Theory Of Operation - Fluke 2640A Service Manual

2-1. Introduction ............................................................................................ 2-5
2-2. Functional Block Description................................................................. 2-5
2-3. A1 Main PCA Block Description ...................................................... 2-7
2-4. Power Supply................................................................................ 2-7
2-5. Digital Kernel ............................................................................... 2-7
2-6. Serial Communication (Guard Crossing) ..................................... 2-8
2-7. Digital Inputs and Outputs............................................................ 2-8
2-8. Ethernet Interface ......................................................................... 2-8
2-9. A2 Display PCA Block Description .................................................. 2-8
2-10. A3 A/D Converter PCA Block Description....................................... 2-8
2-11. Analog Measurement Processor ................................................... 2-9
2-12. Input Protection ............................................................................ 2-9
2-13. Input Signal Conditioning ............................................................ 2-9
2-14. Analog-to-Digital (a/d) Converter................................................ 2-9
2-15. Inguard Microcontroller ............................................................... 2-9
2-16. Channel Selection......................................................................... 2-9
2-17. Open Thermocouple Check .......................................................... 2-10
2-18. A4 Analog Input PCA Block Description ......................................... 2-10
2-19. 20-Channel Terminals .................................................................. 2-10
2-20. Reference Junction Temperature.................................................. 2-10
2-21. Detailed Circuit Description .................................................................. 2-10
2-22. A1 Main PCA Circuit Description..................................................... 2-10
2-23. Power Supply Circuit Description................................................ 2-10
2-24. Raw DC Supply ........................................................................ 2-11
2-25. Auxiliary 6V Supply................................................................. 2-11
2-26. 5V Switcher .............................................................................. 2-11
2-27. Inverter...................................................................................... 2-12
2-28. Inverter Outguard Supply ......................................................... 2-12
2-29. Inverter Inguard Supply............................................................ 2-13
2-30. Power Fail Detection ................................................................ 2-13

Theory of Operation

Title
Chapter 2
Page
2-1