In this state, the system is characterized by the following properties:

• An error has occurred which disrupts normal operation.
• The system issues messages (in the form of Conditions) informing clients about the error; it awaits acknowledgement of these messages, i.e., the information that some client has received the message, and optionally confirmation, i.e., the information that some corrective action has been taken, typically by human intervention.
• The system tries to resolve the error by internal means taking into account the (mandatory) acknowledgement and (optional) confirmation of the messages issued.

This state can be entered from any other state by an automatic transition due to an error detected by the system.

This state can be left by an automatic transition based on the result of the error resolution into any other state, or into Preoperational state by a Reset method call or into Halted state by a Halt method call, provided the requirements on Acknowledgement and Confirmation have been fulfilled. For details on signaling error conditions and on error resolution behavior see Section 11.4.6.

This state can be a composite state with an optional VisionStepModelStateMachineType SubStateMachine.