Typical drive functions

The functions available on a modern digital drive are so numerous that only the most studious of users will be aware of the capabilities of the drive. Although many of the functions will be common across all manufacturers, some will be unique and others subtly different. Intelligent drives offer the user the opportunity to write their own specific functions that will then run on the drive. Input and output terminals on many drives will also be configurable, that is to say that the function controlled by or driving the terminals can be set by the user. It is important to note, however, that a well-designed drive will leave the factory with a default configuration that will cater for a large proportion of basic applications without the need for the user to make many or any changes to operate. Software tools are also available to guide the user through the configuration of their drive. The objective of this section is to describe in general terms the sort of functions the user may expect to find on a typical industrial drive, and what they do. In demanding applications care needs to be taken about issues such as the sample/update times of given inputs and outputs (also relevant for data communicated through serial buses). The user should consider the cost benefit of utilising such functions that exist within the drive. Less obvious is the potential improvement in performance obtained by using a function within the drive because communication time to the control loops is likely to be quicker than using an external controller. Sample and update rates must be taken into account for demanding applications. For convenience the functions have been grouped in order to illustrate the types of functions that are available and to allow the reader to readily find specific functions. The list is not exhaustive.