LI-COR 1400-101 User manual

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LI-COR Temperature Sensors
Operation and Installation Instructions
● 1400-101 (Replaces 1000-16)
● 1400-102 (Replaces 1000-16-2)
● 1400-103 (Replaces 1000-15)
Required Accessories
The 1400-101 Air Temperature Sensor, the 1400-102 Air Temperature Sensor, and the 1400-103 Soil Temperature Sensor can be used
with either the LI-1000 or LI-1400 Datalogger. Each of these sensors require either the 1000-05 Terminal Block, the 1000-06A AC
Terminal Block, 1000-10 Thermocouple Terminal Block or the 1400-301 Terminal Block. These sensors are not suitable for use with
the 1000-06 AC Terminal Block (purchased before April 15, 1987).
Connecting the Temperature Sensors
Each sensor is terminated with 3 wires which connect to the terminal block. The red lead also has a 33.2K ohm precision resistor connected
in series with the thermistor. The red lead is connected to the current input terminal for the channel being used. The black lead is con-
nected to the regulated +5 volt power supply, which is terminal C-9 on the 1000-05, C-9 on the 1000-06A, P1-3 on the 1000-10 or 5VDC
terminal on the 1400-301. The silver shield wire is connected to a signal ground terminal on the current channel in use.
1400-103 Installation. The soil temperature sensor is designed to be as small as possible to facilitate burial at any desired depth.
However, when burying the sensor at shallow depths (< 10 cm) there are some practical considerations which should be observed. At
depths less than 10 cm it is much easier for the sensor to be accidentally pulled out or to be uncovered by strong winds. This can
usually be prevented by burying not just the tip of the sensor but a length of the cable as well. It is also best to bury the sensor and the
cable at an angle to the soil surface (not perpendicular). If using the 1000-08 or 1400-201 Instrument Enclosure, the cable can be run
up through the bottom of the enclosure and connected to the LI-1000 or LI-1400.
1400-102 Installation. The 1400-102 air temperature sensor mounts in a hole in the bottom of the 1000-08 or 1400-201 Instrument
Enclosure and is held in place by two mounting collars which slide along the shaft of the temperature sensor. Take off one of the
collars and put the temperature sensor through the hole in the bottom of the enclosure. Replace the collar so that one is on either side
of the bottom of the instrument enclosure, and the tip of the air temperature sensor is one inch from the bottom of enclosure. In this
position the sensor will be correctly shaded by the shade ring and will still have good air circulation around it. NOTE: If the air
temperature sensor is installed in an older instrument enclosure (1000-08), the hole needs to be drilled out with a 0.5 inch drill bit so
the narrow end of the collars fit into the hole.
LI-1400 Configuration
The LI-1400 uses the Steinhart-Hart Equation to calculate temperature from LI-COR’s 1400-101, 102, and 103 temperature sensors.
Only a single set of coefficients is necessary and is preprogrammed into the LI-1400. When configuring a channel, select
Math=MLTHMSTR in the channel setup for any of these LI-COR temperature sensors.
LI-1000 Configuration
LI-COR temperature sensors are manufactured using non-linear thermistors. They are calibrated by calculating a polynomial to fit its
response curve. The calibration polynomial in the LI-1000 is of the form
Y = a0 + (a1)X + (a2)X2 + (a3)X3 + (a4)X4 + (a5)X5
where Y is the output of the thermistor in degrees Celsius; a0 through a5 are polynomial coefficients for the thermistor, and X is the
uncalibrated output of the thermistor. The calibration coefficients a0 through a5 are entered in memory in CONFIGURATION mode.
(over)
LI-1000
DataLogger
Fct
On/Off
Setup Enter
7
4
1
0
89
56
23
Esc
EEX
View
Shift
MP
T
XY Z
VU
RQ
NO
J
S
W
I
L
HG
K
C
F
B
E
A
D
data
LOGGER
LI-1400
model
AnalogI/O

Several sets of calibration coefficients for various temperature ranges are given below. These calibration coefficients apply to all
LI-COR temperature sensors. You should choose the set of calibration coefficients which best fits your climatic temperature range,
taking note that some of the sets of coefficients fit the sensor response curve better than others (e.g. some have a smaller RMS error
than others). Both the error and temperature range should be kept in mind when choosing a set of coefficients.
Thermistor Calibration Coefficients for LI-1000
NOTE: The RMS errors given below represent only the error contributed by the polynomial. The overall error for LI-COR tempera-
ture thermistors is typically ±0.5 °C at 25 °C.
Temperature Range: -10 to +50 °C RMS Error (°C) = 0.05603
a0 = -189.83
a1 = 9.5200
a2 = -0.21156
a3 = 0.0024517
a4 = -1.4110E-05
a5 = 3.2623E-08
Temperature Range: -20 to +60 °C RMS Error (°C) = 0.2014
a0 = -113.70
a1 = 5.6256
a2 = -0.13558
a3 = 0.0017472
a4 = -1.1021E-05
a5 = 2.7557E-08
Temperature Range: -30 to +70 °C RMS Error (°C) = 0.4193
a0 = -77.585
a1 = 3.4432
a2 = -0.086375
a3 = 0.0012267
a4 = -8.4243E-06
a5 = 2.2652E-08
Temperature Range: -40 to +80 °C RMS Error (°C) = 0.7538
a0 = -68.599
a1 = 2.8949
a2 = -0.075639
a3 = 0.0011509
a4 = -8.3521E-06
a5 = 2.3369E-08
Temperature Range: -80 to +40 °C RMS Error (°C) = 1.3889
a0 = -75.024
a1 = 3.6149
a2 = -0.10132
a3 = 0.0015474
a4 = -1.1134E-05
a5 = 3.0678E-08
Temperature Range: -80 to +140 °C RMS Error (°C) = 4.9890
a0 = -78.363
a1 = 4.5901
a2 = -0.15671
a3 = 0.0026749
a4 = -2.0518E-05
a5 = 5.7923E-08
®
LI-COR, inc. ●Environmental Division ●4421 Superior Street ●P.O. Box 4425 ●Lincoln, Nebraska 68504 USA
Phone: [phone] ● FAX: [phone]
Toll-free 1-800-447-3576 (U.S. & Canada)
E-mail: [e-mail]
Internet: http://www.licor.com LDL111-11/97