Specifications

Accuracy at 20, 40 & 0 °C
PERCENT RELATIVE HUMIDITY
ERROR, PERCENT RH
20 °C 40 °C0 °C
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
20.1 39.9 59.9 80.0 89.9 80.1 60.0 40.0 20.0
HUMICAP
®
Sensor Construction
Upper
electrode
Active thin
film polymer
Lower
electrodes
Supporting
glass substrate
RH Accuracy
and Stability:
Both are Important
When specifying an RH instru-
ment, be sure to consider both:
 Accuracy  how closely the
instrument's readings agree
with the standard to which it
was calibrated
 Stability  the instrument's
ability to maintain this same
level of accuracy over time,
i.e., accuracy that lasts!
Any manufacturer can "tweak"
an instrument to agree with a
reference at the time of calibra-
tion. It is important that you
know how long the instrument
can maintain this level of accu-
racy.
Vaisala's patented HUMICAP
®
thin-film capacitance relative
humidity sensors offer accuracy
that lasts! That is, they are the
most stable RH sensors available
today, better than 0.5 %RH/year
in normal air conditions. This
means that when you select one
of Vaisala's ±1%, 2%, or 3%
instruments, you can rely on it to
maintain this same level of RH
accuracy tomorrow, next week,
and several months from now
without recalibration.
New Transmitter
Selection Guide
(see back pocket)
And Vaisala offers the most
complete line of RH instruments:
from low cost HVAC transmitters
with interchangeable calibration-
free sensors, to hand-held and
desktop instruments, to "smart"
high performance humidity/
dewpoint transmitters. Seventeen
new products are introduced in
this catalog along with a compre-
hensive Transmitter Selection
Guide to assist you in making the
best choice.
ISO 9002 Certified
Quality System; NIST
Traceable Calibration
and Service Laboratory
Vaisala Inc. has earned ISO 9002
certification for its Quality
System. Our objective is continu-
ous improvement in the quality of
our products and services. The
practical benefits that you can see
today include:
 Products that perform to our
written specifications  open the
box and enjoy years of trouble-
free use thereafter.
 Normal delivery of 1 to 5 unit
orders within one week from
receipt of order
 Normal delivery of 6 to 10 unit
orders within two weeks from
receipt of order.
 For large orders we check and
inform you of delivery time
before we accept the order.
We then meet this delivery
time.
 NIST-traceable calibration
service to accuracy of:
±1%, 2%, and 3%.
 Five day guaranteed turn
around of units sent in for
warranty and after warranty
service/calibration.
 Priority turnaround service
also available for a modest
additional charge.
Documented
Performance
Vaisala's Calibration Laboratory
maintains traceability to NIST by
testing our transfer standards at
NIST annually. The following
NIST data documents the excep-
tional measurement performance
attainable with Vaisala products
(including calibration uncertainty,
non-repeatability, hysteresis,
non-linearity, and temperature
dependence) at three tempera-
tures, 20 °C, 40 °C and 0 °C.
Humidity Accuracy That Lasts!
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