Campbell Scientific CR23X Micrologger - Manual (Page 92)

SECTION 7. MEASUREMENT PROGRAMMING EXAMPLES
7-4
The temperature of the 107 Probe is stored in
input location 1 and the thermocouple
temperatures in Locations 2-6.
PROGRAM
1: Temp (107) (P11)
1: 1 Reps
2: 1 SE Channel
3: 1 Excite w/E1+reps
4: 1 Loc [ REF_TEMP ]
5: 1.0 Mult
6: 0 Offset
2: Thermocouple Temp (DIFF) (P14)
1: 5 Reps
2: 21 10 mV, 60 Hz Reject, Slow
Range
3: 1 DIFF Channel
4: 1 Type T (Copper-Constantan)
5: 1 Ref Temp (Deg. C) Loc [
REF_TEMP ]
6: 2 Loc [ TC_1 ]
7: 1.0 Mult
8: 0.0 Offset
7.5 107 TEMPERATURE PROBE
Instruction 11 is designed to excite and measure
the Campbell Scientific 107 Thermistor Probe
(or the thermistor portion of the 207 temperature
and relative humidity probe) and convert the
measurement into temperature (
o C). In this
example, temperatures are obtained from three
107 probes. The measurements are made on
single-ended channels 1-3, and the
temperatures are stored in input locations 1-3.
CONNECTIONS
The black leads from the probes go to excitation
channel 1, the purple and clear leads go to a
channel, and the red leads go to single- ended
channels 1, 2, and 3 (high and low sides of
differential channel 1 and high side of 2).
PROGRAM
1: Temp (107) (P11)
1: 3 Reps
2: 1 SE Channel
3: 1 Excite all reps w/E1
4: 1 Loc [ TEMP_1 ]
5: 1.0 Mult
6: 0.0 Offset
7.6 ANEMOMETER WITH
PHOTOCHOPPER OUTPUT
An anemometer with a photochopper transducer
produces a pulsed output which is monitored
with the Pulse Count Instruction, configured for
High Frequency Pulses. The anemometer used
in this example is the R.M. Young Model No.
12102D Cup Anemometer which has a 10
window chopper wheel. The photochopper
circuitry is powered from the CR23X 12V supply.
Supplemental charging, AC or solar, should be
used with the CR23X. If a charging source is not
practical, back-up batteries should be used to
compensate for the increased current drain.
Wind speed is desired in meters per second.
There is a pulse each time a window in the
chopper wheel, which revolves with the cups,
allows light to pass from the source to the
photoreceptor. Because there are 10 windows
in the chopper wheel, there are 10 pulses per
revolution. Thus, 1 rpm is equal to 10 pulses
per 60 seconds (1 minute) or 6 rpm = 1 pulse
per second. The manufacturer's calibration for
relating wind speed to rpm is:
Wind speed (m/s) =
0.01632 m/s/rpm x rpm + 0.2 m/s
Pulse count instruction has the option of
converting counts to frequency in Hz
(counts/second). The multiplier and offset to
convert Hz to meters per second are:
m/s =
0.01632 m/s/rpm x 6 rpm/Hz x XHz + 0.2 m/s
= 0.0979 m/s/Hz x XHz + 0.2 m/s
CR23X
FIGURE 7.6-1. Wiring Diagram for
Anemometer