Logging instrument values
  


After you create an instrument , you can log changes of its value through time with the Log instrument values option from Instruments and markers menu.

After you choose Log instrument values option...  option from the Signal tools menu, you will have to determine the length of the log signal (in samples). A new, empty, signal of the defined length will be created and a new window will appear.

Each time the instrument's value changes, it will be added to the log window - it will work just as old-fashioned paper-tape recorder.

Scrolling and resetting

Log window will monitor all changes in the instrument and add all consecutive values from instrument into one signal. When this signal reaches maximum length you determined, the display will start to scroll, removing oldest values and adding new ones. By choosing Reset data from the Log windows context menu (or pressing F3), you can clear all value and start logging again. By using Start/Stop options from the context menu, you can stop logging and start it again.

X-axis units

Value log signal will try to determine values for its X-axis automatically by backtracking through the analysis chain to the root signal window. If those X values are equidistant (i.e. difference between two consecutive values is always the same), those will be display on X-axis of the instrument log. If not, X-axis will switch to unit called "change" where each new value will simply be labeled with its index, i.e. 0,1,2,3,4,...

Long-time logging of instrument values in a file

Since instrument log keeps its data in your computer's RAM, total storage length is very limited. For long-time recording of signal values, you can use Logging data to file option connected to a log instrument window. For example, this would be a Control Window display of a system to store max. frequency from an FFT into a file.
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Instrument log in this system stores only a last 100 values and can be used for monitoring. File log window, on the other hand, stores all values which are added to a instrument log into a file.


For more information, see Track changes of signal parameters through time How-To section.
Logging instrument values