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Appendix C. Alternate EC100 Outputs
C-2
TABLE C-1. USB and RS-485 Output Elements
Data
Element
Description
Units or Comments
5
Sonic Diagnostic Flag
6
CO
2
Density
mg·m
–3
7
H
2
O Density
g·m
–3
8
Gas Diagnostic Flag
9
Air Temperature
°C
10
Air Pressure
kPa
11
CO
2
Signal Strength
Nominally 0.0 to 1.0
12
H
2
O Signal Strength
Nominally 0.0 to 1.0
13
Pressure Differential (used for EC155
only, disregard for IRGASON)
kPa
14
Source Housing Temperature
°C
15
Detector Housing Temperature
°C
16
Counter
Arbitrary
17
Signature
Arbitrary in
hexadecimal
FIGURE C-1. USB data output in terminal mode
The final data element in each row or output array is the signature which can
be used to identify transmission errors similar to a Cyclic-Redundancy-Check
(CRC). The signature is a four character hexadecimal value that is a function of
the specific sequence and number of bytes in the output array. To check for
transmission errors, the recording device (such as a PC or datalogger)
calculates its own signature using each transmitted byte until encountering the
transmitted signature. The computed signature and the transmitted signature are
compared. If they match, the data were received correctly
If signatures do not match, the data should be disregarded.
The block of code below is an example implementation of Campbell
Scientific’s signature algorithm in the programming language C. To generate
the signature of an output array of bytes, the
seed
needs to be initialized to
0xaaaa and a pointer passed to the first byte of the output array. The number of
Summary of Contents for EC150
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Page 67: ...Appendix B Filter Bandwidth and Time Delay B 4 ...
Page 75: ...Appendix D Useful Equations D 4 ...
Page 76: ...E 1 Appendix E Safety Data Sheets SDS E 1 Molecular Sieve Type 13X ...
Page 77: ...Appendix E Safety Data Sheets SDS E 2 ...
Page 78: ...Appendix E Safety Data Sheets SDS E 3 ...
Page 79: ...Appendix E Safety Data Sheets SDS E 4 ...
Page 80: ...Appendix E Safety Data Sheets SDS E 5 E 1 Magnesium Perchlorate ...
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Page 87: ...Appendix E Safety Data Sheets SDS E 12 E 2 Decarbite ...
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Page 91: ...Appendix E Safety Data Sheets SDS E 16 ...
Page 92: ...F 1 Appendix F Packing Information F 1 EC150 GH Packing Information ...
Page 93: ...Appendix F Packing Information F 2 F 2 EC150 SH Packing Information ...
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