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472 Data Collection
4. Select one of the following options:
• Click Start to start the playback and save the settings.
• Click OK to save the settings for use on the next playback.
Repeating the Playback
1. Select Experiment > Replay > Start Playback.
2. Click Start to start the playback and save the settings.
Adjusting Derivative Settings
Use this option to select the number of points to use in derivative calculations.
This value affects the tangent tool, velocity, and acceleration values.
Find pH derivative settings using a calculated column.
The Vernier DataQuest™ application can determine a numeric derivative from a
list of data with respect to another list of data. The data can be collected using
sensors, input manually, or linked with other applications. The numerical
derivative is found using a calculated column.
To determine the numerical 1st derivative of List B with respect to List A, enter
the following expression in the Column Options dialog:
derivative(B,A,1,0) or derivative(B,A,1,1)
To determine the numerical 2nd derivative of List B with respect to List A, enter
the following express:
derivative(B,A,2,0) or derivative (B,A,2,1)
The last parameter is either 0 or 1 depending on the method you are using.
When it is 0, a weighted average is used. When it is 1, a time shifted derivative
method is used.
Note: The first derivative calculation (weighted average) is what the Tangent
tool uses to display the slope at a data point when examining data. (Analyze >
Tangent).
Note: The derivative calculation is completely row based. It is recommended
that your List A data be sorted in ascending order.
1. Click Options > Derivative Settings.
The Settings dialog box opens.