Measuring Total Time Above A Voltage

[embayweather]

I am using a Labjack U3 to run a weather station, connected to professional level instruments. I need to be able to measure sunshine hours, and this occurs when a voltage output from the sensor is greater than 2.5 Volts. When there is no or low sunshine amounts the voltage level is 0 volts. What is the best expression to use to total time above a certain voltage, clearly for the total reading each day. At the end of the day I would manually reset along with the other instruments .

Thank you for your advice.

Best wishes

Mike

[AzeoTech]

Create a Test Channel with Timing 0, call it "totalSunshine". In your input channel's event (I'll say its called "sunshine") put script like this:

if (sunshine[0] > 2.5)
   totalSunshine.addValue(insertTime(totalSunshine[0] + (sunshine.time[0] - sunshine.time[1]), systime(), 0))
else

   totalSunshine.addValue(insertTime(totalSunshine[0] , systime(), 0))
endif


[/CODE]
The else part is optional.  It will simply ensure your totalSunshine channel has the same number of points as your sunshine channel. Note that you'll have to initialize / reset totalSunshine to 0 somewhere by doing:
totalSunshine.addValue(0)
The code simply adds the difference in time between two consecutive sunshine readings when the latest reading is > 2.5.  The insertTime() function ensures the new data point has the current time and not the time of the last reading.