iv
8.11 Fast Fourier Transform Examples .................................................... 8-22
8.12 Using the Switched 12V to Power Sensors....................................... 8-32
Part III Reference Manual
Section 9. Input / Output Processing Instructions....9-1
Section 10. Processing Instructions ........................ 10-1
Section 11. Output Processing Instructions ........... 11-1
Section 12. Program Control Instructions ............... 12-1
Section 13. CR10X Measurements ........................... 13-1
13.1 Fast and Slow Measurement Sequence............................................. 13-1
13.2 Single-Ended and Differential Voltage Measurements .................... 13-2
13.2.1 Effect of Continuously Powered Sensors on Single-Ended
Thermocouples....................................................................... 13-3
13.3 The Effect of Sensor Lead Length on Signal Settling Time ............. 13-4
13.3.1 The Input Settling Time Constant........................................... 13-4
13.3.2 Effect of Lead Length on Signal Rise Time ........................... 13-7
13.3.3 Transients Induced by Switched Excitation............................ 13-8
13.3.4 Summary of Settling Errors for Campbell Scientific
Resistive Sensors.................................................................. 13-10
13.4 Thermocouple Measurements......................................................... 13-13
13.4.1 Error Analysis ....................................................................... 13-14
13.4.2 Use of External Reference Junction or Junction Box ........... 13-18
13.5 Bridge Resistance Measurements ................................................... 13-19
13.6 Resistance Measurements Requiring AC Excitation ...................... 13-23
13.6.1 Influence of Ground Loop on Measurements ....................... 13-23
13.7 Calibration Process ......................................................................... 13-24
13.7.1 Automatic Calibration Sequence .......................................... 13-24
13.7.2 Instruction 24 Calibration ..................................................... 13-25
Section 14. Installation and Maintenance ................ 14.1
14.1 Protection from the Environment ..................................................... 14-1
14.2 Power Requirements......................................................................... 14-1
14.3 Campbell Scientific Power Supplies................................................. 14-2
14.3.1 Use of Rechargeable Batteries. ............................................... 14-2
14.4 Solar Panels ...................................................................................... 14-3
14.5 Direct Battery Connection to the CR10WP Wiring Panel ................ 14-3
14.6 Vehicle Power Supply Connections ................................................. 14-3
14.7 Grounding......................................................................................... 14-4
14.7.1 Protection From Lightning...................................................... 14-4
14.7.2 Effect of Grounding on Measurements: Common Mode
Range ..................................................................................... 14-5
14.8 CR10WP Wiring Panel..................................................................... 14-5
14.9 Use of Digital Control Ports for Switching Relays........................... 14-6
14.10 Maintenance.................................................................................... 14-7
14.10.1 Replacing the Internal Battery .............................................. 14-7