Fluke 2620A, Manual

Page: 49 / 310

2-1
Chapter 2
Theory of Operation (2620A/2625A)
Title Page
2-1. Introduction .......................................................................................... 2-3
2-2. Functional Block Description............................................................... 2-3
2-3. Main PCA Circuitry ......................................................................... 2-3
2-4. Power Supply............................................................................... 2-3
2-5. Digital Kernel .............................................................................. 2-3
2-6. Serial Communication (Guard Crossing) .................................... 2-6
2-7. Digital Inputs and Outputs........................................................... 2-6
2-8. A/D Converter PCA ......................................................................... 2-6
2-9. Analog Measurement Processor .................................................. 2-6
2-10. Input Protection Circuitry............................................................ 2-6
2-11. Input Signal Conditioning............................................................ 2-6
2-12. Analog-to-Digital (A/D) Converter ............................................. 2-6
2-13. Inguard Microcontroller Circuitry ............................................... 2-6
2-14. Channel Selection Circuitry......................................................... 2-7
2-15. Open Thermocouple Check Circuitry.......................................... 2-7
2-16. Input Connector Assembly............................................................... 2-7
2-17. 20 Channel Terminals.................................................................. 2-7
2-18. Reference Junction Temperature ................................................. 2-7
2-19. Display PCA .................................................................................... 2-7
2-20. Memory PCA (2625A Only)............................................................ 2-7
2-21. IEEE-488 Option (-05)..................................................................... 2-7
2-22. Detailed Circuit Description ................................................................ 2-7
2-23. Main PCA ........................................................................................ 2-7
2-24. Power Supply Circuit Description............................................... 2-8
2-32. Digital Kernel .............................................................................. 2-10
2-43. Digital I/O .................................................................................... 2-14
2-44. Digital Input Threshold 2-1. ........................................................ 2-15
2-45. Digital Input Buffers.................................................................... 2-15
2-46. Digital and Alarm Output Drivers ............................................... 2-15