Introduction¶

Reference Documents¶

[RD1]: Central Control System Development Standards;

ESO-366378 v1
[RD2]: ELT - Technical note on Standard Application Interface and State Machine;

ESO-321402

Standard Interface¶

Standard interface, stdif, is the interface to be used by all components that implement the standard ELT interface and state machine [RD2].

This documentation provides an overview of the interface. For data structures only the data members are documented, not the accessors generated by MAL. Similarly names are not fully qualified as it is different across the supported languages.

Interfaces¶

class stdif.StdCmds¶

Standard interface.

Stop() → String¶

Stop any ongoing activity.

Returns: A string with information about the execution of the request.
Return type: String
Raises: stdif::ExceptionErr – On error.

Init() → String¶

Command to request the initialization of the Application. After successful initialization, the Applicaiton will be NotOperational::Ready The Application cannot drive any movement, monitoring is available and it is ready to be Enabled.

Returns: A string with information about the execution of the request.
Return type: String
Raises: stdif::ExceptionErr – On error.

Reset() → String¶

Command to perform a full reset of the Application and re-enter the NotOperational::NotReady state

Returns: A string with information about the execution of the request.
Return type: String
Raises: stdif::ExceptionErr – On error.

Enable() → String¶

Command to request to enable the Application, i.e. to allow executing movements. After successful Enable, the Application will be Operational.

Returns: A string with information about the execution of the request.
Return type: String
Raises: stdif::ExceptionErr – On error.

Disable() → String¶

Command to move back from Operational to NotOperational, stopping and disabling any movement.

Returns: A string with information about the execution of the request.
Return type: String
Raises: stdif::ExceptionErr – On error.

GetState() → String¶

Command to request the state of the Application, i.e. the complete (for example composite if the state machine has multiple regions) state of the internal state machine

return

A string with information about the execution of the request.

rtype

String

raises stdif::ExceptionErr

On error.

GetStatus() → String¶

Command to request the “System Status” (to be better defined and dependent on the specific application). For Supervisor applications, the output format shall be:

<aggregated state>;<aggregated substate>

Applications shall report the same through the Status topic.

Returns: Format: “<state>;<substate>”.
Return type: String
Raises: stdif::ExceptionErr – On error.

GetVersion() → String¶

Returns the Application’s version string.

Returns: A string with information about the execution of the request.
Return type: String
Raises: stdif::ExceptionErr – On error.

Exit() → String¶

Requests the Application to Exit. The Application shall stop any ongoing activity, go to safe conditions, cleanly shutdown and exit any process. At the end of the Exit, the State as published in the OLDB shall be OFF.

Returns: A string with information about the execution of the request.
Return type: String
Raises: stdif::ExceptionErr – On error.

SetLogLevel(info) → String¶

Sets the logging level for the Application.

Parameters: info – structure including the level and the logger information.
Returns: A string with information about the execution of the request.
Return type: LogInfo
Raises: stdif::ExceptionErr – On error.

Data Structures¶

class stdif.ExceptionErr¶

Exception class thrown in case an error is encountered while handling a request.

code: int¶: Exception (error) code allocated to the specific exception; 0 if no code is allocated.

desc: str¶: Description of the exception (diagnostics).

class stdif.State¶

Provides the current state of the application state machine engine.

source: string¶: Indicates the name of the application instance updating the topic.

state: string¶: String having the format returned by the application state machine engine.

class stdif.Status¶

Defines the topic that shall be used by subsystems to inform supervisors about theirs status. For Supervisor applications, the output format shall be:

<aggregated state>;<aggregated substate>

source: string¶: Indicates the name of the application instance updating the topic.

status: string¶: String having the format <state>;<substate>

class stdif.LogInfo¶

Defines the structure to be passed to the SetLogLevel method.

level: string¶: String specifying the log level.

logger: string¶: String specifying the name of the logger.