V

velocity

A vector quantity that denotes magnitude (for example, speed) and direction in relation to a given frame of reference.

velocity command

The desired velocity used by the control loops to move the feedback element to match.

velocity loop

A feedback control loop in which the controlled parameter is motor velocity. It usually uses a tachometer for a feedback device.

velocity profile

The shape of the velocity command over time such as trapezoid, triangular, or sinusoidal.

velocity timebase

The time (in seconds) to be used for calculating the average velocity of an axis. The average velocity is computed by taking the total distance the axis travels in the time specified, and dividing this value by the timebase.

The velocity timebase value should be large enough to filter out the small changes in velocity that would result in a "noisy" velocity value, however, small enough to track significant changes in axis velocity. A value of 0.25 to 0.50 seconds should work well for most applications.

verification

The process of checking the project file for syntax or semantic errors made while programming. Missing, incorrect, or inconsistent entries will be flagged and displayed to the user during this operation.

verified

The state in which an item has a complete and valid configuration as determined by the system.

To better accommodate different users’ workflow, RSLogix systems allow items to exist within a project even though they have an incomplete or invalid configuration (for example, an instruction may reference a tag that does not yet exist). An item that has a complete and valid configuration exists in a verified state while an item that has incomplete or invalid configuration exists in an unverified state. A project that contains items in an unverified state cannot be downloaded to a controller. The process of checking unverified items is called verification.