Guided Tours
Tour #3: Controlling Chamber Conditions
Using the LI-6400
3-35
6
View the graph
Press
4
, then
f3
to see the ongoing graph.
7
After 1 minute, change the reference target to 100 µmol mol
-1
.
When the
CO2S
curve flattens out, press
escape
2
f3
100
enter
, followed by
4
f3
to continue viewing the graph.
8
After one minute, change the reference target to 400 µmol mol
-1
.
Press
escape
2
f3
400
enter
4
f3
.
9
Redo Steps 5 through 7 with Flow = 100.
Reduce the flow rate, and repeat the cycle. Note the slower response of the
sample cell, and the faster response of the reference cell.
Your results should be similar to Figure 3-26.
Figure 3-26. Controlling on reference CO
2
concentration, with a closed, empty chamber. Note the
slower response of the sample cell (due to its larger volume) is aggravated at lower flow rates. Note
also the faster response when lowering CO
2
than when raising it.
b) Flow = 100 µmol s- 1
a) Flow = 500 µmol s- 1
Points to Remember
¥ Reference cell responds quicker than the sample cell, especially at low
flow rates.
¥ Controlling on reference concentration is faster than controlling on
sample concentration, for 3 reasons:
1. The larger volume of the sample cell / leaf chamber.
2. Flow changes when controlling constant humidity.
3. Possible photosynthetic rate changes
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 ...