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Light
(OWL)
Description:
The light sensor consists of a
printed circuit board (PCB) with a DS2423 IC to measure frequency
from a Taos
TSL230BR light sensor. This is mounted inside a water proof
plastic junction box with the light sensor mounted in the cover
with glass window. This sensor can be used for indoor or outdoor
light measurements. For the weather station the OWL is mounted
to the cross arm to measure solar radiation.
To make your wiring connection, you may
remove the 4 corner screws to remove the lid. Connect your 1-wire
cable to the four position connector CN1 (Figure
3).
OWconfig:
The "Type" must be 2 and the "Mode"
must be "Separate power".
Modbus Register
Information:
The OWL has two Modbus registers
and the light sensor reading is in the second register. You
must use the "Counter" instruction in the frequency measurement
mode and select a frequency measurement period of 5 seconds
for outdoor or bright lighting. If lower light levels are encountered,
measurement periods of 10 or 20 seconds my give better resolution.
The frequency will be in the range of 0 to 12,000 Hz for light
intensity in the range of 0 to 1200 W/M2. Therefore, divide
the frequency by 10 to get Watts per Square Meter.
Specifications:
| Parameter |
Specification |
| Temperature Range |
-25 to +70C (-13 to +158F) |
| Range |
0-1200 Watts per Square Meter
(Frequency 0-12000Hz) |
| Accuracy |
+/-5% |
TSL230BR Pin
Connections:
| Pin Number |
Connection |
| 1 (S0) |
5V |
| 2 (S1) |
Common |
| 3 (OE/) |
Common |
| 4 (GND) |
Common |
| 5 (Power VDD) |
5V |
| 6 (Frequency out) |
To counter channel 2 |
| 7 (S2) |
5V |
| 8 (S3) |
5V |
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