Common Services Components

1
Common ServicesComponents

• Bret Goodrich
• 21 March 2005

2
Components
Controller void start(IConfiguration) v
oid stop(String) void
pause(String) void resume(String) void
done(IConfiguration) Void
aborted(IConfiguration) void
_start(IConfiguration) void
_stop(String) void _pause(String) void
_resume(String) void
_done(IConfiguration) void
_aborted(IConfiguration) void
_action(IConfiguration)
Component IattributeTable get(IAttributeTable) voi
d set(IAttributeTable) void
_init(IAttributeTable) void
_startup(IAttributeTable) void
_shutdown() void _remove()
Device void offline(void) void
online(IConfiguration) void
_offline(void) void _online(IConfigurat
ion)
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Components

• Components are the basic building blocks of ATST
  applications
• Technical interface
• Connections to ATST Containers
• Lifecycle support
• Communications support
• Services support
• Functional interface
• Extensible
• Cannot be natively implemented
• Contain no functional data
• Subclasses add specific application functionality

4
Technical Interface

• Creation
• Container constructs a component and associated
  toolbox
• The component should add no construction
  functionality

• Initialization
• Get list of default attributes
• Get metadata for attributes
• Do local initialization
• buffers, drivers, etc.
• Startup
• register name
• Do local startup
• subsystems, events, logs, etc.

Container
new
Component
new
Toolbox
init
Property.getMetaData
_init
Connection.register
startup
_startup
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Technical Interface

• Operation
• handle services calls through toolbox
• periodically check on health

• Shutdown
• release external resources
• subsystems, events, etc.
• unregister name
• Remove
• stop all activities
• release internal resources

Container
Component
Toolbox
healthCheck
_health
Log.debug
shutdown
_shutdown
Connection.unregister
remove
_remove
delete
delete
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Technical Interface

• Abstract methods written by a subclass
• _healthCheck test the health of the component
• GOOD, WARNING, BAD, (not UNKNOWN).
• should actively test threads, drivers, and
  resources.
• _init perform internal initializations
• typical one-time calls (memory allocation, driver
  initialization)
• cannot use Common Services
• _startup
• external calls (event subscription, logging)
• connection to other Components via Common
  Services
• _shutdown
• disconnect from Common Services
• _remove
• delete or destroy all internal resources

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Functional Interface

• The functional interface for Components supports
  attribute values
• Is externally visible through the communications
  IDL
• Can only get and set values
• Changing the attribute list is done through the
  OCS database tools
• Extending the Component class adds new
  functionality
• IAttributeTable get (IAttributeTable)
• fills an attribute table with corresponding
  values
• void set (IAttributeTable)
• sets values from the input attribute table

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Controllers

• A Controller implements the ATST application
  framework
• ATST components expect specific behavior from
  other components
• Command-Action-Response model
• Configurations
• Configuration lifecycle
• Controllers enforce this behavior by
  implementation
• subclass of Component
• thin functional command interface
• action thread pool
• Controllers are usually at the top of a systems
  hierarchy
• provide control mechanisms for subsystems

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Controllers

• Public Commands
• start queue an input configuration
• stop stop the named configuration
• pause pause the named configuration
• resume resume the named configuration
• done/aborted callback from an action
• Protected Commands
• _start/_stop/_pause_resume user-supplied
  routines
• _action user-supplied action routine
• Attributes
• starttime/stoptime optional queue start and
  stop
• threadmodel/numthreads/activethreads
  thread-specific operations

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Command-Action-Response

• Command
• control configurations, not actions
• do not block
• queue configurations
• Action
• perform work in the background
• multiple, simultaneous actions
• Response
• 1st after command accepted
• 2nd after action completes
• associated configuration ID

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Configuration Control

• Configurations are created by the OCS and
• sent throughout the ATST systems
• must follow a sequence of states
  QUEUED?RUNNING?DONE
• Controllers enforce the sequence and
• enforce it in their subsystems
• keep the state of their slowest subsystem

Subsystems
Queued
Running
Done
Queued
Running
Done
Queued
Running
Done
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Hierarchies

• Controllers manage a list of other controllers
• startup/shutdown makes and breaks connections
• start passes configurations down
• stop/pause/resume pass down configuration control
• done tallies all subsystem states
• User routines modify the behavior of the
  hierarchy
• _start breaks down configuration into subsystem
  configurations
• mcs.pos becomes mcs.az.pos and mcs.alt.pos
• mcs.az.rate passes through the upper system

TCS
MCS
M1CS
M2CS
ECS
FOCS
AGCS
WCCS
Azimuth
Cover
Altitude
GIS
Aux
Brakes
Servo
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Action Thread

• Execute specialize actions
• Start any subsystems
• Wait for all subsystems to return
• Generate DONE response

Subsystem
start
Command
Action
Action
sync
_action
(return)
start
Command
start
_action
(return)
Event.post(configstate)
Callback
done
_done
Event.post(configstate)
delete
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Devices

• Devices add real-time control to the ATST
  application framework
• protect critical resources
• allow only one operational thread
• provide unique device states
• add interface to initialize hardware
• Devices are a subclass of Controller
• expands the interface
• increases the number of operational states
• constrains the number of configurations to one

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Commands

• Additional Device commands apply to the hardware
• online hardware initialization (power on,
  brakes, homing)
• offline hardware shutdown (power off, brakes)
• Application-specific commands
• _online/_offline
• _start
• _stop/_pause/_resume
• _get/_set

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Device States

• Device states allow the controller to have finer
  control over the hardware
• OFF The device is in the lowest state, the
  default.
• IDLE The device is able to accept positioning
  commands
• BUSY The device cannot be interrupted
• PAUSED The device is suspended
• FAULT The device has detected a fatal error

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MotorDevice

• The MotorDevice adds typical motor operations.
• home a routine to position and index the motor
• toRaw conversion to encoder units
• fromRaw conversion to user units
• And attributes
• pos/cpos demand and current position
• rate/crate maximum and current rate
• acc/cacc maximum and current acceleration
• dec/cdec maximum and current deceleration
• limits current set limits switches
• channel driver board channel
• The MotorDevice is extended into several
  subclasses
• DiscreteMotorDevice adds incremental positions
• Rate MotorDevice adds continuous rate motion

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SequenceDevice

• The SequenceDevice allows hardware operations in
  a given order
• a subsystem can be placed in any numbered phase
• all subsystems in a phase complete a busy-done
  cycle
• the next phase is then begun
• Sequences are useful for staging
• A sequencer is used to read a camera
• phase 1 move mechanisms
• phase 2 configure camera
• phase 3 wait for trigger
• phase 4 transfer data