
Teledyne ML – T101 Operation Manual TABLE OF CONTENTS
xiii
9.5.12. PMT Sensor........................................................................................................................... 232
9.5.13. PMT Preamplifier Board ......................................................................................................... 232
9.5.14. PMT Temperature Control PCA............................................................................................... 232
9.5.15. High Voltage Power Supply.................................................................................................... 234
9.5.16. Pneumatic Sensor Assembly.................................................................................................. 234
9.5.16.1. Sample Pressure ............................................................................................................ 234
9.5.17. IZS Option ............................................................................................................................ 234
9.5.18. Box Temperature.................................................................................................................. 235
9.5.19. PMT Temperature.................................................................................................................. 235
9.6. Repair Procedures.......................................................................................................................... 235
9.6.1. Disk-on-Module Replacement .................................................................................................. 235
9.6.2. Adjusting the UV Lamp (Peaking the Lamp)............................................................................. 236
9.6.3. Replacing the UV Lamp ........................................................................................................... 238
9.6.4. Factory Cal (PMT Sensor, Hardware Calibration)...................................................................... 239
9.7. Frequently Asked Questions (FAQs)................................................................................................ 241
9.8. Technical Assistance....................................................................................................................... 242
10. PRINCIPLES OF OPERATION...........................................................................................................245
10.1. Measurement Principle ................................................................................................................. 245
10.1.1. H2S Conversion..................................................................................................................... 245
10.1.2. SO2Ultraviolet Fluorescence ................................................................................................. 246
10.2. The UV Light Path......................................................................................................................... 249
10.2.1. UV Source Lamp.................................................................................................................... 249
10.2.2. The Reference Detector......................................................................................................... 250
10.2.3. The PMT................................................................................................................................ 250
10.2.4. Optical Filters........................................................................................................................ 251
10.2.4.1. UV Source Optical Filter.................................................................................................. 251
10.2.4.2. PMT Optical Filter........................................................................................................... 251
10.2.5. Optical Lenses....................................................................................................................... 252
10.2.6. Measurement Interferences................................................................................................... 253
10.2.6.1. Direct Interference......................................................................................................... 253
10.2.6.2. UV Absorption by Ozone................................................................................................. 254
10.2.6.3. Dilution.......................................................................................................................... 254
10.2.6.4. Third Body Quenching.................................................................................................... 254
10.2.6.5. Light Pollution ................................................................................................................ 254
10.3. Pneumatic Operation.................................................................................................................... 255
10.3.1. Sample Gas Flow................................................................................................................... 256
10.3.2. Multigas Measurement & H2S SO2Switching Valve............................................................ 257
10.3.3. Flow Rate Control.................................................................................................................. 257
10.3.3.1. Critical Flow Orifice......................................................................................................... 257
10.3.4. Sample Particulate Filter........................................................................................................ 258
10.3.5. Hydrocarbon Scrubber (Kicker).............................................................................................. 259
10.3.6. SO2Scrubber........................................................................................................................ 259
10.3.7. Pneumatic Sensors................................................................................................................ 260
10.3.7.1. Sample Pressure Sensor................................................................................................. 260
10.3.7.2. Sample Flow Sensor....................................................................................................... 260
10.4. Electronic Operation..................................................................................................................... 261
10.4.1. CPU....................................................................................................................................... 263
10.4.1.1. Disk On Module (DOM)................................................................................................... 263
10.4.1.2. Flash Chip...................................................................................................................... 263
10.4.2. Sensor Module & Sample chamber......................................................................................... 264
10.4.3. Sample Chamber Heating Circuit ........................................................................................... 264
10.4.4. Photo Multiplier Tube (PMT)................................................................................................... 265
10.4.5. PMT Cooling System.............................................................................................................. 266
10.4.5.1. Thermoelectric Cooler (TEC)........................................................................................... 266
10.4.5.2. TEC Control Board.......................................................................................................... 267
10.4.6. PMT Preamplifier................................................................................................................... 267
10.4.7. Pneumatic Sensor Board........................................................................................................ 269
10.4.8. Relay Board.......................................................................................................................... 269
10.4.8.1. Heater Control................................................................................................................ 269
10.4.8.2. Valve Control................................................................................................................. 269
10.4.9. Status LEDs & Watch Dog Circuitry........................................................................................ 270
10.4.10. Motherboard........................................................................................................................ 271