CR10X User Guide
8-16
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 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 *6D 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 50psi Druck 930/ti with a calibration of 49.93mV/10V of excita-
tion or 4.993mV/V (at 50psi). Your calibration will be different. An excitation
voltage of 1500mV yields a maximum signal of 7.489mV at 50psi, fully utilising
the 7.5mV input range to provide the best resolution.
The multiplier, m, is calculated to provide depth of water in metres:
m = (50psi/4.993 mV/V) * (0.703m/psi)
m = 7.04m/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. The offset equals the initial distance of
14.4m (47.23 feet) plus the initial reading of 16.69m (54.77 feet), or 31.09m (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
