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SECTION 8. PROCESSING AND PROGRAM CONTROL EXAMPLES
8-10
17: P94 Else
18: P34 Z=X+F
01: 2 X Loc DOWN CNT
02: -1 F
03: 2 Z Loc [:DOWN CNT ]
19: P95 End
20: P End Table 1
* A Mode 10 Memory
Allocation
01: 28 Input Locations
02: 64 Intermediate Locations
03: 84 Final Storage Area 2
8.9 LOGARITHMIC SAMPLING USING
LOOPS
A ground water pump test requires that water
level be measured and recorded according to
the following schedule.
Output Interval
Time into Test, min Loop #
00 to 10 10 sec. 1
10 to 30 30 sec. 2
30 to 100 1 min. 3
100 to 300 2 min. 4
300 to 1000 5 min. 5
1000 and greater 10 min. 6
This is accomplished with a series of loops
(Instruction 87), where the delay and count
parameters are used to implement the
frequency of measurement (and output) and the
duration of the that frequency. The unit of
delay is the execution interval. A delay of 1
with a 10 second execution interval and a count
of 60 means the instructions in the loop, in this
case measure and output water level, are
executed every 10 seconds for 10 minutes.
The drawdown portion of the test is completed
at some time greater than 1000 minutes. To
enter the recharge phase of the test, the
operator enters the *6AD Mode and sets Flag 1
high. At the next 10 minute pass through loop
6 the loop is exited. Program execution returns
to the top of the program table and the
measurement schedule starts over again for the
recharge test.
The sensor is a 50 PSI Druck, model 930/ti with
a calibration of 49.93 mV/10V of excitation or
4.993mV/V. Your calibration will be different.
An excitation voltage of 1500 mV yields a
maximum signal of 7.489 mV at 50 PSI, fully
utilizing the 7.5 mV Input Range to provide the
best resolution.
The multiplier, m, is calculated to provide depth
of water in feet:
m = (50 psi/4.993 mV/V) * (2.3067 ft/psi)
m = 23.099 ft/mV/V
The offset is calculated to provide a final value
that represents the distance from the lip of the
well to the water surface. Similar to Figure
7.16-2, the offset equals the initial distance of
47.23 feet plus the initial reading of 54.77, or
102 feet.
* 1 Table 1 Programs
01: 10 Sec. Execution Interval
User must toggle flag 1 to start measurements
01: P91 If Flag/Port
01: 21 Do if flag 1 is low
02: 0 Go to end of program table
Loop 1, Output every 10 seconds for 10 minutes
02: P87 Beginning of Loop
01: 1 Delay
02: 60 Loop Count
03: P86 Do
01: 1 Call Subroutine 1
04: P95 End
Loop 2, Output every 30 seconds for 20 minutes
05: P87 Beginning of Loop
01: 3 Delay
02: 40 Loop Count
06: P86 Do
01: 1 Call Subroutine 1
07: P95 End
Loop 3, Output every 1 minute for 70 minutes
08: P87 Beginning of Loop
01: 6 Delay
02: 70 Loop Count
09: P86 Do