User Definable Run Control Components

Most of the components in a CODA system are pre-defined by CODA and only require configuring (e.g. setting trigger supervisor options). However, CODA allows for two different user created subsystems and components: the user's trigger subsystem components, and the arbitrary user subsystem components. Each of these components is defined to Run Control as a remote procedure callable (RPC) service. (The CODA/EPICS interface will also be defined in this context.)

Figure 3.1: State Transition Diagram.

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The RPC server defines a pre-defined set of entry points which correspond to the set of state transitions (Figure 3.1) (Create, Config, Download, PreStart, Go, Pause, End, Delete). Values returned by these RPC routines indicate whether the requested action completed successfully, failed, or is still pending (in which case Run Control will periodically request a status update until it succeeds, fails, or a time-out elapses). Details of how to create a user defined component will be given in a future application note.