Calibration Issues
View, Store Zeros & Spans
18-18
Using the LI-6400
18
The flow meterÕs zero has a slight temperature sensitivity, but the drift is typ-
ically less than 1 µmol s
-1
per 10 degrees C. The flow meter zero is controlled
by an analog output channel, and the value is displayed in the
"View, Store
Zeros & Spans"
program (page 18-18) under the Zeros column. The value
shouldnÕt change much from day to day, but checking it and setting it is so
easy, itÕs worth the effort to make sure.
View, Store Zeros & Spans
This entry in the Calib Menu launches a program that allows you to view the
current zero and span settings for the IRGAs, and the current flow meter zero.
You can also revert these values back to the power on or factory settings.
Store Reset Quit
Reset Options:
P - revert to PowerOn defaults
F - revert to Factory defaults
R - reset Reference IRGA
S - reset Sample IRGA
W - reset flow meter
Select a key
These values are the adjustment
terms
C
mr
and
C
ms
W
mr
and
W
ms
(14-6) on page 14-5. The values
should be between -2 and 2, typically.
These values are the gain factor
terms
G
cr
and
G
cs
G
wr
and
G
ws
in Equations (14-5) and (14-6) on
page 14-5. They should be between
0.95 and 1.05, typically.
These values are the
settings of the analog
output channels that
control offsets in the
IRGAs. These values
will be between
+/- 5000, but should
not be near either of
these extremes.
Figure 18-10. The ÒView,Store Zero&SpansÓ screen. The zero and span data for factory defaults and power on
defaults is stored in the file "/dev/parm1", along with a number of other settings.
Store the current
zero and span val-
ues as the Pow-
erOn Defaults
Set Flow Zero to 0.
Set sample IRGA zero to 0, span to 1.
Set reference IRGA zero to 0, span to 1.
PowerOn and Factory defaults are stored
in
“/dev/parm1”
.
µmol/mol
µmol/mol
mmol/mol
mmol/mol
Adjust
0.0
0.0
0.0
0.0
Calibration Parameters
1.012
1.007
0.987
0.991
Span
Zero
23.5
-23.5
42.5
107.9
220.1
CO2R:
CO2S:
H2OR:
H2OS:
FLOW:
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 ...