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SECTION 3. PROGRAMMING
Sensor
Temperature
Relative Humidity
Solar Radiation
Wind Speed
Wind Direction
Rain
Moisture Index
S = Single Ended Analog Channel
D = Differential Analog Channel
3.1.1. TEMPERATURE AND RELATIVE
HUMIDITY
The thermistor is read using Instruction 11.
The RH sensor is read using Instructions 20
and 4. Instruction 20 switches 12 V to the RH
sensor; Instruction 4 delays 80 ms then makes
the measurement. Instruction 20 is used again
to switch the 12 V off. Instructions 37 and 34
convert the temperature to degrees F and put it
into location 5.
03:
P11
01:
1
02:
1
03:
1
04:
4
05:
1
06:
0
04:
P37
01:
4
02:
1.8
03:
5
05:
P34
01:
5
02:
32
03:
5
06:
P20
01: 0000
02: 1000
07:
P4
01:
1
02:
5
03:
7
04:
2
3-2
TABLE 3-2. Parameters for Sensor Measurement Instruction
Instr.
Measurement
No.
AC Half Bridge
11
DC Half Bridge
4
Diff. Voltage
2
Frequency
3
(AC Magnetic)
Half Bridge
4
Contact Closure
3
AC Half Bridge
5
Temp 107 Probe
Rep
IN Chan
Excite all reps w/EXchan 1
Loc [:temp C ]
Mult
Offset
Z=X*F
X Loc temp C
F
Z Loc [:temp F ]
Z=X+F
X Loc temp F
F
Z Loc [:temp F ]
Set Port(s)
C8..C5=low/low/low/low
C4..C1=high/low/low/low
Excite,Delay,Volt(SE)
Rep
2500 mV slow Range
IN Chan
Excite all reps w/EXchan 2
Input
Input
Ch.
Code
1S
N/A
4S
5
3D
2
1
N/A
3S
5
2
N/A
12S
13
05:
80
06: 0000
07:
6
08:
.1
09:
0
08:
P20
01: 0000
02: 0000
3.1.2 WIND SPEED
The wind speed sensor is read by pulse count
Instruction 3, programmed for low level AC and
to measure frequency. The relationship
between wind speed, ws, and frequency, f, for
the R.M. Young Wind Sentry is:
ws = 1.677f + 0.4
where ws has units of mph and f is in Hz. The
result is placed in location 8. If the result equals
the anemometer offset (0.4 mph), the wind
speed value is set to 0; i.e., when there is no
wind speed the offset is not used in the wind
vector calculations.
10:
P3
01:
1
02:
1
03:
21
04:
8
05:
1.677
06:
.4
11:
P89
01:
8
02:
1
03: .
4
04:
30
Range
Excit
mV
Ch
mV
N/A
1
2000
2500
2
0000
7.5
N/A
N/A
N/A
N/A
N/A
2500
2
2500
N/A
N/A
N/A
25
3
2500
Delay (units .01sec)
mV Excitation
Loc [:RH
]
Mult
Offset
Set Port(s)
C8..C5=low/low/low/low
C4..C1=low/low/low/low
Pulse
Rep
Pulse Input Chan
Low level AC; Output Hz.
Loc [:WS mph ]
Mult
Offset
If X<=>F
X Loc WS mph
=
F
Then Do
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