal if they need to be replaced In this case the o rings may be prised off using a screwdriver and discarded Refitting Use reverse procedure Flow tube o rings may be lubricated with clean water sparingly applied with a brush Ensure that flow tube covers are replaced in correct positions ie Sample and Bypass labels appear in correct positions 6 7 Flow tube end blocks Refer to figure 6 2 6 9 6 8 6 10 NOTE Take care to keep the end block spigot and flow tube concentric when removing and refitting fa
115. ressurisation of the sample cell Correct or replace where necessary and re verify instrument performance e Replace transducer and verify that the problem is corrected 5 6 1210 Gfx Transducer Faults 5 6 1 Diagnostics measurements Table 5 8 shows a list of the diagnostic signals available for the Gfx1210 transducer Table 5 8 Diagnostic signals for the Gfx 1210 transducer Diagnostic Description Typical level Range DIF SIG Difference signal 0 25 to 1 31 between the Gas V and N filled filters GAS SIG Signal level for the 0 5 to 1 31 V Gas filled filter N2 SIG Signal level for the 0 5 to 1 31 V N filled filter SAMPLE Sample 0 to 50 C TEMP temperature CHOPPER Chopper box 60 to 80 C TEMP temperature 5 33 5 6 2 Fault messages Table 5 9 shows a list of the indicated fault conditions for the Gfx 1210 transducer Table 5 9 Fault messages for the Gfx1210 transducer Fault indicated Possible causes Recommended action 5 6 3 Transducer faults NOT RESPONDING CHOP TEMP LOW or CHOP TEMP HIGH LO V C OUTSIDE TOL or HI V C OUTSIDE TOL LO V C OUTSIDE RANGE or HI V C OUTSIDE RANGE LO CAL OUTSIDE LIMITS or HI CAL OUTSIDE LIMITS TRANSDUCER Faulty component See section 5 6 3 Faulty component See section 5 6 3 User set low or high See section 5 6 4 calibration tolerance has been exceeded during autocalibration The gas Respecify
116. rminal block fitted to connector PL5 pins 13 and 14 Correct where necessary and re validate instrument performance Replace the Sensor Interface PCB and re validate the instrument performance Replace the microprocessor PCB and re validate instrument performance Note Replacing the microprocessor PCB will require reconfiguration of the analyser Refer to section 7 2 Replace the motherboard PCB and re validate instrument performance 5 2 10 No response to auto cal initiate input Symptoms Autocalibration not activated by closure of external auto cal initiate contacts Measurements and Diagnosis a Check that the autocalibration configuration is correctly configured and enabled within the instrument software Check that the S number feature 11 within the instrument ID is set to 1 or 2 Correct where necessary and re validate instrument performance Check that connecting wiring is correctly installed to pins within the screw terminal block fitted to connector PL5 pins 11 and 12 Manually short circuit pins 11 and 12 for at least 5 seconds while the instrument is in the measurement display to initiate an autocalibration Correct where necessary and re validate instrument performance Replace the Sensor Interface PCB and re validate the instrument performance Replace the microprocessor PCB and re validate instrument performance Note Replacing the microprocessor PCB will require reconfiguration of the analyser Refer
117. rticular attention to flow meter leakages if these are fitted Correct or replace where necessary and re verify instrument performance Verify that the restrictive T assembly for pressure driven option within the instrument are not blocked Correct or replace where necessary and re verify instrument performance Verify that the sample pipe work attached to the instrument vent is not restrictive and resulting in excessive pressurisation of the sample cell Correct or replace where necessary and re verify instrument performance Verify that the transducer is not contaminated particularly with condensed water Clean the optical cell and or replace the optical windows and mirrors if necessary and re verify instrument performance 5 39 NOTES 5 40 SECTION 6 PARTS REPLACEMENT PROCEDURES LIST OF CONTENTS Section Page 6 1 OOVER AA NADAGANAN DAD E PAN NAA 6 5 6 2 Fascia Removal o e223 AA is DANG DA es ee 6 6 6 3 Keypad PCB and Rubber Mat 22 6 7 6 4 DISPIAY 255 Aha RAE mA 343232525453 BA NG de Dad nd be Ded oe bees 6 7 6 5 Keypad Ribbon Cable 0 22 eee 6 8 6 6 FIOW TUDES ocho ice a ee hs Wa hs ahs hs ni ha hs ata he ene as 6 9 6 7 Flow Tube End Blocks cece ees 6 9 6 8 Sample Filter Housing 00 eee eee 6 10 6 9 Switched Mode Power Supply eee eee 6 11 6 10 Transtormer pp PAA PARTI AP Mee a isa ies hie eee 6 11 6 11 Power Connector 4 6de4s dete eUeds e
118. s for the Pm O purity transducer Fault message Fault history Remedial action message CELL TEMP CELL T LO Check fuses F1 to F8 on multiplexer LOW PCB Check replace paramagnetic cell heater assembly or transducer CELL TEMP CELL T HI Check replace paramagnetic heater HIGH assembly and or paramagnetic transducer CELL VOLTS CELL V LO Check replace paramagnetic LOW transducer HIGH PRESSURE CELL P LO Check voltage TP03 with respect LOW to TP0O1 on multiplexer PCB Check replace pressure transducer assembly Figure 6 14 15 CELL VOLTS CELL V HI PRESSURE CELL P HI Check sample outlet is not HIGH obstructed Check replace pressure transducer assembly figure 6 14 15 LOW CAL LO TOL Check USER SET limits Check OUTSIDE TOL calibration gases Check operation HIGH CAL HITOL of auto calibration solenoid valves OUTSIDE TOL Attempt manual calibration check HIGH CAL HI RANGE OUTSIDE RANGE SAMPLE LOW FLOW Check sample gas pressures and FLOW LOW flow Check sample needle valves Check filter and auto calibration solenoid valves LOW CAL LO RANGE OUTSIDE RANGE 5 3 3 Transducer faults Symptoms No response from transducer with changing gas composition Transducer producing invalid results Measurements and Diagnosis a Verify continuity of interconnecting wiring between the measurement cell and the house keeping PCB and between the transducer and the Multiplexer PCB Correct or
119. s not respond to span gas If this is the case replace the chopper wheel If you suspect a slow leak from the gas filter perform a ZERO CAL then expose the instrument to a certified span gas If the instrument reads less than 50 of the span gas then replace the chopper wheel see section 6 33 and return to Servomex for investigation Excess noise can be caused by a defective chopper motor If the motor has difficulty starting or is audibly noisy then replace it see section 6 32 and return the motor to Servomex for investigation In very rare instances the detector may be faulty Connect a scope to TP1 wrt TP5 on the signal processing PCB 1210 902 The trace should be stable and look like the trace shown in figure 6 21 If the signal is very noisy then replace the detector PCB see section 6 37 5 6 6 Flow faults Symptoms Slow instrument response Inaccurate instrument results Flow sensitive results Measurement and Diagnosis a Verify that the sample flow rate through the transducer is in the range 500 2500 ml min Verify that any flow problems encountered are not produced by any sample conditioning system used prior to sample entry into the instrument Particular attention should be made to knock out pots sample pumps chillers and filters Correct or replace where necessary and re verify instrument performance By performing a leak test verify that the internal pipe work within the instrument is leak tight Pay pa
120. s the sample the output increases with decreasing oxygen Samples with more oxygen than air 20 95 oxygen will give a negative cell output E E 0 021543 T Ln 20 95 oxygen in sample E Cell output mV E Cell offset mV T Cell temperature K E may be determined by using air as the sample Note that the cell temperature is display in C whereas the Nernst equation required K To convert to K add 273 to the C reading Sample calculation assuming the sample gas is 0 3 oxygen and the cell is running at 575 C E E 0 021543 575 273 Ln 20 95 0 3 E 77 57 mV A XXX fault is indicated if the zirconia cell output lies outside of the range 50 to 500mV 5 5 2 5 5 3 Fault messages Table 5 8 shows a list of the indicated fault conditions for the zirconia transducer assemblies Table 5 8 Fault messages for the zirconia transducer Fault message Fault history Remedial action message CELL TEMP CELL T LO Check cell thermocouple LOW connections and polarity to PCB Check fuses F1 to F8 on multiplexer PCB Check links on PCB CELL TEMP CELL T HI Check thermocouple connections HIGH Check links on PCB Check replace zirconia cell Check cell electrical connections LOW Check links on PCB Check replace PCB Check replace zirconia cell CELL EMF CELL E HI HIGH Transducer faults Symptoms CELL TEMP LOW fault reported CELL TEMP HIGH fault reported CELL EMF LO
121. sert it into the cavity Replace the blanking plug and tighten making sure that the paper scrubber bag is not damaged Replace the transducer into the 4100 chassis in the same position see section 6 30 Setup and calibrate transducer according to the procedure in section 6 41 CAUTION The chopper box and light pipe see figure 6 16 3 19 are sealed enclosures Once opened a new scrubber must be fitted 6 37 Figure 6 17 Gfx 1210 chopper box assembly 6 32 Gfx chopper motor replacement Removal Referring to figure 6 16 Remove the Gfx transducer from the 4100 chassis see section 6 30 Cell assembly removal Remove the insulation retaining clip 2 and insulation 1 from the chopper box 3 Remove the detector ribbon cable and earth wires 23 from the detector box 22 WARNING Hot surfaces are present on the chopper box and IR source see figure 6 17 3 31 Remove the cell assembly by removing screws 15 and cell clamps 16 then remove the three cell flange chopper box lid fixings 4 Carefully withdraw the cell assembly and remove the CaF window 17 and o rings 18 from the chopper box lid and cell end Refer to figure 6 17 The IR filter 62 is now exposed NOTE Do not touch the IR filter 62 with bare fin Chopper wheel removal Remove the earth wire 36 Remove the three signal processing PCB shielding box retaining screws 37 and remove
122. side in the Xentra chassis The Xentra chassis provides power gas connections and other support functions to the gas sensor modules and receives their outputs from which it calculates sample gas concentrations The calculated gas concentrations then may be displayed on the LCD display screen directed to the analogue outputs and or directed to the serial RS232 output The Xentra chassis also supports two external analogue input signals These inputs may be used to combine the data from external transducers with the internal transducer data The data from the external inputs may be displayed on the screen output to the analogue outputs and or output via the serial RS232 output The Xentra 4100 is designed for use in modern industrial and laboratory environments with emphasis on durable rugged construction low cost of ownership reliable performance simple operation and ease of service The analyser is controlled using an on board microprocessor which gives the flexibility to configure the analyser to suit a wide range of applications 1 3 1 3 1 4 1 4 1 1 4 The Xentra is operated via simple keypad controls mounted on the front facia of the analyser Adjacent to the keypad is a large Liquid crystal display LCD on which are displayed measurement values alarms and other data A number of optional features are available for the Xentra 4100 These include the following C A sample filter to protect the paramagnetic gas senso
123. sistance tests now show a short circuit then determine whether the short lies on the switched mode power supply the transformer or the mains cable form including IEC connector This is accomplished by disconnecting each in turn until the short circuit is removed If the mains power input resistance checks still show an open circuit then check the continuity through the mains power connector mains cable form Mother board and transformer Replace any faulty components located in order to achieve the correct mains input resistance Transformer secondary short circuit Measurements and diagnosis Power up the analyser and check that the analyser is now operational If either fuse has blown then disconnect the transformer secondaries and try again If the instrument power up is now OK then trace the short circuit 5 5 5 6 24V rail shorted overloaded Measurements and diagnosis Check the 5V and 24V rail supplies using the test points on the multiplexer PCB The rail voltages should be as follows TPO8 wrt TPO1 24Vdc 2V TPO5 wrt TPO1 5 05Vdc 0 25V If the 24V rail is overloaded or short circuit then all the supplies will be shut down If this voltage is outside of this range then replace the switched mode power supply No power supply to the invertor PCB Measurements and diagnosis Remove the instrument fascia and check the voltage at the input to the invertor PCB pin 2 wrt pin 1 24Vdc 2V If this voltage is not pr
124. sure driven option has been specifically designed to maintain optimum sample flowrate for an inlet pressure of 5psig 3psig 85kPag 21kPag The sample system operates by restricting the sample flow and redirecting excess sample down a bypass route to the outlet The system will accommodate minor changes in inlet pressure but a stable inlet pressure is recommended 2 1 13 Gas sensor modules Zirconia example shown in Figure 6 10 The gas sensor modules mount to the base of the chassis using studs fixed into the chassis base 16 The studs are fitted with nuts with integral locking washers The gas sensor modules are provided with slots so that the nuts do not need to be removed from the mounting studs Once the nuts are loosened the gas sensor module may slide sideways then upwards for removal 2 1 14 Maintenance of EMC performance Refer to figure 6 3 To ensure that EMC performance is maintained all cover screws should be refitted and tightened The conductive gaskets 1 along the front edge of the chassis 6 and those on the fascia should also be fitted and replaced where necessary 2 7 SAMPLE OUTLET SAMPLE sample FLOWMETER Ss qT y T OPTIONAL SAMPLE FLOWMETER INLET 00703 OR 00704 CELL Figure 2 1 Typical schematic for flow driven Zr oxygen Trace sample system SAMPLE OUTLET BYPAS FLOWMETEI
125. t lt and then presses the ENTER key When entering numeric information or text the left and right arrow keys lt are used to move between characters or digits and the up and down arrow keys gt are used to change each character or digit Reverse video is used to indicate the active WORD character or digit position Enter key The user presses the ENTER key to indicate that the indicated menu selection is to be actioned or to indicate completion of text or numerical input If when inputting text or numerical data the key press is ignored then this is because the data entered is invalid otherwise the data will be saved The Xentra screen icons The space at the bottom of the measurement display is reserved for status icons The screen icons that may be displayed are shown in figure 1 5 AUTO ALARM WARM FAULT CAL LIF Figure 1 5 Xentra status Icons The function of these icons is as follows Autocal icon This icon is displayed when an instrument auto calibration is in progress Alarm icon This icon is displayed if any of the user defined alarm levels are triggered If this icon is displayed then the nature of the alarm may be found from the user interface see section 1 8 Displaying alarms present 1 4 4 Warm Up icon This icon is displayed if any of the transducers fitted inside of the Xentra are operating at a temperature less than their normal operating temperature band This is normally displayed
126. tage given from the transducer Fault is likely to be either the Sensor Interface PCB or the Multiplexer PCB Identify and replace faulty PCB where necessary and re verify performance 5 37 5 6 5 Stability faults 5 38 Symptoms Excessive measurement noise Excessive instrument drift Low instrument sensitivity Poor instrument accuracy Measurement and Diagnosis a Measure the optical throughput of the transducer to establish any contamination of windows cells and or mirrors To do this look at the value of VN2 in the diagnostics menu During factory calibration this voltage is set to 1 00v any loss of energy throughput will reduce this reading If the value is less than 0 75v then check the following The source voltage setting is 2 0v position 5 on SW1 on 1210 903 The detector is at the correct position using the correct spacers See section 6 37 The optical components are not contaminated or damaged see sections 6 34 6 35 6 36 An exhausted scrubber will cause drift usually correlated to changes in ambient temperature If this is observed check for leaks in the chopper box and detector enclosures and replace the appropriate scrubber See sections 6 32 6 37 Excessive continual positive zero drift associated with a decrease in instrument sensitivity is an indication of gas filter leakage If a gas filter fails it usually does so rapidly giving an instrument with a large positive offset which doe
127. the fascia Refitting a Ensure that keypad rubber matis located over five lugs in fascia moulding 28 b Fit Keypad PCB over five lugs in fascia moulding 28 c Ensure that Keypad PCB fixing screw spacer is present in bottom right fixing position 27 d Use reverse procedure from here NOTE Avoid touching the gold platted contact areas on the keypad PCB or the contact pills in the rubber mat Display Refer to figure 6 2 NOTE Avoid touching the liquid crystal at the front of the display and the inner surface of the window 6 7 Removal a Remove fascia see section 6 2 b Remove display connectors 18 19 c Remove four display fixing screws 23 d The display 24 may now be lifted away from the fascia Refitting Use reverse procedure 6 5 Keypad ribbon cable Refer to figure 6 3 Removal a Remove fascia see section 6 2 b Disconnect Keypad ribbon cable 2 from Motherboard 4 c Prise off two ribbon cable clamps 9 and remove ribbon cable Refitting a Peel off adhesive backing from ribbon cable clamps and position in place of original clamps b Connect Keypad ribbon cable to Motherboard and feed other end through grommet 7 c Dress ribbon cable 2 along side of chassis and fix to two ribbon cable clamps 9 Figure 6 3 Keypad ribbon cable 6 8 6 6 Flow tubes Refer to figure 6 2 NOTE Take care to keep the end block spigot and flow tube concentric when removing and
128. the shielding box 38 Remove the three PCB retaining screws 39 and pull the PCB 64 forward to allow access to the chopper box lid Remove the four chopper box lid retaining screws 40 and carefully remove the chopper box lid 61 Remove the three chopper wheel retaining screws 41 and carefully remove the chopper wheel 42 by aligning the large slot with the optical pick up Do not touch the surfaces of the gas filters with fingers CAUTION The chopper wheel 42 should be treated with care as the gas filters can be broken by rough handling Chopper motor removal Remove the two motor mounting fixings 43 6 39 6 33 6 40 and withdraw the motor 60 forward easing the motor plug from the PCB 45 connector Remove the two screws 44 to separate the motor mounting plate 46 from the motor Replacement a The new motor is installed by reversing the procedure described above Inspect the o rings and replace where necessary b Install a new chopper box scrubber see section 6 31 b C Replace the transducer into the 4100 chassis in the same position see section 6 30 d Setup and calibrate transducer according to section 6 41 Gfx chopper wheel replacement Refer to figure 6 16 Removal a Remove the transducer from the 4100 chassis see section 6 30 b Remove the cell assembly see section 6 32 c Remove the chopper wheel see section 6 32 Replacement a The new chopper wheel may be inst
129. then be displayed EDIT ID DEL HIST CAL TXD RECONFIG The functions of the menu entries are as follows EDIT ID This enables the user to change the serial number and order number of the instrument This should only be performed during factory calibration or if the EEPROM 8 or the microprocessor PCB 1 containing a new EEPROM is changed In these cases the displays should be returned to their original values DEL HIST This deletes the contents of all the history buffers on the instrument This includes faults alarms and calibration histories This should only be performed during factory calibration CAL TXD This option is only required on the xentra 4100 if a Gfx transducer is fitted and either the EEPROM 8 or the microprocessor PCB 1 containing a new EEPROM is changed 7 2 5 RECONFIGURE NOTE This totally reformats the configuration of the instrument On selection of this option all calibration and configuration information will be deleted On selection of this option the software will ask twice that the user confirms his intention totally to erase the current system configuration When selected the screen will go blank for some seconds before the following message is displayed INCOMPATIBLE DATA FORMAT CONTACT LOCAL SERVOMEX SERVICE If a new EEPROM or a new microprocessor PCB with a new EEPROM is fitted then this message will also be displayed and the instrument will have to be re configured as foll
130. tion Inside the EPLD this signal is processed in order to implement the address lines At and AO and an enable signal for the analogue multiplexer IC15 and IC16 are used as frequency dividers IC18 a serial EEPROM circuit is programmed by the Xentra unit and stores the liniarisation information required for the calibration of the 1210 transducer The Chopper Box PCB 01210904 Refer to circuit diagram 01210 104 The Chopper Box PCB provides the interface between the motor and the housekeeping board The optical sensor which generates the synchronisation signals from the chopper wheel is also located on this board A slotted optical sensor is used to detect slots around an interrupter disc The signal provided by the optical sensor is used to synchronise the analogue multiplexer The board also includes the motor interface and a AD590 temperature sensor 3 3 Zirconia transducer module 3 3 1 Principal of operation FLEXIBLE WELDED ZIRCONIA CELL DIAPHRAGM JUNCTION THERMOCOUPLE DISC THERMOCOUPLE HEATER SAMPLE SIDE REFERENCE SIDE iy Naa LLL ST LLLAB tS Co a KKK aS NS AT IN gt 5 KA x g Ng K EZAZ U ase LE LE LL Al GAS CERAMIC METAL ALUMINA CELL POROUS CERAMIC CERAMIC COUPLING GLASS SEAL TUBE OUTPUT ELECTRODES GLASS SEAL WIRES Figure 3 3 Zirconia Cell Cross Section The Servomex R zirconia sensor Figure 6 3 is manufactured using yttria stabilised zirconia When this material is heated to a tem
131. tion for the subsequent sections 3 Gas Sensor Module Technology Overview Provides an overview of the technology used in the 4100 Gas Purity Analyser 4 Spares List Lists the available spares No other spares are available 5 Fault Finding Describes fault finding procedures 6 Parts Replacement Procedures Described procedures to replace and test parts 7 Software Maintenance Describes software maintenance procedures 8 Engineering Drawings Contains a list of drawings and schematics attached to this manual NOTES SECTION 1 INTRODUCTION LIST OF CONTENTS Section Page 1 1 Introduction s863 ka an eee eis ee a a NAE a 1 3 1 2 General Description 00 022 1 3 1 3 Location of Components 2 1 4 1 4 Introduction to the Xentra User Interface 1 4 1 5 Transducer Site Numbering System 2 45 1 12 1 6 Output Numbering System 0c eee eee 1 12 1 7 Transducer Full Scale Deflection 2 24 1 13 1 8 Displaying Alarms Present 1 14 1 9 Displaying Faults Present 0 eee eee 1 14 1 10 Displaying Alarm History 2 000000 1 15 1 11 Displaying Fault History 22 0000 1 15 1 12 Displaying Calibration History aa aaa aaaea 1 16 1 13 Displaying Diagnostics Information 1 17 LIST OF FIGURES Figure Page 1 1 Key features of the Xentra 5 3 Nad Gab KAT KAG DAP
132. tive calibration data will need to be transferred from the Gfx to the new microprocessor PCB using the DOWNLOAD feature as described in section 7 3 2 a Remove cover see section 6 1 b Touch bare metal on chassis to discharge any static electricity c Slide board up out of card guide d Store board in anti static bag Refitting a Touch bare metal on chassis to discharge any static electricity b Slide board into card guides and push firmly into Motherboard c Refit cover Multiplexer board Removal Refer to figure 6 4 Remove cover see section 6 1 Touch bare metal on chassis to discharge any static electricity Slide Multiplexer board 1 up out of card guides with gas sensor module signal cables 23 power cables 24 Lay Multiplexer on top of front card frame figure 6 9 10 Remove signal cables 23 and power cables 24 Refitting Use reverse procedure Dress signal and power cables away from hot surfaces such as the Zirconia gas sensor module cell housing figure 6 10 2 NOTE When refitting gas sensor module signal cables to Multiplexer board it is important that they are located in the correct connector see figure 6 4 6 17 Multiplexer board fuses Refer to figure 6 8 maa ASSY No _ 040009XX Figure 6 8 Multiplexer board fuses Removal a Remove Multiplexer board see section 6 16 b Determine which fuses 2 are open circuit and replace 6 19 6 18 6 20 R
133. to section 7 2 Replace the motherboard PCB and re validate instrument performance 5 2 11 Analyser does not keep correct time date Symptoms Time and or date requires frequent correction or does not work Measurements and Diagnosis a b Check that internal clock has been correctly set and the instrument has not been powered down for period exceeding two days Replace microprocessor PCB and re validate instrument performance Note Replacing the microprocessor PCB will require reconfiguration of the analyser Refer to section 7 2 5 13 5 2 12 Calibration gases are not introduced via solenoid valves Symptoms Autocalibration failure Autocalibration valves do not operate Measurements and Diagnosis a b Check that calibration gases are correctly attached to inlet ports Manually initiate an instrument autocalibration and listen for an audible click as the valve actuator operates If a click is heard then inspect the manifold block and valve seals for contamination Correct and re validate instrument operation If an audible click is not heard unplug the solenoid valves from connector PL22 and PL23 on the motherboard and verify that the 24VDC operating voltage is present while each valve is being activated If the 24VDC supply is present then the solenoid valve is faulty and should be replaced Ensure that the connectors are correctly replaced onto PL22 and PL23 as indicated by the motherboard markings The 2
134. toms associated with the Xentra 4000 core chassis assembly rather than the individual transducers fitted within it The faults are categorised by the observed symptoms Fault messages Table 5 1 lists the fault messages that are generated by the instrument regarding the core chassis assembly These are stored within the fault history log see also section 1 9 Table 5 1 Chassis fault messages Fault Possible Remedial action message causes BAD Reference Check replace sensor REFERENCE voltage interface PCB and or incorrect multiplexer PCB 5 3 5 2 2 Display not illuminated 5 4 SYMPTOM CHECKS CAUSES DISPLAY NOT CHECK MICROPROCESSOR MAINS POWER INPUT SHORT OR ILLUMINATED BOARD GREEN LED OPEN CIRCUIT TRANSFORMER SECONDARY SHORT CIRCUIT GREEN LED OFF SWITCHED MODE PSU 24V OUTPUT EITHER SHORT CIRCUIT OR OVERLOAD SWITCHED MODE PSU FAULTY NO INVERTOR SUPPLY INVERTOR FAULTY GREEN LED ON BACKLIGHT LAMP FAULTY Figure 5 1 Display not illuminated fault tree Figure 5 1 shows a tree of possible fault causes that would result in the display being blank The display lamp runs off the 24V supply from the switched mode power supply and the Microprocessor board runs off the 5V supply Validity of the supply voltages is assessed by the test points located on the multiplexer PCB The green LED on the processor PCB also indicates that the 5V rail of the switched mode power supply is intact Two different sets
135. ture which is accessed when Gfx is chosen from the SELECT OBJECT list under CAL TXD appears in figure 7 2 All these functions are associated with definitive calibration the purpose of which is to define the relationship between IR absorption and gas concentration This relationship is used for linearisation of the Gfx output and is mathematically derived from a set of experimental data points The importance of these data to the correct functioning of the instrument cannot be overestimated so extreme care should be exercised when performing any of the activities described below Experimental calibration data is specific to a particular Gfx bench and is therefore stored in the circuitry associated with the individual units The following functions are provided to transfer data between Gfx benches and the computer in the Xentra chassis UPLOAD This transfers data from the chassis to all the Gfx benches connected to it Uploading should only be necessary where the calibration data has been changed and then only when the integrity of this data is assured DOWNLOAD This transfers data from all the connected Gfx benches to the Xentra chassis It is necessary to perform a download operation when a replacement Gfx bench or a new EEPROM figure 7 1 8 or a new microprocessor PCB figure 7 1 1 containing a new EEPROM has been fitted to ensure that the instrument is operating with a correct calibration 7 3 3 7 3 4 7 3 5 If at the end o
136. ugh two base emitter junctions by IC3 pin 7 The voltage on IC5 pin 3 is applied to two more base emitter junctions one of which has a constant bias from R21 Due to the logarithmic characteristic of the base emitter junctions the current drawn into the collector of IC5 pin 5 is proportional to the square of the current in R30 This circuit therefore measures the heater voltage and produces a current proportional to the heater power Soft Start Initially C24 is uncharged so holding TR3 drain low The current drawn through R14 limits the initial heater power As C24 charges up the current through R14 drops and the power limit increases Heater Driver The heater demand current in R12 is subtracted from the heater power current in IC5 pin 5 and integrated by C25 When the voltage on IC3 pin 8 drops to zero the comparator IC6 pin 13 goes high to enable another heater pulse 3 13 3 14 Zero Crossing Switch The comparator IC6 pin 14 senses the two AC inputs and pulls low to inhibit heater pulses except when the AC is near a zero crossing point Full Cycle Heater Pulses The comparator IC6 pin 1 has hysteresis to provide a clock to IC10 pin 3 which is connected as a divide by 2 This signal is used to clock IC10 pin 11 on each mains cycle Heater Output Transistor TR2 drives the two triacs which supply a symmetrical voltage to the heater When the heater is not driven resistors R18 and R19 pull the heater to ground
137. ules may be plugged into any of four positions on the Multiplexer board Signal multiplexing Refer to figure 6 4 The Sensor interface board 2 has one digital input and one analogue input for interfacing with transducers Analogue and digital signals are multiplexed into these inputs using three probe select or transducer select lines to select which transducer is accessed and four control lines to select which signal within the transducer is to be accessed The multiplexers are on the Multiplexer board the probe select and control lines are generated from the Sensor interface board Signal scaling The gas sensor modules used in the Xentra output 0 to 1 V signals the Multiplexer board re scales the signals The signals are multiplied by 2 and a 0 5 V offset added finally the signals are potted down to 80 The A to D has a full scale of 2 5V The 0 5V offset provides under range and the 80 pot down provides over range 2 2 3 2 2 4 2 16 Removal of offset variation The 0 5V offset may vary In order to null out this variation the software accesses a OV input signal and measures the actual 0 5V level This offset null occurs once per minute Span voltage reference To reduce the span temperature coefficient of the electronics a span reference voltage is provided which is read once every ten seconds If the resultant reading is outside of acceptable limits the A D convertor is re calibrated If the reading is still
138. use F1 Blown D11 LED off a Source Continuity Broken Source LED Source connector not fully inserted Faulty Housekeeping PCB Figure 5 2 Gfx fault icon on diagnosis tree The following checks and investigations should be carried out The D16 LED bench OK LED is off Measurements and diagnosis Check that at least one other LED on the Housekeeping PCB is off If all other LEDs are on change the Housekeeping PCB If another LED is off go to the respective point in the Investigation procedure 5 35 5 36 The D15 LED power OK LED is off Measurements and diagnosis a Check the fuse F2 Replace the fuse if it is blown and retest If the fuse blows again then replace the Housekeeping PCB If the fuse is OK and the D15 LED is still off then replace the Housekeeping PCB Check the power supply on pins 5 and 7 of connector PL3 An ac voltage of approximately 36 volts should be present If the supply voltage is faulty then disconnect the PL3 connector and check the voltage again If the voltage is now OK then replace the Housekeeping PCB Otherwise check the voltage on the transformer and replace if faulty If the transformer is OK then check the Multiplexer PCB the transformer and the cable connectors The D13 LED motor in synchronisation is off Measurements and diagnosis a Check that the motor is rotating freely If the motor is not rotating freely check for foreign bodies or any other damage Id
139. volt for V gn when the sample concentration is 500 ppm CO IC8 pin 8 9 and 10 provides a buffer for the diagnostic output TP1 This signal shows all four sampled and averaged signals superimposed on the input signal received from the pre amp PCB The Housekeeping PCB 01210903 Refer to circuit diagram 01210 103 The Housekeeping PCB provides the required voltages for the chopper wheel motor and for the IR source In order to avoid the effects of the ambient temperature on the CO concentration the chopper box and the signal processing board are kept to a constant temperature of 70 C The PID heater control system is located on the housekeeping PCB On this PCB are also located the digital circuits which provide the logic for the sequential distribution of the four sample and hold circuits IC1 forms a P I D chopper box heater control system The temperature is sensed by a thermistor connected to PL1 pin 18 and 20 which in conjunction with R1 and R2 form a resistive voltage divider C2 R94 and IC1 pin 1 2 and 3 are wired in a differentiator configuration in order to produce an output signal proportional with the rate of change of the thermistor resistance The output signal is summed with the main thermistor signal to produce error rate damping The sum of these two signals is used as input for the other half of IC1 wired in an integrator configuration The output of this integrator pin 7 of IC1 will change as long as the voltage on pin 18
140. when the instrument is turned on If any of the transducers fails to achieve its normal temperature operating conditions within a specified time then the warm up icon will be turned off and a fault icon raised Fault icon This icon is displayed if a fault condition is identified within the analyser The cause of the fault may be identified from the user interface see section 1 9 Displaying faults present The Xentra menu display To initiate any user interface menu operation the MENU key should be pressed The Xentra will then present the top level menu which in turn leads on to other menus A tree showing the menu structure in its entirety is given in figure 1 6 At each menu the user highlights the desired option using the arrow keys gt lt and then presses the ENTER key Reverse video is used to highlight the selected menu option Pressing the MEASURE key at any time returns to the measurement display The EDIT key is used as a short cut key Pressing the EDIT key will give more direct access to the edit functions provided to modify the text on the measurement display This includes the names of measured variables and the measurement units During any user interface operation the fundamental measurements are still being made by the Xentra and all relevant outputs alarms and diagnostics remain active The time and date are retained for at least two days while the analyser is switched off the configuration an
141. xample of an invalid data entry 9999 Last character should not be decimal point If an invalid data entry is made at a point in the user interface then the input will be ignored and the display return to the start of the data entry screen that precipitated the invalid entry No warning message will be generated NOTE If the Measure Menu or Quit keys are used to terminate a data entry rather than the Enter key then the data entered is lost Password protection Some user interface operations require the use of a password There are two passwords a supervisor password which gives access to SETUP and CALIBRATION and an operator password which gives access to CALIBRATION only Both of the passwords are factory set to 4000 these may be changed if required Transducer site numbering system The Xentra chassis may accommodate a number of internal transducers which are assigned site locations represented as 11 12 13 and 14 on the display Up to four transducers may be connected on separate gas streams so that two or more transducers of the same type may be present The site location code provides a means of distinguishing these transducers Output numbering system The outputs from the Xentra have a two digit identification number of the following format Card number Output e g the outputs fitted as standard in card position 1 are Analogue output Analogue output Relay Contacts normally open Relay Contacts normally
142. y eliminated by the use of gas filled filters The IR absorption spectrum of CO is not a smooth curve but consists of a number of distinct lines So while at low resolution the IR spectra of CO and CO for example overlap at high resolution they do not Band pass optical filters with sufficient resolution are not generally available Gas filled filters allow the transducer to selectively remove only those IR wavelengths directly associated with CO Refer to figure 3 2 An infrared source 1 produces broad band infrared energy A lens 2 is used to provide a collimated IR beam that passes to the transducer A band pass IR filter 4 selects only those wavelengths in the IR spectrum that are absorbed by CO Two small glass gas filled cells cuvettes one containing nitrogen 9 and the other one containing CO 3 are mounted on a wheel 8 A brush less DC motor 10 causes the wheel to rotate As the wheel rotates the infrared beam alternately goes through the nitrogen filled filter and the CO filled filter When the nitrogen filter is in position no absorption takes place and all of the IR energy passes through to the sample gas cell and detector When the CO filter is in position absorption takes place and the IR intensity of the wavelengths characteristic to CO is reduced The modulated IR beam passes through a gas filled sample cell 7 where some of the IR energy is absorbed The remaining IR energy passes through a condenser light

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