Guided Tours
Tour #3: Controlling Chamber Conditions
3-36
Using the LI-6400
3
Temperature Control
Temperature control has two target options: a constant block temperature (the
block is the metal block that encompasses the sample and reference cells of
the IRGA), or constant leaf temperature.
has details, but the next two experiments illustrate the differences.
Experiment #7
Controlling on Block Temperature
This is the more direct and stable of the temperature control options.
1
Determine the ambient temperature.
Display line
h
of the default display map has block, air, and leaf temperatures.
Note the block temperature.
2
Set block target to 3¡ cooler than current value
Press
2
f4
B
<
value
- 3>
enter
(where
value
is the block temperature from Step
1). The external fans on either side of the chamber should start to run. Watch
the block temperature slowly drop to this new target value.
3
Note the temperature gradient
You should see that
Tblock
<
Tair
<
Tleaf
.
4
Now make the target 3 degrees warmer than ambient
Press
f4
<
value
+ 3>
enter
. The block temperature will rise a bit faster to this
new target. Heating is always more efficient than cooling.
5
Note the temperature gradient
You should see that
Tblock
>
Tair
>
Tleaf
.
Points to Remember
¥ Controlling on block temperature is slow but steady.
¥ Limit of control is generally within 7 degrees of ambient.
¥ The further
Tblock
is from ambient, the larger the temperature gradient
through the leaf chamber and IRGA.
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 ...