Controller Data Flow Capabilities

Standard tags and logic behave the same way that they do in a standard controller.

Standard tag data, program- or controller-scoped, can be exchanged with external HMI devices, personal computers, and other controllers.

Controllers with safety functions are integrated controllers with the ability to move (map) standard tag data into safety tags for use within the safety task. This is the only way to get standard tag data into the safety task. Safety logic in the safety task cannot read or write the standard tag that is the source in the tag mapping data transfer; it can only reference the safety tag destination of the mapping. But, it can read and write that safety tag.

ATTENTION

: Mapped tag data does not have SIL rated safety integrity. Safety functions requiring a rating of SIL 2 or SIL 3 must use appropriately rated safety inputs.

Controller-scoped safety tags can be read directly by standard logic.

Safety tags can be read or written by safety logic.

Safety tags can be exchanged between safety controllers over Ethernet or ControlNet networks.

Safety tag data, program- or controller-scoped, can be read by external devices, such as HMI devices, personal computers, or other standard controllers. External devices cannot write to safety tags (whether the controller is protected or not).

Once this data is read, it is considered standard data, not SIL 3/PLe data.