Document Number: ESO-288424

Introduction

This document is intended to be used as a general/common reference for the terminology used in the ELT ICS Framework documents.

This documented will be updated with more concepts and acronyms as the work on the ELT ICS documents progresses.

Scope

This document is applicable to the IHL and the documents produced in this context.

Abbreviations and Acronyms

AD	Applicable Document
ADC	Atmospheric Dispersion Corrector
AIWS	Auxiliary Instrument Workstation
AO	Adaptive Optics
API	Application Programming Interface
BOSS	Base Observation Software Stub (VLT)
CA	Control and Acquisition
CCD	Charge Coupled Device
CCS	Central Control System (ELT)
CDB	Configuration Database
CFITSIO	C FITS I/O toolkit (https://heasarc.gsfc.nasa.gov/fitsio/fitsio.html)
CII	Core Integration Infrastructure
CLIP	Common Library for Image Processing (VLT)
COTS	Commercial Off-The-Shelf (components)
CPL	Common Pipeline Library
DB	Database
DCS	Detector Control System
DD	Data Display
DDT	Data Display Tool
DFS	Data Flow System
DPM	Data Product Manager
DROT	De-Rotator
ELT	Extremely Large Telescope
EMF	Eclipse Modeling Framework
Enc	Encoder
EVH	Event Handling toolkit (VLT)
FB	Function Block (PLC programming)
FCS	Function Control System
FITS	Flexible Image Transport System
FSM	Finite State Machine
FW	Framework
FWHM	Full Width Half-Maximum
GM	Guiding Manager
GUI	Graphical User Interface
HDU	Header Data Unit (FITS)
HQ	Head Quarters
I/O	Input/Output
ICD	Interface Control Document
ICS	Instrument Control System
ID	Identification
IEEE	Institute of Electrical and Electronic Engineers
IHL	Instrument High-Level (framework)
ILS	Interlock System
IR	Infrared
ISO	International Standardization Organization
IWS	Instrument Workstation
MGR/mgr	Manager
MTT	Model Transformation Tool
MVC	Model View Controller
OCF	Observation Coordination Framework
OCM	Observation Coordination Manager
OCS	Observation Coordination System
OS	Observation Software (VLT)
PLC	Programmable Logic Controller
PWM	Pulse Width Modulation
RF	Reference Document
RTC	Real-Time Computer
RTD	Real-time Display (VLT)
SCAO	Single Conjugate Adaptive Optics
SCXML	StateCharts eXtensible Markup Language
SDK	Software Development Kit
SSM	Subsystem Manager
SM	State Machine
SysML	Systems Modeling Language
TBC	To Be Confirmed
TBD	To Be Defined
TBI	To Be Investigated
TCCD	Technical CCD
TCS	Telescope Control System (VLT)
TRS	Time Reference System
UM	User’s Manual
UML	Unified Modeling Language
UTC	Universal Time Coordinated
UU	User Units
VCS	Version Control System
VLT	Very Large Telescope
VLTSW	VLT Software
WAN	Wide Area Network
WCS	World Coordinate System
WFS	Wave-front Sensor
WS	WorkStation
XMI	XML Metadata Interchange

Terminology

Adapter:

See Software Adapter.

Assembly:

An assembly is a static and configurable definition of device parameter settings.

Automation:

The control of a process by automatic means.

Auxiliary Instrument Workstation (AIWS):

Workstations used in connection with the Instrument Workstation to carry out specific tasks. May be used to offload the Instrument Workstation.

Block:

A Block is the basic unit of structure in SysML and can be used to represent HW, SW, facilities, personnel, or any other system element.

Block Definition Diagram:

A Block Definition Diagram describes the system hierarchy and system/component classifications.

Component:

A Component is a SW entity representing a logical or physical function or service of the ICS. Could e.g. be a Device Control Component.

Control GUI:

GUI used for control purposes.

Control Unit:

A Control Unit is a general purpose computing unit aimed for controlling and monitoring remotely or locally standalone HW Functions. A control unit may coordinate a set of HW Adapters interconnected through a local or distributed bus system. A control unit can be programmed using standard programming languages and is designed to be used in industrial environments. A typical control unit for instruments is a PLC.

Data Acquisition:

The process of acquiring data captured by the science detectors, TCCD’s or other systems, acquiring/producing science data or supporting metadata.

Data Display (DD):

See DDT.

Data Display Tool (DDT):

The application used by the ICS to display data on-the-fly or offline.

Data Interface Dictionary (DID):

Text document that defines the properties of parameters used for a given subsystem. In particular, the properties of FITS keyword cards are defined in DIDs. At this point in time, the format is based on YAML, but it may be that the CII Configuration Service will be used for this purpose.

Data Product:

A FITS data file that is created by the Data Product Manager from data acquired in an Observation. This will be archived and later delivered to the Instrument user.

Data Product Manager (DPM):

OCF application handling the final assembly and creation of the Data Products before submitting these for archiving.

Device:

A Device encapsulates the high and low level control SW to control an Hardware Function. It includes the supervisory part as well as the Local Device Controller running on a control unit such a PLC.

Device Controller:

A Device Controller is the SW implementing the control of a HW Function, e.g. a Function Block for the control of shutters. Several instances of Device Controllers may run inside a control unit. Its interface is generic so that multiple, similar HW functions can use the same interface. The Device Controller functionality is restricted to the direct access to the HW.

Device (Hardware) Simulator:

This is the SW part of the Local Device that emulates the hardware interfaces and behaviour of the Hardware Function, allowing the testing of the Device Controller functionality.

Device:

Application to monitor and control the lower level control logic and HW of a Function.

Manager:

This is the high level control SW of a Device.

Exposure:

Refers to one data acquisition executed with a detector, e.g. infrared or CCD, resulting in one science data file.

Exposure Meter:

Application used to estimate the number of photon counts, to provide an input for adjusting the necessary detector exposure time.

FITS Keyword Card:

One 80-character entry in a FITS file, e.g. containing the key, the value and a comment.

Function:

See Hardware Function.

Guiding Manager (GM):

OCF application used to implement guiding facilities in OCS.

Hardware Adapter:

A Hardware Adapter is acting as an interface between general purpose control units and HW functions with specific requirements or purpose, e.g. for real-time control applications. It provides normally two interfaces, one toward the control unit via a bus system (local or fieldbus), and the other one toward the Hardware Function (electronic). Some typical Hardware Adapters are, but not limited to:

• Motion controllers.

• Piezo controllers.

• PWM drives.

• I/O modules.

• Temperature and vacuum controllers.

• RS-232 coupler or module.

Hardware Function:

Any actuator or sensor that is part of the instrument and controlled by the ICS. Examples of a HW is a shutter, a filter wheel or a cabinet control unit.

Hierarchical FITS:

Extension to the standard FITS keyword format, allowing a hierarchical keyword structure of the form “HIERARCH <ID> <category> [<sub system>] <parameter>”.

Image Data File:

The science output.

Initialization Sequence:

Sequence of commands or operations executed to initialize e.g. a HW Function. Could be a motorized function.

Input Channel:

Refers to the representation of an input signal in the ICS, e.g. temperature or pressure sensor.

Instrument:

The astronomical instrument that is operated by a control system.

Instrument Configuration:

A particular composition for an instrument – made up of individual instrument components and represented in SW by a component description.

Instrument Mode:

Refers to a specific setup of the instrument, to use it for a certain purpose.

Instrument Workstation (IWS):

The main computer on which the central coordination of the instrument SW is executed.

Integration Time:

Time a detector is exposed and the pixels integrating on a given object.

Internal Block Diagram:

The internal block diagram describes the internal structure of a system in terms of its parts, ports, and connectors.

Layer:

A major logical division usually used to organize the control SW; for example, the “Supervision Layer”.

Local Control System (LCS):

A Local Control System is the part of the ICS dealing with the HW control. It is composed of at least one local control unit, e.g. a PLC, and a number of Device Controllers.

Local Device (LD):

It refers to the group of software components running within the LCS and dealing with the control of one hardware function. It includes the Device Controller, the Device Hardware Simulator and the Device HMI.

Model Transformation Tool (MTT)

Responsible for the transformation mapping the abstract notation into platform specific code.

Named Position:

A position defined and named in the configuration of a motorized function.

Observation:

Refers to the sequence of activities to

• setup the telescope and instrument, and to

• perform data acquisitions which results in one or more sets of science and metadata data files.

Observation Block (OB):

Refers to a high level view of telescope operations. An observation block is the smallest schedulable observational unit for a telescope. It contains all information necessary to execute sequentially and without interruption a set of correlated data acquisitions, involving a single target (i.e. a single telescope preset). It contains amongst other things the description of which Templates to execute with which parameters.

Observation Coordination Framework (OCF):

ICS Framework component used to create an OCS.

Observation Coordination Manager (OCM):

OCF application that carries out the overall coordination of all ICS sub-systems and interfaces with the telescope control and detectors. It also coordinates the creation of Data Products.

Observation Coordination System (OCS):

The system responsible for observation coordination. It consists of the Observation Coordination Manager, Data Product Manager, one or more Subsystem Managers, zero or more Guiding Managers and the scripts implementing the scientific observation sequences.

Operational Log Entry (OpsLog):

An Operational Log Entry is an event logged by the ICS SW in order to record instrument operations and their results at a given time. A typical case for an operational log would be the operation of a change of filter position or a new acquired value from a temperature sensor.

Output Channel:

Refers to the representation of an output signal in the ICS, i.e., a signal that is set by the ICS.

Sensor Virtual Channel:

Sensor Virtual Channels are inputs that can be read from other SW components and not necessarily related to physical values coming from a HW device. A Virtual Channel may be the result of a computation, using other signals read as inputs.

Sequencer:

The Sequencer is the SW application, which handles the execution of a series of operations defined in one Observation Block.

Setup:

A Setup defines a set of parameters that is applied to the instrument in order to prepare it for a certain operation. A Setup may be submitted as a set of single parameters in commands, or as a collection of parameters contained in a document (file).

Software Adapter:

A SW Component that is used to separate the business logic of the core SW from context specific implementation. It might e.g. be a Component implementing the communication between an application and the entity it is communicating with.

Software Component:

See Component.

Software Platform:

A collection of SW tools, providing a specific SW programming ‘eco-system’. The Qt SDK is an example of a Software Platform.

Status GUI:

A GUI used to display the status of the complete Instrument under control, or just parts of it. No control actions are possible from a Status GUI.

Template (TPL):

An executable script, which executes a specific type of observation.

Tier:

A major physical division. It refers to the environment where code is deployed and executed. For example, a “control and automation tier” might refer to a group of controllers providing the interface with the HW.

Widget:

A Widget is a reusable GUI Component, which can be deployed in panels e.g. to represent a physical or logical function of a system.