TDR SOIL MOISTURE MEASUREMENTS
TABLE OF CONTENTS
PAGE
Warranty and Assistance
1.
INTRODUCTION
........................................................................................................................ 1
1.1
Soil Moisture Measurement by Time Domain Reflectometry .................................................... 1
1.2
Probes and Cables .................................................................................................................... 1
1.3
Multiplexing................................................................................................................................ 1
2.
SYSTEM COMPONENTS
....................................................................................................... 2
3.
INSTALLATION
.......................................................................................................................... 2
3.1
Assigning Addresses ................................................................................................................. 3
3.2
Installing 1502B in ENC TDR .................................................................................................... 4
3.3
Datalogger Wiring...................................................................................................................... 4
3.3.1
SDM Wiring......................................................................................................................... 4
3.3.2
PS1502B ............................................................................................................................. 5
3.4
Soil Probes ................................................................................................................................ 5
3.5
Grounding.................................................................................................................................. 6
3.6
Battery Connections .................................................................................................................. 6
4.
PROGRAMMING INSTRUCTION 100
................................................................................ 6
5.
CALIBRATION FOR WATER CONTENT
.......................................................................... 7
6.
PROGRAMMING EXAMPLES
.............................................................................................. 8
6.1
Example 1, Measure and Record Every Hour ........................................................................... 8
6.2
Example 2, Hourly Average Using Topp's Calibration............................................................... 9
6.3
Example 3, TDR Measurements in Table 2 with Analog Measurements in Table 1 ............... 10
TABLES
3-1
SDM Addresses......................................................................................................................... 4
4-1
Waveform Resolution Determined by Probe Length ................................................................. 7
FIGURES
2-1
TDR System Components......................................................................................................... 2
3-1
Address Switch on SDM1502.................................................................................................... 3
3-2
Location of Address Jumpers on SDMX50 ............................................................................... 3
3-3
Mounting 1502B in ENC TDR.................................................................................................... 4
3-4
SDM Wiring ............................................................................................................................... 5
3-5
PB30 Assembly ......................................................................................................................... 5
3-6
Terminal Strip Adapters for Connections to Battery .................................................................. 6
5-1
Comparison of Calibrations from Topp and Ledieu................................................................... 8
