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05305L-90(J)
Initial installation is most easily performed using two people; one
to adjust instrument position and the other to observe an indicating
device. After initial installation with the included orientation ring, the
instrument can be removed and returned to its mounting without
re-alignment. Install the Wind Monitor following these steps:
1. MOUNT WIND MONITOR
a) Place orientation ring on mounting post. Do Not tighten band
clamp yet. (Orientation ring may be omitted when portable
tripod is used.)
b) Place Wind Monitor on mounting post. Do Not tighten band
clamp yet.
2. CONNECT SENSOR CABLE.
a) Connect sensor cable according to wiring diagram located at
back of manual.
3. ALIGN VANE
a) Connect instrument to indicator.
b) Choose a known wind direction reference point on the
horizon.
c) Sighting down instrument center line, point nose cone at
reference point on horizon.
d) While holding vane in position, slowly turn base until indicator
shows proper value.
e) Tighten mounting post band clamp.
f) Engage orientation ring indexing pin in notch at instrument
base.
g) Tighten orientation ring band clamp.
CALIBRATION
The Wind Monitor is fully calibrated before shipment and should
require no adjustments. Recalibration may be necessary after
some maintenance operations. Periodic calibration checks are
desirable and may be necessary where the instrument is used in
programs which require auditing of sensor performance.
Accurate wind direction calibration requires a Model 18112 Vane
Angle Bench Stand. Begin by connecting the instrument to a signal
conditioning circuit which has some method of indicating the wind
direction value. This may be a display which shows wind direction
values in angular degrees or simply a voltmeter monitoring the
output. Orient the base so the junction box faces due south.
Visually align the vane with the crossmarkings and observe the
indicator output. If the vane position and indicator do not agree
within 5°, it may be necessary to adjust the potentiometer coupling
inside the main housing. Details for making this adjustment appear
in the MAINTENANCE, POTENTIOMETER REPLACEMENT,
outline, step 7.
It is important to note that while the sensor mechanically
rotates through 360°, full scale wind direction signal from the
signal conditioning occurs at 355°. The signal conditioning
electronics must be adjusted accordingly. For example, in
a circuit where 4 to 20 mA represents 0° to 360°, the output
must be adjusted for 19.8 mA when the instrument is at 355°.
[((355°/360°) x 16 mA) + 4 mA].
Wind speed calibration is determined by propeller pitch and the
output characteristics of the transducer. Calibration formulas
showing wind speed vs. propeller rpm and output frequency are
included below. Standard accuracy is ± 0.2 m/s (0.4 mph). For
greater accuracy, the sensor must be individually calibrated in
comparison with a wind speed standard. Contact the factory or
your supplier to schedule a NIST (National Institute of Standards &
Technology) traceable wind tunnel calibration in our facility.
To calibrate wind system electronics, temporarily remove
the propeller and connect an Anemometer Drive (18802
or equivalent) to the propeller shaft. Apply the calibration
formula to the calibrating motor rpm and adjust the electronics
for the proper value. For example, with the propeller shaft
turning at 3600 rpm, adjust an indicator to display 18.4 m/s
[3600 rpm x 0.00512 (m/s)/rpm = 18.4 m/s.]
Details on checking bearing torque, which affects wind speed and
direction threshold, appear in the following section.
CALIBRATION FORMULAS
Model 05305L Wind Monitor w / 08254 Propeller
WIND SPEED vs PROPELLER RPM
m/s
=
0.00512 x rpm
knots
=
0.00995 x rpm
mph
=
0.01145 x rpm
km/h
=
0.01843 x rpm
WIND SPEED vs mA OUTPUT
m/s
=
( 6.250 x mA)-25
knots
=
(12.125 x mA)-48.5
mph
=
(13.980 x mA)-56
km/h
=
(22.500 x mA)-90
WIND DIRECTION vs mA OUTPUT
DEGREES
=
(22.5 x mA)-90
MAINTENANCE
Given proper care, the Wind Monitor should provide years of
service. The only components likely to need replacement due to
normal wear are the precision ball bearings and the wind direction
potentiometer. Only a qualified instrument technician should perform
the replacement. If service facilities are not available, return the
instrument to the company. Refer to the drawings to become familiar
with part names and locations. The asterisk * which appears in
the following outlines is a reminder that maximum torque on all
set screws is 80 oz-in.
POTENTIOMETER REPLACEMENT
The potentiometer has a life expectancy of fifty million revolutions.
As it becomes worn, the element may begin to produce noisy signals
or become non-linear. When signal noise or non-linearity becomes
unacceptable, replace the potentiometer. Refer to exploded view
drawing and proceed as follows:
1. REMOVE MAIN HOUSING
a) Unscrew nose cone from main housing. Set o-ring aside for
later use.
b) Gently push main housing latch.
c) While pushing latch, lift main housing up and remove it from
vertical shaft bearing rotor.
2. UNSOLDER TRANSDUCER WIRE
a) Remove junction box cover, exposing circuit board.
b) Remove screws holding circuit board.
c) Unsolder three potentiometer wires (white, green, black),
two wind speed coil wires (red, black), and earth ground wire
(red) from board.
3. REMOVE POTENTIOMETER
a) Loosen set screw on potentiometer coupling and remove it
from potentiometer adjust thumbwheel.
b) Loosen set screw on potentiometer adjust thumbwheel and
remove it from potentiometer shaft.
c) Loosen two set screws at base of transducer assembly and
remove assembly from vertical shaft.
d) Unscrew potentiometer housing from potentiometer
mounting & coil assembly.
e) Push potentiometer out of potentiometer mounting &
coil assembly by applying firm but gentle pressure on
potentiometer shaft. Make sure that the shaft o-ring comes
out with the potentiometer. If not, then gently push it out
from the top of the coil assembly.
