On 06/22/2012 03:34 PM, Guenter Roeck wrote: >> + * Response time for the sensor is measured in seconds, so we have > > in seconds ? So, how to word it then... In the datasheets words, "The measurement cycle duration is typically 36.65 ms for temperature and humidity readings." However we also have Table 2. Humidity Performance Specifications Characteristic Condition Min Typ Max Unit Response time airflow minimum 20 l/min – 6 8 s Table 3. Temperature Performance Specifications Characteristic Condition Min Typ Max Unit Response time 1/e slow moving air 5 - 30 s So although we can run a measurement in around 40ms it will take the sensor longer to react to a change. I agree this needs to be clear, or there's no point to the comment. Just that you're asking suggests it's not clear enough. Suggestions ? How about this: While the measurement can be completed in ~40ms the sensor takes much longer to react to a change in external conditions. How quickly it reacts depends on airflow and other factors outwith our control. The datasheet specifies maximum 'Response time' for humidity at 8s and temperature at 30s under specified conditions. We therefore choose to only read the sensor at most once per second. This trades off pointless activity polling the sensor much faster than it can react against better response times in conditions more favourable than specified in the datasheet. Too much ? Iain _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
