Temperature and Humidity Sensor
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700-THS3 Rev. 6 -05 May 2015
Chapter 1
Introduction
1.1
General Description
The THS-3 is a combined analog Temperature and Relative Humidity sensor. Temperature is sensed
by an encapsulated thermistor housed in a stainless steel tube. Thermistor contacts are brought
directly to the sensor connector for easy temperature measurement. Relative Humidity is measured
using a capacitive-type humidity transducer. A microprocessor internal to the THS-3 sensor measures
the transducer humidity, performs the appropriate conversion, and outputs a voltage proportional to
the relative humidity (0 to 1 Vdc equals 0 to 100% RH) on the sensor connector.
The T/H sensor assembly (see Figure 1-1) houses the sensors and associated electronics. Both sensors
are protected from air-borne contaminants by a replaceable sensor filter. The sensor assembly is
mounted to an anodized aluminum base and housed inside white louvers that make up the solar
screen. The purpose of the screen is to prevent solar heating of the sensors that would introduce
large inaccuracies in the data. At the same time, airflow is permitted to aid in correct ambient
readings.
The sensor is mounted on an aluminum sensor support arm that can be attached to a mast or tower.
Figure 1-1: THS-3 Temperature and Humidity Sensor – Exploded View
Solar Screen
T/H Sensor Filter
T/H Sensor
T/H Sensor Cable Interface
Support Arm
U Bracket and Bolts
