Campbell Scientific TD Operating System Addendum for CR510, CR10X, and CR23X User Manual
Page 33
TD ADDENDUM—SECTION 8. PROCESSING AND PROGRAM CONTROL EXAMPLES
AD-8-3
03:
P92
If time is
01:
0
seconds into a
02:
900
second interval
03:
11
Set high Flag 1
04:
P84
Data Table
01:
0
Seconds into interval
02:
-1
When flag 1 is high
03:
-2
Records (0=auto; -=redirect)
05:
P72
Totalize
01:
1
Rep
02:
1
Loc Rain_mm
06:
P89
If X<=>F
01:
2
X Loc TOT_15min
02:
1
=
03:
0
F
04:
21
Set low Flag 1
07:
P84
Data Table
01:
0
Seconds into interval
02:
-1
When flag 1 is high
03:
0
Records (0=auto; -=redirect)
08:
P70
Sample
01:
1
Reps
02:
2
Loc TOT_15min
09:
P
End Table 1
8.3 USING CONTROL PORTS AND
LOOP TO RUN AM416 MULTIPLEXER
This example uses an AM416 to measure 16
copper-constantan thermocouples and 16
Model 223 soil moisture blocks. The sensors
are read every ten minutes and the average
value output once an hour. The multiplexer is
housed in an AM-ENCT enclosure to minimize
thermocouple errors created by thermal
gradients. A 107 Temperature Probe is
centrally located on the multiplexer board and
used as a thermocouple temp. reference.
The AM416 switches the 223 moisture block
out of the circuit when it is not being measured.
This eliminates the need for the blocking
capacitors used in the model 227 Soil Moisture
Block. The 223 blocks are about one fifth the
cost of the 227 blocks.
Control ports are used to reset the AM416 and
clock it through its channels. The program
sequence is:
Measure the 107 probe located at the
AM416 for TC temperature reference.
CR10 sets the port high which resets the AM416.
A loop is entered; within each pass:
The port clocking the AM416 is pulsed.
The connected TCs and moisture blocks
are measured.
CR10 sets the port controlling AM416 reset low.
Soil moisture measurements are converted
to block resistances.
The input location in which the temperature and
soil moisture measurements are stored is indexed
to the loop counter (Instruction 87, Section 12). An
indexed location is incremented by one with each
pass through the loop. For example, on the first
pass temperature is stored in Location 2, and soil
moisture in Location 18. On the second pass
temperature is stored in Location 3, and soil
moisture in Location 18. After 16 loop passes,
temperature and soil moisture measurements
occupy Locations 2 through 17 and 18 through 33,
respectively. Connections are shown in Figure
8.3-1.