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current values will be displayed.
4.5
Adjustment or Calibration
4.5.1
Calibration Discussion
The purpose of calibration is to fine tune or correct for any sensor error associated with the devices
margin of error. The measurement can be adjusted from the console to calibrate to a known source.
Calibration is only useful if you have a known calibrated source you can compare it against, and is
optional. This section discusses practices, procedures and sources for sensor calibration to reduce
manufacturing and degradation errors. Do not compare your readings obtained from sources such as
the internet, radio, television or newspapers. The purpose of your weather station is to measure
conditions of your surroundings, which vary significantly from location to location.
4.5.2
Indoor Humidity Calibration
To enter the indoor humidity calibration mode, press and hold the
SET
and
MIN/MAX
buttons at the
same time for 5 seconds and the indoor humidity value will begin flashing. Press the
CH/+
button to
increase the humidity and the
MIN/MAX
button to decrease the humidity reading in 1% increments.
To rapidly increase (or decrease) the humidity reading, press and hold the
CH/+
or
MIN/MAX
button.
To return the indoor humidity to the actual or uncalibrated measurement, press the
SET
button.
Once the displayed indoor humidity equals the calibrated source, wait 15 seconds for timeout, and the
humidity value will stop flashing.
Discussion
: Humidity is a difficult parameter to measure electronically and drifts over time due to
contamination. In addition, location has an adverse affect on humidity readings (installation over dirt
vs. lawn for example).
Official stations recalibrate or replace humidity sensors on a yearly basis. Due to manufacturing
tolerances, the humidity is accurate to ± 5%. To improve this accuracy, the indoor and outdoor
humidity can be calibrated using an accurate source, such as a sling psychrometer or one step
humidpak calibration kits (reference Section 9).
5
Glossary of Terms
Term
Definition
Accuracy
Accuracy is defined as the ability of a measurement to match the actual
value of the quantity being measured.
Hygrometer
A hygrometer is a device that measures relative humidity. Relative
humidity is a term used to describe the amount or percentage of water
vapor that exists in air.
Range
Range is defined as the amount or extent a value can be measured.
