Filter
Top Products
136 LogTag Analyzer
Sensor Responsiveness
Temperature sensors typically respond to changes in the environment temperature in a
logarithmic way and as such you will find that the responsiveness of temperature sensors
(how quickly a sensor responds to an environmental temperature change) is expressed in
terms of T90. T90 represents the time it takes for a logger to respond to 90% of the
actual change of the environmental temperature.
For example, if the actual environment temperature suddenly changed from 15° to 45°
and the T90 of the sensor was 30 minutes, then 30 minutes after this sudden change the
sensor would be reading (15 + (45 - 15) * 0.90) 42°. In reality, it is rare for the
temperature of an environment to suddenly change to a very different temperature and
then suddenly change again, usually it is a gradual incremental process.
For example, if the actual environment temperature changed from 15° to 45° over a
period of 5 hours in a linear fashion, that is after 2 hours the temperature was 27° and
after 4 hours the temperature was 39°, and the T90 of the sensor was 30 minutes, then
when after 5 hours of this temperature change, that is the actual environment
temperature was 45°, the sensor would be reading 44.7°.
The LogTag is designed to produce a rapid response to temperature changes, which is
possible because the actual sensor element of the logger system is external to the logger
body itself. You can actually touch the tip of the bare thermistor element with your finger.
The T90 of the LogTag is less than 5 minutes in moving air, which is very responsive as
some temperature recorders can take up to an hour for the T90 of the temperature
change to be recorded.