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in_hypalm_aw1_v3.doc
the deep sample holder (WP-40) for products in bulk (large chunks).
The disposable sample cups serve two purposes:
(a) provide a means storing product samples prior to measurements so that they can come to
the same temperature as the probe
(b) prevent contamination across samples.
Prior to measurements, fill a number of disposable sample cup with the products to be measured.
Usually, filling up to 1/3 of the cup is sufficient.
To avoid soiling the probe, do not fill the cup
above the fill line (see below).
2. Other basic guidelines
To ensure accurate and repeatable results, please follow these basic guidelines:
a) Measure water activity only in a temperature stable area. This is an essential requirement! Do
not measure on a bench that is located near a heater, an AC vent or an open window. Avoid
direct exposure of the probe and/or product samples to sun light (heating effect). For best
accuracy, temperature should not change by more than 0.01
q
C / minute (0.0075
q
C / minute in
the case of product with a water activity > 0.80 aw)
b) Prior to measurements, place each product sample in a disposable sample cup with the cover
on. Place the cups in the same general area as the probe. Allow for sufficient time for the
samples to come to the temperature of the probe (usually room temperature). A frequent mistake
is to measure product samples which have been kept overnight in a refrigerator without first
allowing them to come to room temperature. Another mistake is to measure hot samples coming
straight from the manufacturing process. To measure water activity at a temperature other than
room temperature, place both the probe and the product samples in an incubator set at the
desired temperature.
c) Avoid warming up the probe, the sample holder or the product sample by touching or holding
for too long in your hand.
d) When using either the AW-DIO or the AwVC-DIO probe, check that the probe is on (this is the
default when powering up the HygroPalm AW1). When the probe is on, the red LED on the top of
the probe should be flashing. The probe does not operate and the HygroPalm AW1 does not get
any signal when the LED is not on. If necessary, press once on the red button located on top of
the probe.
