ANSI C Based OPC UA Client/Server SDK
1.8.4.410
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Programs are complex functions in a server or an underlying system that can be invoked and managed by a client. Programs can represent any level of functionality within a system or process in which client control or intervention is required and progress monitoring is desired.
Programs are state full and transition through a prescribed sequence of states as they execute. Their behaviour is defined by a Program Finite State Machine (PFSM). The elements of the PFSM describe the phases of a Program’s execution in terms of valid transitions between a set of states, the stimuli or causes of those transitions, and the resultant effects of the transitions.
The ProgramStateMachineType describes four states and nine transitions:
State | Description |
---|---|
Ready | The Program is properly initialized and may be started. |
Running | The Program is executing making progress towards completion. |
Suspended | The Program has been stopped prior to reaching a terminal state but may be resumed. |
Halted | The Program is in a terminal or failed state, and it cannot be started or resumed without being reset. |
No. | Transition name | Cause | From state | To state | Effect |
---|---|---|---|---|---|
1 | HaltedToReady | Reset Method | Halted | Ready | Report Transition 1 Event/Result |
2 | ReadyToRunning | Start Method | Ready | Running | Report Transition 2 Event/Result |
3 | RunningToHalted | Halt Method or Internal (Error) | Running | Halted | Report Transition 3 Event/Result |
4 | RunningToReady | Internal | Running | Ready | Report Transition 4 Event/Result |
5 | RunningToSuspended | Suspend Method | Running | Suspended | Report Transition 5 Event/Result |
6 | SuspendedToRunning | Resume Method | Suspended | Running | Report Transition 6 Event/Result |
7 | SuspendedToHalted | Halt Method | Suspended | Halted | Report Transition 7 Event/Result |
8 | SuspendedToReady | Internal | Suspended | Ready | Report Transition 8 Event/Result |
9 | ReadyToHalted | Halt Method | Ready | Halted | Report Transition 9 Event/Result |