Temperature Reaction Time of Simple Hardware Devices¶
Several measuring points are generally used when determining the response time. Each of them is a time period in seconds required for the sensor reading/output to reach x% of the total value change (difference in temperature).
A single time period is known as sensor response time (or thermal response time).
|Percentage||Also used as||Specific term|
|50%||T50 or t0.5||none|
|63.2%||T63 or t0.63||Sensor Time Constant (τau)|
|90%||T90 or t0.9||none|
|99.3%||T99 or t0.99||5 times the Sensor Time Constant (τau)|
EXAMPLE: For a temperature sensor taken out of an ice bath at 0 °C into a room at 10 °C, it will take exactly: -T50 to reach 5°C -T63.2 (Sensor Time Constant) to reach 6.32 °C -T90 to reach 9°C -T99.3 to reach 9.93°C
Please note that T100 (or 100% of the final desired temperature) will never be reached because of the laws of physics.
All the reference data must be also related to the medium used for the test - you need to keep heat transfer and its circulation in mind.
Most commonly found mediums:
- Water with circulation of 0.2 or 0.4 m/s
- Air with circulation of 1 or 2m/s
- And others, any medium needed can be used for the test
Water will have a much faster response times and the faster the circulation, the faster the response time.
Overview of Simple Hardware devices¶
We are using 4 types of devices:
|Device||SimplePack Temp||SimpleMeter||SimpleIndustry (internal probe)||SimpleIndustry (NTC on case)||SimpleIndustry (NTC on cable)|
|Placement||Inside enclosed case||Inside case with air intakes||Inside enclosed case||On the case||On the pipe|
|T63 (sensor only)||15s at 1m/s airflow||15s at 1m/s airflow||15s at 1m/s airflow||4s||15s in water|
|T50 (whole device)||2min (water), 4min (air)||1min (air)||8min (air)||2s||12s in water|
|T63 (whole device)||3min (water), 5min (air)||1.25min (air)||10min (air)||4s||15s in water|
|T90 (whole device)||12min (water), 20min (air)||5min (air)||40min (air)||20s||1min in water|