Calibration Issues
CO2 and H2O Analyzers
Using the LI-6400
18-15
The
ÒIRGA SpanÓ
Program Displays
The display of the spanning program changed a bit with OPEN 3.2
(Figure 18-8).
What Can Go Wrong Setting the Span
The span factors should be within 0.05 of 1.0 (that is, 0.95 to 1.05)
5
. The far-
ther out of this range you go in attempting to make the analyzer read the cor-
rect concentration, the more likely it is that something is wrong:
¥
Badly zeroed analyzer
Make sure you have a good zero before setting the span.
¥
Concentration not what you think it is
(CO
2
) Has the span gas ever been independently checked? DonÕt believe even
the most reputable vendor of calibration gasses; after all, someone could have
accidentally put the wrong label on the tank sent to you.
(H
2
O) Is there water in the condensor? Are you asking for a target that is at
or above the room temperature? (You wonÕt get that dew point, of course, but
you will get trouble in the form of condensation somewhere in the line.)
¥
Leak in the chamber
The chamber has to be well sealed for this to work.
5.
Starting in version 3.2, you are not allowed to adjust the span outside of the
range 0.9 to 1.1.
Version 3.01 and below
Version 3.2 and above
Figure 18-8. The ÒIRGA SpanÓ programÕs display changed a bit with OPEN 3.2.
Prior to this version, CO
2
concentrations and mV values were shown together,
and dew points and mole fractions were shown together for water vapor. With
3.2, CO
2
and dew points are shown. If you need to see water mole fractions, keep
pressing
¬
or
®
until they appear.
CO2R_µml CO2R_mV
CO2S_µml CO2S_mV
CO2Rµml
CO2Sµml Td_R_¡C Td_S_¡C
H2OR_mml Td_C
H2OS_mml Td C
CO2Rµml CO2Sµml H2ORmml
H2OSmml
Summary of Contents for LI-6400
Page 1: ...Using the LI 6400 Portable Photosynthesis System ...
Page 15: ...Part I The Basics ...
Page 16: ......
Page 174: ...Making Measurements Answers to Questions 4 56 Using the LI 6400 4 ...
Page 175: ...Part II Useful Details ...
Page 176: ......
Page 200: ...Standard Tools Power ON Hooks 5 24 Using the LI 6400 5 ...
Page 214: ...Real Time Data Real Time Graphics 6 14 Using the LI 6400 6 ...
Page 234: ...Environmental Control Light Control 7 20 Using the LI 6400 7 ...
Page 244: ...Light Sensor Considerations Gallium Arsenide Phosphide GaAsP Sensor 8 10 Using the LI 6400 8 ...
Page 288: ...Data Logging Making Your Own AutoPrograms 9 44 Using the LI 6400 9 ...
Page 289: ...Part III Working With Files ...
Page 290: ......
Page 312: ...The LPL File System Troubleshooting 10 22 Using the LI 6400 10 ...
Page 340: ...Downloading Files Using a Data Capture Program 11 28 Using the LI 6400 11 ...
Page 375: ...Part IV Configuration Issues ...
Page 376: ......
Page 420: ...Defining User Variables Old Style vs New Style 15 18 Using the LI 6400 15 ...
Page 454: ...Using an Energy Balance Further Reading 17 12 Using the LI 6400 17 ...
Page 455: ...Part V Maintenance Troubleshooting ...
Page 456: ......
Page 572: ...Troubleshooting Useful Information 20 46 Using the LI 6400 20 ...
Page 593: ...Part VI Programming ...
Page 594: ......
Page 622: ...Programming with LPL Compiler Directives 22 28 Using the LI 6400 22 ...
Page 846: ...Index I 16 Using the LI 6400 ...