TDR SOIL MOISTURE MEASUREMENTS
10
6.3 EXAMPLE 3, TDR MEASUREMENTS IN
TABLE 2 WITH ANALOG MEASUREMENTS
IN TABLE 1
This example is for 4 multiplexers. The level 1
multiplexer has a multiplexer connected to each
of channels 1, 2, and 3 and probes connected
to channels 4 through 8. The second level
multiplexers each have 8 probes. The
measurements are made every 30 minutes and
the averages are output every 4 hours.
Placing the TDR measurements in Table 2
allows analog measurements to be made in
Table 1. The analog measurements will
continue to be made during TDR
measurements because Table 1 can interrupt
Table 2.
The interruption cannot take place if the output
flag is set in Table 2. Note that Instruction 92 is
used to set flag 1 every 4 hours prior to making
the TDR measurements. After making the
measurements, flag 1 is checked to see if it is
time for output.
*
1
Table 1 Programs
01:
10
Sec. Execution Interval
Table 1 contains the program for making analog
measurements; for example, a meteorological
station or a number of soil temperatures. The
measurements in Table 1 will be made at their
scheduled interval even while the TDR
measurements are made in Table 2 because
Table 1 can interrupt Table 2.
01:
P
End Table 1
*
2
Table 2 Programs
01:
60
Sec. Execution Interval
01:
P92
If time is
01:
0
minutes into a
02:
30
minute interval
03:
30
Then Do
02:
P92
If time is
01:
0
minutes into a
02:
240
minute interval
03:
11
Set high Flag 1
03:
P86
Do
01:
44
Set high Port 4
04:
P100
SDM-1502
01:
22
Address
02:
0
Moisture
03:
.3
Probe length (meters)
04:
0
Cable length (meters)
05: 4005
MMMP--Mux channels & Probes
06:
21
Loc [:MUX 1 #1 ]
07:
0.1138
Mult
08:
-.1758
Offset
05:
P100
SDM-1502
01:
22
Address
02:
0
Moisture
03:
.3
Probe length (meters)
04:
0
Cable length (meters)
05: 1108
MMMP--Mux channels & Probes
06:
26
Loc [:MUX 2-1#1]
07:
0.1138
Mult
08:
0.1758
Offset
06:
P100
SDM-1502
01:
22
Address
02:
0
Moisture
03:
.3
Probe length (meters)
04:
0
Cable length (meters)
05: 2108
MMMP--Mux channels & Probes
06:
34
Loc [:MUX 2-2#1]
07:
0.1138
Mult
08:
0.1758
Offset
07:
P100
SDM-1502
01:
22
Address
02:
0
Moisture
03:
.3
Probe length (meters)
04:
0
Cable length (meters)
05: 3108
MMMP--Mux channels & Probes
06:
42
Loc [:MUX 2-3#1]
07:
0.1138
Mult
08:
0.1758
Offset
08:
P86
Do
01:
54
Set low Port 4
09:
P91
If Flag/Port
01:
11
Do if Flag 1 is high
02:
10
Set high Flag 0 (output)
10:
P86
Do
01:
21
Set low Flag 1
11:
P77
Real Time
01:
110
Day,Hour-Minute
12:
P71
Average
01:
29
Reps
02:
21
Loc MUX 1 #1
