This section provides an overview of the state machines and device status variables used in the LADS Companion Specification. It explains the relationship between various state machines and status variables in the context of a LADS Device, its Components, and Functional Units.

The relationship between these state machines and status variables is crucial for understanding the operation and management of a LADS Device. The state of the LADS Device state machine and the FunctionalUnit state machines come first and form the basis for the MachineryItemState. The MachineryOperationMode provides additional context about the type of Tasks being performed. The DeviceHealth and DeviceHealthAlarms provide information about the device's condition and any Alarms that may have been triggered.

Refer to Annex B for proposed mappings between the DeviceStateMachine, the FunctionalUnit state machines, the MachineryItemState and the DeviceHealth.

The DeviceStateMachine provides a domain-specific view of the device's state. It reflects the condition of the Device itself.

The MachineryItemState provides a harmonized state machine across various domains, particularly in mechanical engineering. It serves as a semantic stack light, providing a high-level system with a quick overview of the device's operational status.

The MachineryOperationMode indicates the type of Tasks being performed by the Device. It may not be known by the MachineryItem itself and might need to be provided by an external source, like an MES system or the operator.

Each FunctionalUnit within a LADS Device has an independent FunctionalUnit state machine. For instance, a device with three FunctionalUnits will have three separate FunctionalUnit state machines. These state machines are process oriented and can operate independently. They may also include sub-state machines for the running state. These state machines come first, and their states form the basis for the MachineryItemState.

ControlFunctions also have a FunctionStateMachine, similar to the FunctionalUnitStateMachine. This state machine provides a detailed view of the operational state of the ControlFunctions.

The DeviceHealth and DeviceHealthAlarms provide information about the device's condition and any Alarms that may have been triggered. They are optional and can be implemented at both the Device and Component levels. The DeviceHealth status variable provides a quick overview of the device's health status, while the DeviceHealthAlarms variable provides detailed information about any specific Alarms that may have been triggered.