Campbell Scientific TORO® NW8002 Weather Station Installation - Manual (Page 30)

SECTION 3. TROUBLESHOOTING
3-3
The line monitor is connected to the RS232
serial data cable between the computer and
short haul modem. The data line monitor has
seven lights indicating the status of the RS232
serial communication. By observing these lights
in the order given below you may be able to
determine the problems with the computer link.
Pin 6 - DSR Data Set Ready. The short
haul modem holds this line high
all the time.
Pin 20 - DTR Data Terminal Ready. The
software holds this line high.
Pin 4 - RTS Request to Send. When the
computer tries to call the
weather station, it brings the
RTS line high until the call is
answered, or until the computer
stops trying to call.
Pin 5 - CTS Clear To Send.
Pin 8 - CD Carrier Detect. Both CTS and
CD lines come high when the
calling modem receives a
signal indicating that the
weather station answered the
call. If these lines do not come
high, then the communication
cable and wiring connections
should be double checked.
Pin 2 - TD Transmit Data. When the
computer sends commands to
the weather station, the TD light
will flash on. This indicates that
the computer is transmitting out
data.
Pin 3 - RD Receive Data. The weather
station echoes back responses
to the commands that the
computer has sent. The RD
light flash as these responses
are coming in.
3.2 SENSORS
Whenever sensor failure is suspected, the
sensors can be checked with a VOM
(Volt/Ohm meter) to measure for open
circuits (Section 3.2.1), or the CR10KD
(Keyboard Display) can be connected to the
CR10 to check sensor reading values
(Section 3.3.1 & Table 2.1).
3.2.1 OHM METER TESTS OF SENSORS
All sensors that are to be checked, EXCEPT for
the rain gage, should have a measurable
resistance. INFINITE resistance indicates an
open circuit. A sensor with an open circuit
should be sent in for repair.
The sensors which can be checked with an ohm
meter are:
•
Anemometer (Wind Speed)
•
Wind Direction Indicator
•
Pyranometer (Solar Radiation)
•
Rain Gage
•
Temperature
NOTE: The measurable resistance of each
sensor is NOT intended to determine the
accuracy of the sensor.
For Ohm meter tests of the sensors refer to
sensor schematics in the appendix section.
Wind Speed
Check coil resistance between the black and
clear wires for an OPEN circuit. The coil
resistance should measure between 1200 to
1300 Ohms.
Shorts to Ground - Check the base of the
sensor for moisture, or for any wires that may
have been pinched and exposed.
Wind Direction
The wind direction sensor varies its resistance
as the vane turns. With the Ohm meter
connected to the black and red wires, the
resistance should change from 1K Ohms to 11K
Ohms with a five degree open or dead band.
If infinite resistance is measured, the sensor
needs to be repaired.
With the Ohm meter connected to the black and
white wires, the resistance should read 10K
Ohms. If infinite resistance is measured, then
the potentiometer is bad and should be
replaced.
Solar Radiation
The Solar Radiation Sensor should measure
between 60 Ohms and 100 Ohms. An open
circuit should be the main thing to look for.