Thermo Scientific Orion Versa Star VSTAR-PH, Справочное руководство

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11
Thermo Scientific Orion V
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pH with LogR Temperature Module
Chapter 5 Temperature Calibration
For improved temperature accuracy, the Orion V
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meter and pH with LogR Temperature module system offers
the option for temperature calibration. One point can be calibrated for an Automatic Temperature Compensation (ATC)
probe. Up to three points can be calibrated when LogR temperature input is being used. Please review the information
below prior to calibration.
LogR Temperature Calibration Information
This procedure should be performed at least once per week to ensure accurate temperature compensation when
operating in the LogR mode. If the meter is powered down or the electrode is disconnected, the LogR temperature
should be recalibrated. When using the meter for the first time or restarting the meter in the LogR mode, a LogR
temperature calibration must be performed. It is recommended that at least a two-point temperature calibration be
performed to meet optimum system accuracy. Up to three points can be calibrated. Refer to the
Appendix B for
additional information.
Choose a temperature calibration range that is at least 5 ºC apart, depending on your expected operating range.
Evenly bracket your expected sample temperature range. A maximum 20 ºC range is recommended for maximum
accuracy. For example, for measurements around 20 ºC, calibrate at 10 ºC and 30 ºC. For a temperature span greater
than 20 ºC, a three-point temperature calibration is recommended. For many samples, a single-point calibration near the
expected sample temperature will yield adequate results. A constant temperature bath or a hot plate is recommended
to hold the temperature of calibrating solution.
For best results during temperature calibration, it is recommended that a pH buffer or tap water be used as
the temperature calibrating solution. Do not use distilled water because the conductivity is too low to obtain a
good calibration.
LogR Calibration Technique
LogR calibration can be done by using an ATC probe or with a NIST reference. An accurate and the fastest method is to
use an ATC probe. The most accurate method is to use a NIST reference, such as a NIST-traceable thermometer.
Note: The meter defaults to using an ATC probe for LogR calibration. If the temperature reading for the ATC probe
requires adjustment, follow the instructions for ATC probe calibration technique in the next section.
1. In the measurement mode, press setup/3 key.
2. Use the
arrow
keys to highlight the pH channel with LogR and press
f3 (Select)
.
3. Press the right arrow key to highlight Temperature, and press f3 (Select) .
4. Temperature Input should be set to LogR. Use the arrow keys to highlight the appropriate LogR
temperature channel if LogR is not already selected. Select the appropriate channel with LogR for
Temperature Cal and press f3 (Select) .