# Cycle Duration Measurement

To measure the duration of a cycle, select Cycle Duration in the drop-down box:

<figure><img src="https://1039220062-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FRhWtYvkHNZy7Jvdnc3wk%2Fuploads%2FQdCKCY0TIK7zCUgoKB2m%2Fimage.png?alt=media&#x26;token=4fbaf690-37d4-4fa4-9ae8-2fff4b852cc6" alt=""><figcaption></figcaption></figure>

Frequency can then be calculated using the following formula:

#### F = 1 / T

In this case, this frequency is NOT average frequency. It is instantaneous frequency.

The KBox will wait until the cycle measurement is finished before sending a CAN message with the duration. If the cycle duration is long, the messages may be sent slower than the selected Rate.   &#x20;

If the Cycle duration is shorter than the time between messages set by the Rate, the duration will be re-calculated before being sent.