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4.1
The “Cable-Pod” Connectors ...................................................................................... 42
4.2
Connecting PRTs (4-wire) ............................................................................................ 42
4.3
Connecting PRTs (3-wire) ............................................................................................ 43
4.4
Connecting PRTs (2-wire) ............................................................................................ 43
4.5
Connecting Thermocouples (external Ice Point or WTP) ......................................... 44
4.6
Connecting Thermocouples (using RJ compensation)............................................... 45
4.7
Connecting Thermistors ............................................................................................... 45
5
GOOD PRACTICE GUIDELINES.................................................... 47
5.1
Looking After Your microK ........................................................................................ 47
5.2
Making a Good Electrical Measurement .................................................................... 47
6
THE MICROK TECHNOLOGY........................................................ 50
6.1
The ADC ........................................................................................................................ 50
6.2
Substitution Topology................................................................................................... 52
6.3
Minimising Thermal EMFs.......................................................................................... 54
6.4
Solid-State Switching .................................................................................................... 55
6.5
Inherent Stability .......................................................................................................... 55
6.6
Eliminating Self-Heating Effects ................................................................................. 56
7
7.1
7.2
CALIBRATION ................................................................................ 57
Checking Calibration.................................................................................................... 57
7.1.1
Checking the Master Current Source..........................................57
7.1.2
Resistance Measurements ..........................................................58
7.1.2.1 Zero Ohms Check ..................................................................58
7.1.2.2 400 Internal Reference Resistor..........................................59
7.1.2.3 100 Internal Reference Resistor..........................................60
7.1.2.4 25 Internal Reference Resistor ...........................................60
7.1.2.5 10 Internal Reference Resistor ...........................................60
7.1.2.6 1 Internal Reference Resistor .............................................60
7.1.3
Voltage Measurements...............................................................61
7.1.3.1 Zero Voltage Offsets..............................................................61
7.1.3.2 Voltage Span Check...............................................................61
Adjusting Calibration................................................................................................... 62
7.2.1
Calibrate Master Current Source ................................................63
7.2.1.1 Calibrating the 400 Internal Reference Resistor..................64
7.2.1.2 Calibrating the 100 Internal Reference Resistor..................65
7.2.1.3 Calibrating the 25 Internal Reference Resistor....................65
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Issue: 1.01