Specifications
CR1000 Table of Contents
ii
3.1.7 Security...................................................................................... 3-10
3.1.8 Care and Maintenance ............................................................... 3-10
3.1.8.1
Protection from Water ..................................................... 3-10
3.1.8.2 Protection from Voltage Transients................................. 3-11
3.1.8.3 Calibration....................................................................... 3-11
3.1.8.4 Internal Battery................................................................ 3-11
3.2 PC Support Software .......................................................................... 3-11
3.3 Specifications...................................................................................... 3-13
4. Sensor Support ........................................................ 4-1
4.1 Powering Sensors ................................................................................. 4-1
4.1.1 Switched Precision (-2500 to +2500 mV)................................... 4-1
4.1.2 Continuous Regulated (5 Volt) ................................................... 4-1
4.1.3 Continuous Unregulated (Nominal 12 Volt)............................... 4-2
4.1.4 Switched Unregulated (Nominal 12 Volt) ......................................... 4-2
4.2 Voltage Measurement........................................................................... 4-2
4.2.1 Measurement Sequence............................................................... 4-3
4.2.2 Voltage Range............................................................................. 4-4
4.2.3 Offset Voltage Compensation ..................................................... 4-5
4.2.3.1
Input and Excitation Reversal (RevDiff, RevEx = True) .. 4-6
4.2.3.2 Ground Reference Offset Voltage (MeasOff = True)........ 4-7
4.2.3.3 Background Calibration (RevDiff, RevEx, MeasOff
= False) .......................................................................4-7
4.2.4 Measurements Requiring AC Excitation..................................... 4-7
4.2.5 Integration ................................................................................... 4-8
4.2.5.1 AC Power Line Noise Rejection........................................ 4-8
4.2.6 Signal Settling Tim
e.................................................................. 4-10
4.2.6.1 Minimizing Settling Errors
.............................................. 4-11
4.2.6.2 Measuring the Neces
sary Settling Time .......................... 4-11
4.2.7 Self-Calibration ......................................................................... 4-13
4.3
Bridge Resistance Measurements ....................................................... 4-16
4.3.1 Strain Calculations .................................................................... 4-19
4.4
Thermocouple Measurements............................................................. 4-21
4.4.1 Error Analysis ........................................................................... 4-21
4.4.1.1 Panel Temperature ........................................................... 4-22
4.4.1.2 Thermocouple Limits of Error......................................... 4-24
4.4.1.3 Accuracy of Thermocouple Voltage Measurement ......... 4-25
4.4.1.4 Noise on Voltage Measurement....................................... 4-26
4.4.1.5 Thermocouple Polynomial: Voltage to Tem
perature...... 4-26
4.4.1.6 Reference Junction Compensation: Temperature to
Voltage
...................................................................... 4-27
4.4.1.7 Error Summary ................................................................ 4-28
4.4.1.8 Use of External Reference Junction................................. 4-28
4.5
Pulse Count Measurement .................................................................. 4-29
4.5.1 Pulse Input Channels P1 and P2................................................ 4-30
4.5.1.1 High-frequency Pulse ...................................................... 4-31
4.5.1.2 Low-Level AC................................................................. 4-32
4.5.1.3 Switch Closure................................................................. 4-32
4.5.2 Digital I/O Ports
for Pulse Counting ......................................... 4-32
4.6
Period Averaging Measurements........................................................ 4-33
4.7 SDI-12 Measurements ........................................................................ 4-34
4.8 RS-232 Measurements........................................................................ 4-34
4.9 Field Calibration of Linear Sensor...................................................... 4-34