VP-3
User’s Manual
6. Installation
22
6. Installation
Installation in a Radiation Shield
Relative humidity is measured at the temperature of the humidity
sensor. For this to be an accurate representation of the
atmospheric humidity, it is critical that the humidity sensor be at
air temperature. For most outdoor and greenhouse measurement
scenarios, the VP-3 should be housed in a radiation shield with
adequate air flow to allow the sensor to come into equilibrium
with air temperature. In general, the higher the wind speed, the
more accurate the temperature and relative humidity
measurements will be. A radiation shield is not critical for non-
greenhouse, indoor monitoring applications where radiation
loading is small.
Decagon’s radiation shield comes with a mounting bracket and
seven discs that prevent direct sunlight from coming into coming
contact with the sensor. This isolation from solar radiation
prevents false readings of elevated temperatures, allowing for
accurate measurement of ambient air temperature. To install the
sensor in the radiation shield follow the directions below:
1. Gently pry the white cap from the bottom center hole of the
radiation shield.
2. Slide the white cap onto the cable of the sensor.
