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Campbell Scientific AVW200 AVW200-series Vibrating Wire Interfaces - Page 18

Temperature, AVW200-series 2-Channel Vibrating Wire Spectrum Analyzer Modules,

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AVW200-series 2-Channel Vibrating Wire Spectrum Analyzer Modules Response Amplitude Resonant Frequency Beginning Amplitude Noise Amplitude Noise Frequency Ending Amplitude FIGURE 2-2. DevConfig plots showing the AVW200 measurement approach. Please note that the use of the special FFT algorithm to achieve better noise immunity does require time for computation, which limits the maximum vibrating wire measurement rate to 2 seconds per sensor. Running a program at rates faster than this will result in compile/download errors. Read more! You can find Troubleshoot tool information in Section 5.5 and Appendix F; and detailed programming information in Section 6. 2.2 Temperature The AVW200 contains a completion resistor for measuring the internal thermistor contained in many vibrating wire sensors. The thermistor's resistance changes with the internal temperature of the sensor. This temperature can be used to correct errors in the vibrating wire measurement due to thermal expansion/contraction of the sensor body. The temperature correction is often used when the temperature of the medium that the sensor is measuring is changing (e.g. water temperature in a river or shallow lake). Temperature is calculated by applying the resistance to a known equation such as the Steinhart-Hart equation. The Steinhart-Hart coefficients for your sensor are found in the sensor's user manual. 10

Section	Page
Revision and Copyright Information	1
Warranty	3
Assistance	4
Table of Contents	5
1. Overview	9
1.1 Design Features	9
1.2 Specifications	11
1.3 Communication	11
1.3.1 Datalogger	11
1.3.1.1 PakBus Protocol/Direct RS-232 Connection	12
1.3.1.2 PakBus Protocol/Wireless Connection	12
1.3.1.3 PakBus Protocol/MD485 Communication	12
1.3.1.4 SDI-12 Communication Mode	12
1.3.2 Computer	13
1.3.2.1 Device Configuration Utility	13
1.3.2.2 LoggerNet	13
1.3.2.3 Terminal Commands	13
1.4 Use with Multiplexers	13
2. Measurements	15
2.1 Vibrating Wire	15
2.2 Temperature	18
3. Quick Start Guides	19
3.1 One or Two Sensors (no multiplexers)	19
3.1.1 Direct RS-232 Connection	19
3.1.2 Wireless Connection	20
3.2 Multiplexers Controlled by AVW200	22
3.2.1 Direct RS-232 Connection	22
3.2.2 Wireless Connection	23
3.3 Multiplexers Controlled by Datalogger	25
3.3.1 SDI-12 Communication	25
4. Connections	26
4.1 Sensor Wiring (no multiplexers)	26
4.2 Power and Ground	27
4.3 Datalogger Wiring (Direct Connection)	28
4.4 Wireless Connections (AVW206, AVW211, AVW216)	29
4.5 Multiplexer Wiring	30
4.5.1 AVW200 Controlling the Multiplexer	30
4.5.2 Datalogger Controlling the Multiplexer	31
5. Device Configuration (DevConfig) Utility	33
5.1 Connecting to DevConfig	33
5.2 Deployment Tab	34
5.2.1 Communications	34
5.2.2 Measurement	37
5.3 Data Monitor	38
5.4 Send OS	40
5.5 Troubleshoot	41
5.6 Settings Editor	44
5.7 Terminal	44
6. Programming	45
6.1 AVW200 Instruction	45
6.1.1 Pipeline Mode	49
6.1.2 Sequential Mode	49
6.2 SDI-12 Measurements	50
6.2.1 SDI12 Recorder() Instruction	50
6.2.2 Extended SDI-12 Commands	52
6.2.3 Use with Multiplexers	52
7. Example Programs	53
7.1 AVW200() Instruction (no multiplexers)	53
7.1.1 Direct RS-232 Connection (two sensors)	53
7.1.2 Wireless/One Sensor/Resistance Converted to Temperature	54
7.2 AVW200() Instruction Controlling Two Multiplexers	55
7.3 AVW200( ) Instruction Running in the Pipeline Mode	56
7.4 AVW200( ) Instruction Running in the Sequential Mode	57
7.4.1 AVW200 Controlling Two Multiplexers in Sequential Mode	58
7.4.2 Datalogger Controlling Two Multiplexers in Sequential Mode	58
7.5 SDI-12 Example	59
8. Troubleshooting Communication Problems	62
8.1 Unable to Communicate with DevConfig or Terminal Emulator	62
8.2 Datalogger to AVW200 Communication	62
8.3 Wireless Communications	62
Appendix A. Conversion from Hertz	65
A.1 Displacement Example	65
Appendix B. Thermistor Information	67
B.1 Converting Resistance to Temperature	67
B.1.1 Resistance Conversion Example – Geokon Sensor	67
B.2 Accuracy and Resolution	67
Appendix C. Antennas, Antenna Cables, and Surge Protectors for the AVW206, AVW211, and AVW216	71
C.1 Antennas	71
C.2 Antenna Cables	75
C.3 Surge Protectors	75
C.3.1 Electrostatic Issues	75
C.3.2 Antenna Surge Protector Kit	76
C.4 Part 15 FCC Compliance Warning	76
Appendix D. The Public Table	79
D.1 Forced Measurement Program	82
Appendix E. Status Table	83
Appendix F. Time Series and Spectrum Graph Information	87
F.1 Good Sensor Examples	87
F.2 Good Sensors with Noise	89
Appendix G. CR10X Programming Example	91
Appendix H. Additional Programming Examples	93
H.1 AVW200-Controlled Multiplexer	93
H.1.1 Direct RS-232 Connection	93
H.1.2 Wireless/Sensors with Different Frequencies	96
H.2 Datalogger-Controlled Multiplexer	99
Appendix I. Using MD485 Multidrop Modems with AVW200 Interfaces	105
I.1 Required Settings	105
I.2 Connections	106
I.2.1 Datalogger to MD485	107
I.2.2 MD485 to MD485	107
I.2.3 MD485 to AVW200	108
I.2.4 Multiplexer Connections	108
I.3 Programming	108
I.3.1 Example Program	108