P. DuhouxEuropean Southern Observatory

July 2002 TSW Tutorial

LSF - the LCU Server Frameworkeasy creation of LCU applications

with Object Oriented approach

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ATCS - the Initiator

• Large number of new sub-systems

• Control of standard devices (motors, signals, serial links, monitoring and background tasks)

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LSF is a Framework

• Fixed design and architecture

• Improved code reuse thus reduced maintenance costs

• Enforce VLT standards

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LSF is for SW Devices

• SW device must support Standard Commands at ACI and API level

• Behavior of standard commands is defined once

• Any number of specific commands may be added

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LSF handles State & SubState• State machine is 100% LCC

• State transitions are fully defined while additional behavior may be implemented

• The concept of sub-state has been introduced that gives more precise information on the SW device status

• Automatic and systematic restoration of DB configuration at Initialization

• Monitoring activity allowed in

any initialized state

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LSF supports various devices

• LSF supports many types of standard devices

• All device types derive from the base device

• New device types can be easily added

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LSF imposes the SW architecture• Minimum behavior for all

standard commands is provided

• Additional behavior by means of user defined hooks

• Table driven control

• Monitoring of device state and sub-state

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LSF imposes the DB structure•All classes are derived from the base class lsfDB_DEVICE

•A SW device is a kind of SoftDev

•Specificity is achieved by sub-classing

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LSF database branch

Device types

Device instances

Run-time data

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LSF supports Overloading• Fixed thread of control for

all standard commands with several hooks for additional behavior

• sub-SW devices are always handled first

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LSF schedules the Activities• The state and sub-state of a

device are updated during the activities.

• All devices of a type are processed simultaneously

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LSF Base Device

• Minimum classes for all the devices

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LSF Devices

• All device types are built on the same scheme

• The device types are providing all minimum behavior as of the associated HW device

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lsftpl - the Application Template 1• Template application used

both for tests and for the creation of new applications

• Fully scalable to the needs of the new application

• Provides implementation examples for most of the device types

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• The creation of a new module is based on 3 utilities:– lsfCreate: create an instance based

on the template– lsfConfig: customize the module to

the needs– lsfBackup: generate a DB backup

file

• It requires the edition of a couple of files prior to invoking lsfConfig

lsftpl - the Application Template 2<<cmm module>>

lsftpl<<raw module>>

app

<<customized module>>app

Edit some files

lsfCreate app

<<cmm module>>app

LCU

Build applicationBuild WS & LCU

environments

Load on LCUTune devices

cmmArchive app

lsfConfig app

lsfBackup

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Maintenance & Tests

• Core is implemented once in lsf– standard behavior can easily be modified/improved– all lsf-based applications updated at once

• Minimum tat test provided with the template– only specific tests shall be implemented

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LSF is a Standard• LSF has (shall) become the de-facto standard for all new LCU

applications (INS excluded).

• All new VLTI sub-systems are based on lsf:– ATCS

– OPD, Transfer Optics (M16 and Temperature Sensors)

– VCM

– FINITO

– Coudé

– MACAO VLTI (RTC and ICS parts)

• Future applications– PRIMA FSU and Metrology

– SINFONI, CRIRES ???

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Conclusions

• LSF has now been instantiated about 30 times in various configurations in the last 18 months.

• Most of the maturity problems have been solved and it shows a good level of reliability

• LSF re-inforces our standards

• LSF allows the designer to concentrate on the application specific issues