Chapter 6 • Maintenance
23
5
Fill a container of water with enough ice that it will not melt quickly.
6
Place the temperature sensor and thermometer into the container.
Turn on the power supply and the current meter. Let the sensor
stabilize for 30 minutes before taking any measurements.
7
Record the ice bath temperature, T
ICE
= _______, and record the
output current of the sensor, I
ICE
= _______.
8
Fill a container with enough warm water that it will not cool down
quickly.
9
Place the temperature sensor and thermometer into the container.
Turn on the power supply and the current meter. Let the sensor
stabilize for 30 minutes before taking any measurements.
10
Record the warm water temperature, T
WARM
= _______, and record
the output current of the sensor, I
WARM
= _______.
11
Calculate the relation between current and temperature:
a
Calculate the current difference:
I
WARM
– I
ICE
= _______ = ∆I.
b
Calculate the temperature difference:
T
WARM
– T
ICE
= _______ = ∆T.
c
Calculate I
B
I
WARM
– (∆I/∆T)(T
WARM
) = _______ = I
B
.
d
Calculate the low current value for the sensor:
(∆I/∆T) • (–50) + I
B
= _______ = I
HIGH
.
This current is the output current the sensor would produce if the
temperature were –50°C.
e
Calculate the high current value for the sensor:
(∆I/∆T) • 50 + I
B
= _______ = I
LOW
.
This current is the output current the sensor would produce if the
temperature were 50°C.
12
Use these new current values calibrate the system that is monitoring
the sensor output.
Summary of Contents for SolarMagic
Page 1: ...SolarMagicTM Weather Station User Guide...
Page 4: ......
Page 32: ......
Page 33: ...Appendix A Reference Diagrams 27 Appendix A Reference Diagrams...
Page 34: ...National Semiconductor SolarMagic Weather Station User Guide 28 A 1 1 Sensor Terminal Blocks...
Page 35: ...Appendix A Reference Diagrams 29 A 1 2 Communications Power Terminal Block...