A binding is a correspondence between two entities that allows information be passed between them (either in one of the directions, or in both directions).

The main parts of binding are:

• (Binding) Source: The external data you want to bind to. Here you select e.g. the OPC item, update rate etc. You can also select which “part” of the data you want to bind to (e.g. just the value, or just the quality information, etc.).
• (Binding) Target: Defines element in your application that will be bound to the binding source. This is typically a value target (see Value Targets).
• Binding Operations: Which operations the binding is involved in.
• Binding Groups: Which binding group the binding belongs to.
• Value Conversion: Allows you to convert the values on their way to/from the binding target.
• Event Links: Defines events in your application that will automatically cause binding operation be performed.

The types of bindings that are available depend on the binder in use (see further below). For the (most common) PointBinder, there is just one type of binding available, a PointBinding. The point binding can be e.g. for an OPC-DA item, an OPC-DA property, or for OPC-UA data (node attribute).

There may be multiple bindings associated with a control. With this feature, you can, for example, bind a value (converted to string) to the actual text box’s text, while binding the status information to its color.