Campbell CR1000X - Page 11

5.6.2 Example powerup.ini files 44
6. Measurements 46
6.1 Voltage measurements 46
6.1.1 Single-ended measurements 47
6.1.2 Differential measurements 47
6.1.2.1 Reverse differential 48
6.1.3 Improving voltage measurement quality 48
6.1.3.1 Deciding between single-ended or differential measurements 48
6.1.3.2 Minimizing ground potential differences 49
Ground potential differences 50
6.1.3.3 Detecting open inputs 50
6.1.3.4 Minimizing power-related artifacts 51
Minimizing electronic noise 52
6.1.3.5 Filtering to reduce measurement noise 53
CR1000X filtering details 53
6.1.3.6 Minimizing settling errors 54
Measuring settling time 54
6.1.3.7 Factors affecting accuracy 56
Measurement accuracy example 57
6.1.3.8 Minimizing offset voltages 57
Compensating for offset voltage 59
Measuring ground reference offset voltage 60
6.2 Current-loop measurements 61
6.2.1 Example Current-Loop Measurement Connections 62
6.3 Resistance measurements 63
6.3.1 Resistance measurements with voltage excitation 63
6.3.2 Strain measurements 66
6.3.3 AC excitation 68
6.3.4 Accuracy for resistance measurements 69
6.4 Thermocouple Measurements 69
6.5 Period-averaging measurements 70
6.6 Pulse measurements 71
6.6.1 Low-level ac measurements 73
6.6.2 High-frequency measurements 73
6.6.2.1 P terminals 74
6.6.2.2 C terminals 74
Table of Contents - iii