ATST Software Conceptual Design ATST Conceptual Design Review

ATST Software Conceptual Design ATST Conceptual Design Review 26 Aug 2003

Presentation Structure • Introduction – Approach – Things to watch for • • Requirements Functional design overview Technical design overview Virtual Instrument Model

Design Architectures Requirements Functional Design Technical Design Implementation Behavior

Special points • Configurations – How observations are modeled in system • Virtual Instrument Model – Provides flexibility in laboratory-style operations • Device Model – Uniform implementation and control of devices • Container/Component Model – Flexibility in a distributed environment

Key Science Requirements • Combine multiple post-focus instruments – Operate simultaneously – Coordinated observing with remote sites • Match flexibility and adaptability achieved by DST – Support ‘laboratory-style’ operation (modular instruments) – Support visitor instruments – < 30 min switching time between of active instrument set • >40 year lifetime • Massive data rates • Track on/off solar disk (up to 2 sr off)

Software Requirements Science Requirements Software Requirements Common Sense Software Design Reality

What types are there? • • Functional – what must the system do? Performance – how well must the system run? Interface – how does the system talk with the outside? Operational – how is the system to be used? Documentation – how is the system to be described? Security – who/what can do what/when? Safety – what can’t go wrong?

Functional Design • Purpose – Focus on behavior and structure (what and why) – Measure against requirements • Use cases/Overall design • Information flow • Principal Systems – – Observatory Control System (OCS) Data Handling System (DHS) Telescope Control System (TCS) Instruments Control System (ICS)

Overall Design Approach • Want to adapt a conventional modern observatory software architecture to the special needs of the ATST – Avoid re-invention, but… – Concentrate on multiple instruments operating simultaneously in a laboratory environment – Flexibility is a key requirement of the functional design • Overall functional design derived from ALMA, Gemini, and SOLIS, with consideration from other projects as well. – All share a common overall structure (with wildly different implementations) – All highly distributed with strong communications infrastructure

Overall Design User Interfaces OCS UIs, Coordination, Planning, Services DHS Science data collection Quick look TCS Enclosure/Thermal, Optics Mount, GIS Core Software ICS Virtual Instruments

Information flow Experiment Virtual Instrument Component Observations Configurations Data Device Driver Hardware Component Device Driver Hardware Device Quick Look Engineering Archives

Operating Characteristics • Distributed architecture using a communications bus – – Components can be placed anywhere (and moved as needed) Devices may be constrained by device driver constraints Components locate each other by name, not location Language and other environment choices are independent of behavior – Behavior separated from control by a control surface • Communications bus – – – Multiple channels Provides inter-language peer-to-peer communication Locates components and provides connection handles Monitors connectivity (detects communication failures) High-speed, robust

Observatory Control System (OCS) • Roles: – – – Construct sequence of configurations for each observation Coordinate operation of TCS, ICS, and DHS Provide user interfaces for operations Provide services for applications Provide ATST Common Software for all systems

Data Handling System • Roles – Accumulate science data (including header information) • handle data rates • handle data volumes – Analyze data for system performance (quick look) – Provide archival, retrieval and distribution services

Telescope Control System Requirements • Coordination and control of telescope components – Interface to the Observatory Control System – Configuration management – Safety interlock handling • Ephemeris, pointing, and tracking calculations. – Time base control and distribution – Pointing models – Target trajectory distribution • Image quality – Active and adaptive optics management – Thermal management

Telescope Control System • Subsystems – – – M 1 Control M 2 Control Feed Optics Control Adaptive Optics Control Mount Control Enclosure Control TCS M 1 M 2 Feed Adaptive Mount Enclosure Optics Acquisition, Track, and Guidance • General Systems – Time base – Global Interlock – Thermal Management Image Quality Thermal Management Global Interlock

Telescope Control System • High-Level Data Flows – OCS configurations – ICS configurations – TCS events and archiving OCS cfgs ICS • Low-Level Data Flows – – Subsystem configurations Trajectories Image quality data Interlock events cfgs events TCS Trajectory Interlock cfgs FOCS ECS M 1 CS AOCS M 2 CS Image quality data Global Interlocks

Telescope Control System • Virtual Telescope Model – Tip of the hat to Pat Wallace (DRAL). – Several points of view (Instruments, AO WFS, a. O WFS). • Pointing and Tracking – – – Off-axis telescope should be irrelevant. Tracking will be at solar rate. Coordinate systems include ecliptic and heliocentric. Limited references to build pointing map (1 object/6 months). Open-loop tracking for coronal and non-AO work. Closed loop tracking uses AO as guider. • Thermal Management – Daily thermal profile. – Monitor heat loads and dome flushing.

Mount Control System Pointing and Tracking • • All ephemeris and position calculations are done by the TCS. The MCS follows a 20 Hz trajectory stream provided by the TCS. This stream consists of (time, position) values that the MCS must follow. Current position, demand position, torques, and rates are output at 10 Hz. Thermal Management • • The MCS must keep the mount structure at ambient temperature. May be provided by a separate controller (TBD). Interlocks • • • Interlock conditions cause a power shutdown, brakes on, cover closed. Caused by: GIS, over-speed, over-torque, mechanical obstruction (locking pin, manual drive crank, liftoff failure). Provided by a separate controller (PLC-based) that is always operational.

Mount Control System Servo Requirements Pos = 3 arcsec Vslew = TBD °/sec Vtrk = TBD °/sec Aslew = TBD °/sec 2 Atrk = TBD °/sec 2 Jitter = TBD °/sec Azimuth Bias • • • M 2 Bias 0. 01 Hz Trajectory Elevation Trajectory 20 Hz Trajectory summing and smoothing. Coudé

M 1 Mirror Control System • • Axial Support: blending and averaging AO information, applying force map, correcting servo feedback. Mirror Position: detecting translation and rotation errors, (feedback to actuators? ). Thermal management: controlling temperature, applying thermal profile estimates. Controller: interfacing to TCS & GIS, simulator. TCS GIS AOCS Axial Support Actuators, Force Sensors Force Map M 1 CS Mirror Position Translation, Rotation Sensors Thermal Management M 1 Controller Aperture Stop Interlocks Thermal Profile Interfaces Blowers, Coolers, Exchangers Simulator

M 2 Control System Tip-Tilt-Focus • • Base Configuration TCS Base configuration set by TCS. Corrections from AOCS in 10 Hz stream. Blending data Conversion into off-axis translation and rotation. a. O & AO TTF 10 Hz Tip-Tilt Offset 0. 01 Hz AOCS M 2 CS Thermal Management MCS Blending Thermal Management • • • Secondary Mirror Heat Stop Lyot Stop Conversion Translation X Y Rotation Z X Y Z

Feed Optics Control System Small Mirrors • • M 3: Gregorian feed. M 7: Coudé feed. Other Optics • • • a. O WFS beamsplitter Polarizers Filters? Thermal Management • • • Mirror Cooling Tube Ventilation Coudé entrance

Adaptive Optics Control System a. O WFS Active optics system AOCS AO WFS On Demand TTM 6 DHS OCS 2 KHz On Demand DM 5 M 1 M 2 0. 1 Hz Mount 10 Hz Command Channel Event Channel Data Channel 0. 01 Hz

Adaptive Optics Control System M 2 Tip-tilt bias offload ~0. 01 Hz TTF bias offload ~10 Hz Low-order figure offload ~0. 1 Hz a. O/AOCS Active Optics 10 Hz Adaptive Optics/ Active Optics Control System ~2 KHz WFS Mount M 5 M 1 M 6 Adaptive Optics ~2 KHz WFS Deformable Mirror ~2 KHz Tip-Tilt Mirror ~2 KHz

Enclosure Control System • Azimuth: drives, brakes, encoders, sensors. • Shutter: drive, brakes, encoders, sensors, sun shade • Auxiliary: vent gates, thermal controller, cranes • Controller: interface, interlock, simulator TCS GIS ECS Azimuth Shutter MCS Auxiliary M 1 Controller Drives, Brakes Thermal Management Interlocks Encoders, Sensors Vent Gates Interfaces Sun Shade Cranes Simulator

Instrument Control System Requirements • Laboratory/Experiment Style Observing – Flexible instrument configuration – Use of multiple components • Instruments – Facility instruments follow all ATST interfaces – Visitor instruments obey a minimal set of ATST interfaces – Multiple instruments must work together. • Telescope – Control the beam position – Control modulators, AO, and other image modifiers • Development – Several development locations with numerous partners.

Instrument Control System Management • • Controls the lifecycle of virtual instruments Allocates components Interface • • • Controls configurations from the OCS Provides user interfaces Presents TCS and DHS as resources. Development • OCS Provides standard instrument as template ICS TCS NIr. SP Vi. SP Component Vis. TF Component DHS VI Component VI Component Available Components Component

Instrument Control System Management Lifecycle 1. 2. 3. 4. 5. 6. 7. 8. Select from list of components Build a VI or retrieve an existing VI Register VI with ICS Submit configuration to OCS schedules configuration ICS enables your VI VI takes control of components Interact with your VI [Engineering Mode] OCS 5 4 ICS 3 8 2 My VI 7 1 Available Components 6

Technical Design Overview • Purpose – Focus on implementation issues (how) – Must allow implementation of functional design – Identify options, make choices • Tiered hierarchy – Isolates technology layers – Allows technology replacement

ATST Technical Architecture Applications Admin Apps UIF Libraries Data Handling Support Archiving System Astro Libraries Component Config Error Log Data Time Support DB System Channels System Device Drivers High-level APIs/Tools App Framework Services Container Support Core Support Base Tools APIs & Libraries Development Tools Scripting Support Alarm System Communications Middleware Integrated APIs/Tools

Communications • • Communications Bus Notification Service Synchronous Communications Asynchronous Communications

Services • • • Logging Events Alarms Connection Persistent Stores

Interfaces • Logically separated into three classes: – Lifecycle (startup/reset/shutdown of components) – Functional (command/action/response - behavior) – Service access (connection, log, event, alarm, stores) • Functional interfaces define accessible behavior – Physically extend the lifecycle interface – Narrow interfaces (few commands used) – All devices use a common interface • Formally specified and enforced using communications middleware

Container/Component Model • Industry standard approach to distributed operations (. NET, EJB, CORBA CCM, etc). • Components implement functionality • Containers provide services to components and manage component lifecycle Functional interface Component Container Service interface Lifecycle interface

Containers • ATST supports two types of Containers – Porous – Components provide direct access to their functional interfaces – Tight – Containers wrap component functional interfaces Interface Wrapper

Components • Hierarchically named • Can (currently) be either Java or C/C++ • Three lifecycle models for components – Eternal: created on system start, run to system stop – Long-lived: created on demand, run until told to stop – Transient: exist only long enough to satisfy request • Exist only inside containers – Common base interface allows manipulation by container • Critical attributes maintained in separate persistent store

Observations - 1 • Program of configurations • Configurations flow through system: status is updated as they are operated on by system • Components and devices respond to configurations • Configurations implemented as sets of attributes (name/value pairs) • Configurations are uniquely named and permanently archived (as are observations)

Observations - 2 • • Observations constructed using Observing Tool Choice of OT is TBD (ALMA, Gemini, STSc. I, others) External representation is XML Configurations may be composed from other configurations and components may decompose a configuration into a set of smaller configurations

Observations - 3 • Observation managers track sets of observations as they are operated on by the system • Components tag header information to identify the component associated with the generation of that header information

Real-time Systems • Laboratory-style operations – Rapid setup and reconfiguration – Engineering observations • Inexpensive – Existing software implementation or design – Rapid deployment – Code reuse • Contractual design and development – Easily partitioned work packages – Common infrastructure and tools – Simulators

Device Model • The device model is used by all real-time components – Other models are available for OCS services (log, notification, etc. ). • It provides a common interface to: – – High-level objects (OCS and DHS). Other devices. Low-level hardware drivers. Global services (log, event, database, etc. ). • It can be inherited by more complex devices. • It forces all systems to obey the command/action model. • It operates in a peer-to-peer environment.

Device Model • Devices have common properties: – Attributes: state, health, debug, and initialized. – Command Interface: offline, online, start, stop, pause, resume, get, set. – Services Interfaces: event, database. • Devices have common operations: – Initialize, power-up, check parameters, change state, execute actions, handle errors, respond to queries, receive and generate asynchronous events. • Devices have common communications: – Name/connection registration. – Event listeners and posters. – Databases, log, and alarm services.

Device Command Interface • Devices have a simple command interface: OFF – Offline, online, start, stop, pause, resume, set, and get. • Each command moves the device state machine to another state: offline online offline IDLE – States are: OFF, IDLE, BUSY, PAUSED, FAULT (fault) FAULT stop/done PAUSED start pause (fault) resume BUSY

Configurations • All devices use configurations to transport information. – A group of attributes and corresponding value – i. e. , a filter wheel might act upon: {position=red; rate=10; starttime=10: 38: 18}. – Values may be any native data type, arrays, and lists. • Configurations are followed throughout the system. – Each device action is traceable to a configuration. – Header information is reconstructed from configuration events. • Configurations have states: – A configuration may be in multiple states in multiple devices. – States do not iterate. – Final state has an associated completion code. Created Queued Running Done

Inherited Devices • The Device class is an abstract class; it needs to be inherited by another class. – These classes specify information and operations unique to a particular device. They may create configuration templates, run background tasks, handle hardware control, and generate specific information. – For example, the Motor. Device inherits the Device class to operate servo motors and define positions, limits, power, and brake operations. • An extended class may itself be extended. – The Discrete. Motor. Device inherits the Motor. Device class to provide defined positions and name-to-position conversion.

High-Level Devices • Some devices do not operate hardware, they operate other devices or connect to high-level, non-device objects (OCS/DHS). – The Sequence. Device runs other devices in a defined order and phase. – The Controller. Device executes scripts. – The Multi. Axis. Device coordinates simultaneous actions. • High-level devices are an aggregation pattern. – They do not override or hide the low-level devices. – They allow the low-level devices to operate independently.

Command/Action Model Commands cause external actions to occur. • • A command will return immediately. The action begins in a separate thread. Multiple commands can be given while actions are on-going. This allows us to “stop” an action, or queue up the next “start”. Command Process Config • A device will transition to the BUSY state, then either back to the IDLE state, or to the ERROR state. Synchronization Mechanism Shared Data Actions return asynchronous state information. Actions Response Action Process Completion Actions

Peer-to-Peer Communications • Devices must have flexible connections. – Depending upon the requested operation, a device may need to communicate with several different devices. – Devices must not exclusively control another device. • Peer-to-peer communications allows a loose federation of devices. – No single point failures, outside of the communications system and the naming service. – Multiple federations can exist simultaneously in the system.