Instruction manual

5-1
SECTION 5. TROUBLESHOOTING
This section offers some solutions to common problems. All the locations and data values are based on
the example program in Section 3.
5.1 SYMPTOMS, PROBLEMS, AND
SOLUTIONS
1. Symptom: The temperature is a constant
value of 17, with the fractional portion randomly
fluctuating.
Problem: The 127 fine wire thermocouple is
broken or not installed.
Solution: Replace or install the 127.
2. Symptom: Signal response on the 127 is
down. Input location 2 data is fluctuating slowly.
Problem: Debris is caught up in the fine wire
thermocouple junction, e.g. a spider web.
Solution: Carefully blow away the debris with a
can of compressed air. Do not direct the air
stream at the thermocouple junction because
the junction is extremely fragile. Rather, put the
junction on the peripheral of the air stream.
3. Symptom: The vertical wind is fluctuating only
in the hundredths place. When the transducers
are blown on, the CA27 does not respond with
reasonable values.
Problem: One or more transducers are
missing or the transducer pins have been
damaged.
Solution: Replace the transducers, see
Appendix B for removal and installation
procedures.
4. Symptom: Vertical wind speed is a near
steady positive or negative value.
Problem: A transducer is shorted. The
transducers will short if they are twisted on the
mounting arms (see Appendix B for proper
removal procedure) or if they become wet.
When the transducers are shorted, the CA27
outputs a near constant voltage. If the lower
transducer is shortened, the CA27 will output a
negative value. If the upper transducer is
shorted, the CA12 will output a positive value.
Solution: Allow the transducers several hours
to dry. Then check the CA27 zero offset with a
zero velocity anechoic chamber (see Appendix
C). After checking the zero offset, check the
CA27 by blowing on the lower and upper arms
of the CA27. The 21X should measure a
negative and positive wind speed respectively.
5. Symptom: The vertical wind fluctuations are
not equally distributed around zero.
Problem: Zero offset has drifted.
Solution: Send the CA27 back to the factory
for adjustment or see Appendix C for the zero
offset adjustment procedures.
6. Symptom: The krypton hygrometer voltage is
-99999.
Problem: This problem occurs in extremely
arid environments. The hygrometer is
outputting signal greater than 5 Volts to the
21X. The 21X can only measure voltages
between ± 5 Volts.
Solution: Send the KH20 back to the factory to
have its path length widened or use a voltage
divider to reduce in the input signal.
7. Symptom: KH20 has power, but it is not
outputting a signal. The “blue glow” from the
source tube (the larger of the two tubes) is not
visible. The glow is only visible under low or no
light conditions.
CAUTION: Never look directly into the
KH20 source tube (the longer of the two
tubes). To see the “blue glow”, insert a
piece of paper between the tubes, under
low light conditions, and look at the paper.
When an Ammeter is placed serially in the
power line (positive of Ammeter to positive of
battery, negative of Ammeter to positive of
KH20, and negative of KH20 to negative of
battery), the current drain is not in the range of
10 to 20 mA.
Problem: KH20 tubes have blown out.
Solution: Return the KH20 to have the krypton
tubes replaced.