Logging Calculated Values

[blrooke]

I am logging anemometer data at several levels at a remote site using DF Base. I would like to calculate wind shear and add it to my data file. The formula for wind shear is Ln(WindVel1/WindVel3)/Ln(Height1/Height3). I have read that I will need to use the AddValue command in the event of a channel set to test, A to D, timing 0, channel 0. The two wind velocity channels are U1 and U3 and the heights are in meters. The following is what I've added to the channel event tab:

Wind_Shear.AddValue(Ln(U1[0]/U3[0])/Ln(33.8/20.8))

I have added the new channel to my logging file, added a display value on my home page, and checked the channel graph but nothing shows wind_shear values. What am I doing wrong?

Thanks in advance

Braden

[AzeoTech]

Please post your .ctl document

[AzeoTech]

Alas, you put that script in the event for Wind_Shear. Channel events are run when a new value goes into a channel. Since the only way you have for Wind_Shear to get a new value is with that line of script, and that line of script is in the event for Wind_Shear, it never gets executed.

You want that script in the event for U3.

[blrooke]

Thanks very much. All of my calculated values work now.