Fluke 2625A User Manual

2-1

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