How to Calculate the Derivative/ Rate of Change of a Channel
VBOX Test Suite Software contains a Maths Channel facility which can be used to calculate the Derivative/ Rate Of Change (the rate at which the selected channel is changing at every sample) of a VBOX channel.
It is calculated using the following formula:
Value in present sample - Value in previous sample) / Time difference between both samples
To setup a channel with a Rate of Change function, please follow the instructions below:
- Open the desired saved file within VBOX Test Suite Software, or if you are intending to view live VBOX data ensure that the software is in Online Mode.
- Select the 'Maths Channel' button from the Test Setup Ribbon Bar to open the Maths Channel creator.
- Click on the 'Add' button on the top left of the window to add a new Maths Channel. Select the channel added on the left and then click within the equation editor to the right to start creating the channel.
- Select the Channels dropdown menu. The standard channels are the GPS channels which are captured by default and can always be accessed, the additional channels are any configured CAN channels or any existing Maths Channels.
- To apply the Rate of Change function, hover over the arrow > next to the desired channel and select 'Rate of Change' from the popup.
- The channel will now be added to the equation editor area with Rate of Change applied.
Longitudinal Acceleration Rate of Change example
- Enter a name for the Maths channel and Click ‘OK’ to save changes.
- This new channel is now available for use wherever a channel can be added within the software, for example as a Gauge on the Dashboard, as a Channel within a Test Configuration, as a Column within Test Results or as an Axis on the Chart.
- If the VBOX data file is saved from the software, the configured maths channel is included within the file.