Components and functionality

The TwinCAT HMI Process library consists of HMI controls and functions, for example, formatting functions, which help to present values in a more convenient format.

Most HMI controls have a hierarchical inheritance structure (only Service and Lock View controls are separate):

The ProcessObject element inheritance The ProcessObject element is a parent of most of other controls. That means that these controls inherit ProcessObject properties, functions, and events, but some of them may be unavailable in inheriting controls.

The information below is organized so that parent element properties, functions, and events are described first in the ProcessObject chapter. Furthermore, these members of the ProcessObject can be applied to the inheriting controls and are not considered separately for each inheriting control (Controls chapter). If a member of the parent is changed for the inheriting control, then relevant information is provided. For each control having its special properties, functions and events are given relevant descriptions of the ones.

Using ProcessObject and Base Elements as controls The ProcessObject can be instantiated as a control but does not have any graphical representation by default. It will receive its faceplate based on the Data Symbol property. The Base Elements cannot be used as controls.