CR10X User Guide
8-18
02:
P6
Full Bridge
01:
1
Rep
02:
32
7.5mV 50Hz rejection Range
03:
1
IN Chan
04:
1
Excite all reps w/EXchan 1
05:
1500
mV Excitation
06:
1
Loc [:LEVEL M]
07:
7.04
Mult
08:
31.09
Offset
03:
P86
Do
01:
10
Set high Flag 0 (output)
04:
P77
Real Time
01:
111
Day,Hour-Minute,Seconds
05:
P70
Sample
01:
1
Reps
02:
1
Loc LEVEL M
06:
P95
End
07:
P
End Table 3
8.10 Covariance/Correlation Programming Example
The example is a 2-level meteorological tower with five sensors at each level. The
three components of the wind are measured using propeller anemometers. Two
thermocouples (TC) are used to measure ambient and wet-bulb temperatures and
calculate water vapour pressure on-line. All sensors are scanned once per second
(1Hz) and a 5-minute subinterval averaging period with a 30-minute Output
Interval is specified. The example optimises the input measurement sequence for
speed and shows the instructions necessary to provide calibrated inputs, properly
ordered to produce the desired outputs from the Covariance Correlation
(COV/CORR) instruction. Table 8-1 groups the sensors according to
measurement type and gives the CR10X multiplier and offset.
Table 8-1 Example Sensor Description and CR10X Multiplier and Offset
Description
Symbol
Sensor Calibration
Meas. Type
Multiplier Offset
Horiz. Wind
U
propeller
18m/s/V
S.E.V.
.018m/s/V 0.0
Horiz. Wind
V
propeller
18m/s/V
S.E.V.
.018m/s/V 0.0
Vert. Wind
W
propeller
22m/s/V
S.E.V.
.022m/s/V 0.0
Air Temp.
Ta
TC
-
TC DIFF.
1.0
o
C
0.0
Wet-bulb Temp.
Tw
TC
-
TC DIFF.
1.0
o
C
0.0
Vapour Presure
e
derived
-
-
-
-
The outputs of the propeller anemometers can all be measured as single-ended
voltages. The vertical wind propeller calibration differs from the U and V propeller
calibration. The fastest input sequence is to measure both levels (six propellers)
with a single instruction using the U and V calibration and correct the W
measurements with Fixed Multiply, Instruction 37.
An AM25T Solid State Thermocouple Multiplexer is used to measure the output of
the four Type E thermocouples. The AM25T has a built-in 1000 ohm PRT that is
used as a reference temperature for the thermocouples. The thermocouples are
measured on the most sensitive input range, 2.5mV, accommodating a
±
40
o
C
range between the measurement and AM25T TC reference junction. The resolution