This property is used to control the generation of the OnTagRead event, which occurs in the I/O Driver that contains the I/O Block Element. If this I/O Block Element's property is set to True, then the OnTagRead event generation is enabled by the I/O Block Element. Otherwise, it does not occur. I/O Tags, I/O Blocks, and I/O Block Elements can generate this event. The event occurs in the I/O Driver, and not in the I/O Block Element.