Thermo 42i - Page 9

Contents
Thermo Electron Corporation Model 42i Low Source Instruction Manual ix
Front Panel Board Replacement............................................7-45
LCD Module Replacement ...................................................7-46
Service Locations...................................................................7-47
Chapter 8 System Description.........................................................................8-1
Hardware ................................................................................8-1
NO
2
-to-NO Converter...........................................................8-2
Mode Solenoid.....................................................................8-2
Reaction Chamber ...............................................................8-2
Optical Filter .......................................................................8-3
Pressure Transducer .............................................................8-3
Ozonator.................................................................................8-3
Ozonator Flow Switch .........................................................8-3
Photomultiplier Tube .............................................................8-3
Photomultiplier Tube Cooler..................................................8-3
Pump ......................................................................................8-3
Sample Capillary..................................................................8-3
Dry Air Capillary .................................................................8-4
Ammonia Scrubber .................................................................8-4
Software..................................................................................8-4
Instrument Control..............................................................8-4
Monitoring Signals...............................................................8-4
Measurement Calculations ...................................................8-5
Output Communication......................................................8-5
Electronics ..............................................................................8-6
Motherboard........................................................................8-6
Measurement Interface Board ..............................................8-7
Pressure Sensor Assembly .....................................................8-7
Temperature Control Board.................................................8-8
PMT Power Supply Assembly..............................................8-8
Input Board Assembly..........................................................8-8
Digital Output Board...........................................................8-8
I/O Expansion Board (Optional) .........................................8-9
Front Panel Connector Board ..............................................8-9
I/O Components ....................................................................8-9
Analog Voltage Outputs.......................................................8-9
Analog Current Outputs (Optional) ..................................8-10
Analog Voltage Inputs (Optional)......................................8-10
Digital Relay Outputs ........................................................8-10
Digital Inputs.....................................................................8-11
Serial Ports.........................................................................8-11
RS-232 Connection ...........................................................8-11
RS-485 Connection ...........................................................8-12
Ethernet Connection..........................................................8-12
External Accessory Connector ............................................8-12