OPENÕs System Variables
Measured Variables
14-4
Using the LI-6400
14
Measured Variables
These system variables are measured signals or computed quantities associ-
ated with the various analog sensors of the LI-6400. This section discusses
analog measurements and computations, presenting equations for each sensor
used.
Pressure
Atmospheric pressure P (kPa) is measured with a transducer located in the
console of the LI-6400. The signal (mV) is
V
p
.
ID: -11
1
(14-1)
where
a
p0
and
a
p1
are the 1
st
and 2
nd
calibration coefficients respectively
specified by the configuration command
2
CalPress= <
a
p0
> <
a
p1
>
Air Temperature
The air temperature within the IRGA sample cell
T
a
(C) is computed from the
signal
V
a
(mV) of a linearized thermistor located just beneath the circulation
fan in the sample IRGA (shown in Figure 19-26 on page 19-31). The equation
is
ID: -9
(14-2)
Block Temperature
The temperature
T
b
(C) of the metal block containing the optical path of the
IRGAs is also measured with a linearized thermistor, whose signal (mV) is
V
b
.
ID: -8
(14-3)
1.
These ID numbers refer to the system ID number. See Table 14-8 on page 14-19.
P
a
p
0
a
p
1
V
p
+
=
2.
Configuration commands are discussed in Chapter 16.
T
a
V
a
100
---------
=
T
b
V
b
100
---------
=
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 ...