Table of Contents Teledyne API T703/T703U Calibrator Operation Manual
xii
8.4.2. AC Main Power ................................................................................................................................... 172
8.4.3. DC Power Supply................................................................................................................................ 173
8.4.4. I2C Bus ................................................................................................................................................ 174
8.4.5. Touchscreen Interface ........................................................................................................................ 174
8.4.6. LCD Display Module ........................................................................................................................... 174
8.4.7. Relay PCA .......................................................................................................................................... 175
8.4.8. Photometer O3 Generator Pressure /Flow Sensor Assembly............................................................. 175
8.4.9. Motherboard........................................................................................................................................ 177
8.4.9.1. A/D Functions .............................................................................................................................. 177
8.4.9.2. Test Channel / Analog Outputs Voltage...................................................................................... 178
8.4.9.3. Status Outputs............................................................................................................................. 179
8.4.9.4. Control Inputs .............................................................................................................................. 180
8.4.9.5. Control Outputs ........................................................................................................................... 181
8.4.10. CPU .................................................................................................................................................. 181
8.4.11. RS-232 Communications.................................................................................................................. 182
8.4.11.1. General RS-232 Troubleshooting.............................................................................................. 182
8.4.11.2. Troubleshooting Calibrator/Modem or Terminal Operation....................................................... 182
8.4.12. Temperature Problems ..................................................................................................................... 183
8.4.12.1. Box / Chassis Temperature....................................................................................................... 183
8.4.12.2. Photometer Sample Chamber Temperature ............................................................................. 183
8.4.12.3. UV Lamp Temperature.............................................................................................................. 183
8.4.12.4. Ozone Generator Temperature ................................................................................................. 184
8.5. Troubleshooting the O3 Photometer ......................................................................................................... 184
8.5.1. Dynamic Problems with the O3 Photometer ....................................................................................... 184
8.5.1.1. Noisy or Unstable O3 Readings at Zero ...................................................................................... 184
8.5.1.2. Noisy, Unstable, or Non-Linear Span O3 Readings .................................................................... 185
8.5.1.3. Slow Response to Changes in Concentration............................................................................. 185
8.5.1.4. The Analog Output Signal Level Does Not Agree With Front Panel Readings........................... 185
8.5.1.5. Cannot Zero................................................................................................................................. 185
8.5.1.6. Cannot Span................................................................................................................................ 185
8.5.2. Checking Measure / Reference Valve ................................................................................................ 186
8.6. Trouble Shooting the O3 Generator .......................................................................................................... 186
8.6.1. Troubleshooting the O3 Generator in the T703................................................................................... 186
8.6.2. Troubleshooting the O3 Generator in the T703U................................................................................ 187
8.7. Repair Procedures .................................................................................................................................... 187
8.7.1. Repairing Sample Flow Control Assembly ......................................................................................... 187
8.7.2. Disk-On-Module Replacement Procedure.......................................................................................... 189
8.8. FAQ’s ........................................................................................................................................................ 190
8.9. Technical Assistance ................................................................................................................................ 190
9. PRINCIPLES OF OPERATION ........................................................................................ 191
9.1. Pneumatic Operation ................................................................................................................................ 191
9.1.1. Gas Flow Control ................................................................................................................................ 191
9.1.1.1. Photometer Critical Flow Orifice.................................................................................................. 192
9.1.2. Internal Gas Pressure Sensors........................................................................................................... 192
9.2. Electronic Operation ................................................................................................................................. 193
9.2.1. Overview ............................................................................................................................................. 193
9.2.2. Central Processing Unit (CPU) ........................................................................................................... 194
9.2.2.1. Disk On Module (DOM) ............................................................................................................... 195
9.2.2.2. Flash Chip ................................................................................................................................... 195
9.2.3. Relay PCA .......................................................................................................................................... 195
9.2.3.1. Valve Control ............................................................................................................................... 196
9.2.3.2. Heater Control ............................................................................................................................. 197
9.2.3.3. Relay PCA Status LEDs and Watch Dog Circuitry...................................................................... 197
9.2.3.4. Relay PCA Watchdog Indicator (D1)........................................................................................... 198
9.2.4. Motherboard........................................................................................................................................ 199
9.2.4.1. A to D Conversion ....................................................................................................................... 199
9.2.4.2. Sensor Inputs .............................................................................................................................. 199
9.2.4.3. Thermistor Interface .................................................................................................................... 199
07223C DCN6572