Chapter 7 _____________________________________________________________ Technical Data
VAISALA _______________________________________________________________________ 185
Leaf Wetness Sensor
Table 60
QLW101 Leaf Wetness Sensor Specifications
Property
Description/Value
Sensor Type
Artificial leaf electrical resistance
Excitation
Bipolar (5V nominal) built-in
Time Constant
1)
2 seconds
Current Output
Variable resistance:>1MOhm (dry) to
<130KOhm (wet)
Supply Voltage
1mA (typical) at +5 VDC ±10%
Sensor Area
28 cm
2
Attached Cable Length
5 m
Cable Type
2-twisted pair, 24 AWG shielded cable with
UV-resistant jacket, wires stripped and
tinned
Recommended Max Cable
Length
1)
24 AWG Cable (3-
conductor)
22 AWG 2-Twisted Pair
Cable
18 AWG Cable (3-
conductor)
91 m
194 m
218 m
Substrate material
Grid material
Mounting Bracket
Glass-reinforced, ceramic-filled laminate
1 oz. copper, nickel, and 50 µin gold plate
White powder-coated aluminum
Dimensions (H x W x T)
51 mm x 38 mm x 6 mm
Weight
227 g
1) Increasing the cable length above the recommended maximum cable length causes
measurement error in the form of lower moisture readings.
Fuel Moisture Sensor
Table 61
QFM101 Fuel Moisture Sensor Specifications
Property
Description/Value
Fuel moisture sensing
element
Dry ponderosa pine dowel with imbedded
wire electrodes
Fuel moisture measurement
principal
Capacitance of wood calibrated to read
percentage of moisture by weight.
Fuel moisture measurement
accuracy
0 ... 12 %FM
1)
: ±1.9 %FM RMSE
2)
(two-
week period)
12 ... 30 %FM: ±3.6 %FM RMSE
>30 %FM: ±16 %FM RMSE
Temperature sensor
Single thermistor
Conversion table range
-50 °C ... +50 °C
Temperature measurement
accuracy
±0.2°C, from -20 °C to +80 °C
Size
Base diameter 28.6 mm
Over-all length 305 mm
Weight
125 g
1) %FM = measured fuel moisture units
2) RMSE = Root Mean Square Error
