Campbell Scientific 0871LH1 Freezing Rain Sensor User Manual
Page 4
1
TABLE OF CONTENTS
1
Purpose .............................................................................................................................................. 2
2
General ............................................................................................................................................... 2
3
Detailed Principle of Operation ........................................................................................................... 2
4
Specifications ..................................................................................................................................... 4
5
Physical Description ........................................................................................................................... 5
6
Temperature Considerations .............................................................................................................. 6
7
Power Interruptions ............................................................................................................................ 6
8
Mounting Considerations ................................................................................................................... 6
9
Wiring ................................................................................................................................................ 7
9.1
0871LH1CBL-L Wiring for Discrete Output ............................................................................... 7
9.2
0871LH1CBL-L Wiring for RS422 Output ................................................................................. 8
10
Program Examples .............................................................................................................................. 9
10.1
CR1000 Example – Discrete Outputs ....................................................................................... 9
10.2
CR23X Example – Discrete Outputs ....................................................................................... 10
10.3
CR1000 Example – RS422 Outputs ........................................................................................ 11
Appendix A:
1
RS-422 Output Format for non-Campbell Datalogger Applications ................................................... 17
2
Built In Test (BIT) ............................................................................................................................... 17
3
Hardware Built-In-Test (BIT) .............................................................................................................. 17
4
Continuous Built-In-Test (BIT) ........................................................................................................... 17
5
BIT Failure That Disables Ice Output .................................................................................................. 18
6
Operator-Initiated Tests .................................................................................................................... 19
7
Initiated Built-In-Test (BIT) ................................................................................................................. 19
8
Correlation Counting ........................................................................................................................ 20
9
Ice Detector RS-422 String Format .................................................................................................... 21
10
Electrostatic Discharge (ESD) Consideration ...................................................................................... 22
Appendix B:
1
Freezing Rain Sensor Block Diagram ................................................................................................. 23
1.1
Microcontroller ......................................................................................................................... 24
1.2
Watchdog/Reset Circuit ........................................................................................................... 24
1.3
Serial EEPROM ....................................................................................................................... 24
1.4
Probe Oscillator ....................................................................................................................... 24
1.5
Heater Control ......................................................................................................................... 24
1.6
Drive Coil ................................................................................................................................. 25
1.7
Feedback Coil ......................................................................................................................... 25
1.8
Heater ...................................................................................................................................... 25
1.9
DC Power Supply .................................................................................................................... 25
1.10
Status Output .......................................................................................................................... 25
1.11
Ice Signal Output ..................................................................................................................... 25
2
Qualification Capabilities .................................................................................................................. 26
3
Input/Output Specification ............................................................................................................... 27
3.1
Input/Output Pin Designations ................................................................................................. 27
TABLE OF FIGURES
Figure 1 MSO Circuit Sectional View .............................................................................................................................................. 3
Figure 2 MSO Circuit Schematic ...................................................................................................................................................... 3
Figure 3 Ice Detector ............................................................................................................................................................................ 5
Figure 4 Mounting (part number 0871LH1 MNT) .................................................................................................................... 6
Figure 5 General Hook-up Diagram ............................................................................................................................................... 8
Figure 6 Functional Block Diagram ............................................................................................................................................. 23