A vision system will frequently make use of a number of resources, like camera drivers, files, databases etc. which will need to be properly closed before shutting down that system.

In Halted state, the system shall have put all resources into a state where it is safe to power down the system. However, not all operation is stopped, because the system can be brought out of Halted state by a call to the Reset method, transitioning to the Preoperational state.

The vision system may decide to enter Halted state due to internal conditions or by calling the Halt method on the OPC UA server.

The Halt method shall always be executable. If for some reason the system is not capable of carrying out the transition, the VisionStateMachine shall transition into the Error state.