Xylem DH-21 - Manual (Page 28)

3-10 Using the “W ATER LOG” Software
DH-21
Hyper Divisor: The Hyper Divisor is used to determine the faster scan rate. The faster scan rate
is calculated by taking the regular scan rate and dividing it by the hyper divisor.
The hyper divisor must be able to be divided into the regular scan rate without a
remainder or it will default to 1. For example, if the regular scan rate is 1
minute, the following hyper divisors are valid:
SCAN RATE HYPER DIVISOR FAST SCAN RATE
1 minute 60 1 seconds
1 minute 30 2 seconds
1 minute 20 3 seconds
1 minute 15 4 seconds
1 minute 12 5 seconds
1 minute 10 6 seconds
1 minute 6 10 seconds
1 minute 5 12 seconds
1 minute 4 15 seconds
1 minute 3 20 seconds
1 minute 2 30 seconds
1 minute 1 60 seconds
Here is an example of the Hyper Logging Mode.
The scan rate is set to 15 minutes, the hyper divisor is set to 15, and the hyper limit is set to 0.1
with the units assumed to be in feet. The logger is started and the first data point is logged. The
next and all future logs will compute the difference of the current log with the last log. If the
difference is less than 0.1, the next log is scheduled to happen in 15 minutes. If the difference is
greater than 0.1, the next log is scheduled to happen in 1 minute. (15 minutes/hyper divisor =
1). The sensor will stay on the 1 minute interval until the next 15 minute interval, at which time
the sensor will evaluate the current log with the log 15 minutes previous to see if it should remain
in the hyper mode or jump back to the normal scan rate.
This option allows the sensor to capture and record quick changing data without the expense of
battery life by adjusting the scan rate based on the data change rate.
It is important for you to realize that the faster scan rate will not start until the sensor determines
a change has taken place between the last scan and the present scan. For instance, in our example
the time between last and present scans was 15 minutes. Therefore, some of the event you are
trying to track may be missed. Thus you need to determine what scan intervals are best suited for
the dynamics of the intended application.
Again, note that this check is on the level parameter only, not the temperature, and the value
entered will be in the same units as set in the coefficients options. For example, if the
coefficients units are set to read out in feet, the hyper limit will also be in feet.