In-Situ TROLL 9500 Operators Manual - Manual (Page 44)

37 TROLL 9500 Operator’s Manual 0095110 rev. 007 01/09
parameter may be selected for event comparisons, and the “delta”
or difference amount is prompted in the current basic parameter
unit.
s
and lows that may occur, for example, when a water wave passes
over the instrument. Each stored measurement is the average of
several rapid measurements.
4. Measurement Interval
The interval specifies how often measurements will be taken during
this test. Enter any combination of Days, Hours, Minutes, & Seconds.
The minimum (fastest) allowable interval depends on your choice of
measurement schedule and the parameters included in the test. For
most parameters, the minimum interval is 5 seconds. If RDO Optical
Dissolved Oxygen is included, the minimum interval is 10 seconds.
5. Start Mode
Choose one of the following options for starting this test:
s
TROLL 9500 is connected to a PC by pressing the Start button.
This mode is useful when you want to synchronize the start of data
collection with an external event like starting a pump.
s
you specify. The time proposed by the software is the next hour on
the hour, calculated from the current device time plus 10 minutes.
Arrows beside the list boxes may be used to change the start time
and date, or key in the desired start time and date.
TIP: In entering the Scheduled Start time, keep in mind that
when this test starts, it will stop a running test.
The time proposed for a Scheduled start is the next hour on
the hour, calculated from the current device time plus 10
minutes. In Pocket-Situ this is your only indication of the
device time. If the proposed time is wrong, cancel test setup and set
the device clock before scheduling tests.
ENDING SETUP
After you select the test options and click Finish, the information will
be sent to the device and the new test will appear in the Navigation
tree.
To let you know which tests can be started with the Start button, the
software displays a different symbol for each start type:
Manual start test (you start)
Scheduled start test (starts by itself)
MORE ON MEASUREMENT SCHEDULES
LINEAR
In Linear sampling, all selected channels are measured at the same
Measurement Interval; all measurements are stored in memory.
EVENT
All selected parameters are measured at your chosen Measurement
Interval, but a data point (reading from all active channels) is stored
only if the measurement on the designated “event” channel exceeds a
user-defined value. This value is called “Delta” because it relates to a
change in the measurement. Here’s how it works:
Delta
Each measurement on the selected “event” channel (pressure, for
example) is compared to a reference. The initial reference is taken at
the start of the test. When a pressure measurement varies from the
reference by less than the Delta amount, the data point is not stored.
When a pressure measurement varies from the reference by more
than the Delta amount, the data point (all channel measurements) is
stored. The stored pressure measurement is called a “Delta point” and
becomes the new reference for comparison.
In an Event test, then, small and essentially insignificant changes are
not stored, but larger and more significant changes are. This scheme
will minimize the size of a data file by storing meaningful data.
SECTION 6: LOGGING DATA
Q:
A:
Where do I enter the stop time for the test?
You will not be asked for a stop time because the end of a
test cannot be programmed in advance. In most cases, the
only way to stop data collection is to connect to a PC, select
the test in the Navigation tree, and press the Stop button.
Exceptions: A test stops automatically under these conditions:
s
s
“ABEND” (ABnormal END) in the Navigation tree.
s
“ABEND” in the Navigation tree.
TIP: If you wish to schedule the end of data collection,
try this: Before starting your test, define another test to
start at the time you want the “real” test to stop. Select
a linear test with a long measurement interval—hours or days—
and minimal sensors to conserve battery power. Schedule this
test to start at the time you want the “real” test to end. The test
will start at its scheduled time, stopping the earlier test and
kicking into a sparse sampling schedule.