Sensor Calibration - Novasina LabTouch-aw Operating Instructions Manual

8.

Sensor Calibration

How to Handle SAL-T Standards Correctly
8.1
stable protocol" is set to "Off".
• Transmittance to the Novalog MC software can be done by selecting "PC" or
"SD+PC". This way, a automatic print-out of the protocol on any connected
PC printer (incl. pdf) can be achieved . "PC" or "SD+PC" are only displayed
if the the instrument has been licensed for NovalogMC.
Manual saving of a protocol
• A protocol of the current values ("Actual protocol") can be saved anytime
and even during an on-going measurement on the SD-card by pressing the
printer symbol on the main menu screen. Just select "Actual to SD-Card"
on the appearing pop-up window.
• A "Stable protocol" can only be stored this way, if stable values are present,
respectively if a measurement value had been considered as stable. If these
pre-requisites are fulfilled, a pop-up appears after pressing the print button
and you have to select "Stable to SD-card" to initiate the saving process.
• The protocols can be transfered directly to a PC if the instrument has been
recognized by the optional NovalogMC software by selecting "Actual to PC"
respectively "Stable to PC" after pressing the printer symbol
• "Actual to PC" and "Stable to PC" are not displayed without a connection
to NovalogMC
The electrolytic sensor can be verified at any time by using the Novasina SAL-T
standards which are included in the delivery or which have been bought through
the local Novasina distributor. These reusable standards generate defined and
reproducible humidity, respectively aw-values. If verification fails, a calibration
can be performed in an easy way.
Note:The calibration values will be stored in a small memory located on the
sensor board. It is not required that a calibration is performed at all available
calibration points. Perform a two-point calibration with one point below and one
above of the normal measurement range (bracket calibration).
For example: Your samples are always around 0.700aw. It is sufficient if you
use the 58%rH and the 75.%rH SAL-T standards for calibration. If verification
is requested, calibrate at 58%rH and 84% rH and use the 75%rH SAL-T stan-
dards for verification.
The Novasina SAL-T standards are not labeled with a due date. The shelf-life
itself depends on the handling and storage conditions. Experiences in the field
have proven that those standards can be good for 3-5 years if handled correctly.
To achieve the best possible shelf-life, please
• Shake all SAL-T standards twice a month for one minute, nevertheless if
you have used them or not. There is no need to take it out of the plastic
container.
• Always store the standards in the plastic container (close tightly) and not
exposed to direct sunlight.
• Do not expose the salt tablet to environmental air for longer than necessa-
ry; thus, put it back if calibration has been finished at the particular point.
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