SECTION 8. PROCESSING AND PROGRAM CONTROL EXAMPLES

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

8.9LOGARITHMIC 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, minLoop #

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.

8-10

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

47.23feet 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