X p l o r e r G L X U s e r s ’ G u i d e
75
Because they are not needed, the fields for Pt 1 are hidden when the 1 Point
Slope calibration type is selected, and the fields for Pt 2 are hidden when the
1 Point Offset calibration type is selected.
Calibrated Output and Raw Input
Two live values are displayed at the bot-
tom of the Calibration dialog box: the Calibrated Output Measurement and the
Raw Input Measurement. The Raw Input Measurement is the data transferred
from the sensor to the GLX. The Calibrated Output Measurement is the value
resulting from the currently defined calibration. The Calibrated Output Measure-
ment is displayed in the Graph, Table, and other displays.
Note About Raw Input Measurement
The value and units of the raw input measurement data can be confusing because
they do not necessarily have an obvious meaning. Depending on which sensor
you are using, the raw input may represent the default calibration, the voltage
produced by an electrode in the sensor, or the digital output of the sensor’s ana-
log-to-digital converter.
Keep in mind that it does not matter what the value is, or what its units are. It is
only important that the raw sensor input varies in direct proportion to the quantity
being measured.
Calibration Procedures
If you don’t know whether a two-point or one-point slope calibration is best
suited for a particular sensor, follow steps 1–3 of either procedure and
observe the Calibration Type that is automatically selected.
Two-Point Calibration Procedure
A two-point calibration requires two known standards. For instance, if you are
calibrating a pH sensor, you might use two buffer solutions: one of pH 4 and the
other of pH 7.
The fields of the Calibration dialog box are identified on page 74.
1.
From the Sensor field, select the desired sensor.
2.
From the Measurement field, select the desired measurement.
3.
Set the Single/All field to “Calibrate selected measurement only.”
4.
From the Calibration Type menu, select 2 Point, if it is not already selected.
5.
Place the probe in the first known standard.
6.
Enter the value of the standard in the Standard Value field for Pt 1.
7.
Observe the Raw Input Measurement displayed near the bottom right corner
of the screen and wait until it has stabilized.
Calibrated Output
Measurement
Raw Input
Measurement
Live Data
Press to copy Raw
Input Measurement to Pt 1
Sensor Input Value
F3
Enter standard
value here
Summary of Contents for Xplorer GLX
Page 4: ......
Page 6: ......
Page 7: ...Part 1 Users Guide...
Page 8: ......
Page 18: ...12 O v e r v i e w o f t h e G L X...
Page 94: ...88 S e t t i n g s S c r e e n...
Page 98: ...92 P r i n t i n g...
Page 104: ...98 O p e r a t i n g T e m p e r a t u r e...
Page 112: ......
Page 116: ...110 C a l o r i m e t r y...
Page 132: ...126 V o l t a g e v e r s u s R e s i s t a n c e...
Page 136: ...130 I n d u c e d E l e c t r o m o t i v e F o r c e...
Page 146: ...140 B e a t F r e q u e n c y...
Page 150: ......
Page 152: ......
