In-Situ TROLL 9500 Operators Manual - Manual (Page 25)

18
0095110 rev. 007 01/09 TROLL 9500 Operator’s Manual
The Quick Calibration Wizard starts. A screen like this is displayed.
7. Insure there is a check beside the sensors you wish to Quick-Cal.
8. Click Next. The pH, ORP, and Conductivity screen appears.
9. Click Run to start the calibration.
The display will continuously update as readings are taken and
compared against the stabilization criteria (see sidebar).
All 3 parameters must indicate NOMINAL or STABLE before the
calibration can continue.
s
D.O. calibration screen is displayed automatically if a polaro-
graphic D.O. sensor is installed.
SECTION 3: GETTING STARTED
Q:
A:
What is the difference between NOMINAL and STABLE?
To meet the criteria for a valid calibration point, the change
(deviation) in sensor response is monitored over time. The
software is looking for the calibration solution temperature
and the sensor readings to settle over a specific time period.
The criteria for STABLE are designed to meet the published
specifications. The NOMINAL criteria are designed to
shorten the calibration time when an approximate calibration
is acceptable. When the deviation falls within the limits of
the “loosened” specifications, NOMINAL is displayed in the
Status area, and the Accept button becomes available to
store the current calibration point.
Accepting a NOMINAL value may save considerable time.
In some cases, especially if the sensors have been soaking
in the solution for several minutes prior to calibration, the
accuracy achieved by accepting a nominal value may be
very similar to that obtained by waiting for complete stability.
7
8
9
Status indicators during stabilization:
NOT TESTED may be displayed before the calibration begins.
UNSTABLE indicates the sensor response does not meet the
criteria for a valid calibration point. All parameters start out at
“Unstable” status.
NOMINAL indicates the change in the sensor response over
time meets a relaxed stability criterion. “Nominal” stability will
occur first, and can be accepted to shorten the calibration time.
STABLE indicates the change in the sensor response over time
meets the stability criteria for a Quick Cal.
Reading: Current sensor response (in indicated units).
Deviation: Change in response between the last two readings.
This enables you to follow the progress of the stabilization, but
deviation from the previous reading is not necessarily the best
indicator of stability as the software is looking at longer-term
trends.
Run button: Starts the calibration
Accept button: Becomes available when Nominal stability is
reached (see below)
Stop button: Stops the current phase of the calibration
Back button: Goes to the previous screen (when available)
Next button: Proceeds to the next screen (when available)
Cancel button: Cancels the calibration