Introduction

ELT-VLT gateway or evltgw allows the communication between a VLT instrument software using the ELT software technological stack and a VLT telescope. It consists of two components:

  • eltGW: interface exposed to the instrument

  • vltGW: interface to the VLT environment.

The main functionalities of the evltgw are:

  • Forward commands from INSSW to the telescope

  • Forward updates of the VLT OLDB telescope data point to its ELT OLDB counterpart

  • Forward commands from VLT INSSW to an ELT component (e.g. COSMIC)

  • Forward updates of configurable ELT OLDB telescope data points to their VLT OLDB counterparts

  • Instrument alarms forwarding

  • Instrument log and telemetry ingestion in datalab

  • Retrieval of telescope fits header and binary tables

  • Providing the TCS state either with PUB/SUB or REQ/REP

evltgw version 1.0.1 is the first version to be deployed on dedicated servers in Paranal. These servers will still be out of the telescope network until the first instruments based on the ELT development environment are commissioned in Paranal.

Scope

This document is the transfer document for the ELT-VLT gateway (evltgw). The intended audience are developers of INSSW or software quality assurance engineers.

Acronyms

AOF

Adaptive Optics Facility

CAS

Central Alarm System

CII

Core Integration Infrastructure

CCS

Central Control System (VLT)

DAO

Data Access Object

DHS

Data Handling System

ECCS

ELT Telescope Central Control System

ELT

Extremely Large Telescope

evltgw

ELT VLT Gateway

INSSW

Instrument control software

IPC

Inter-process communication

IWS

Instrument Workstation

LGSF

Laser Guide Stars Facility

MAL

Middleware Abstraction Layer

OCM

Observation Coordination Manager

OLDB

Online Database

OT

Observation Tool

TCS

Telescope Control System (VLT)

VM

Virtual Machine

vOT

Visitor Observation Tool

ZMQ

ZeroMQ

Overview

The ELT-VLT gateway software is stored in the evltgw waf project that consists of the following packages:

../_images/packages.png
It consists of two applications, ELTGW running on an ELT DevEnv IWS and VLTGW running on a VLTSW2024 virtual machine or on TCS WS.
All the CII services for the configuration, online database and telemetry will run either on a specific host or on the ELT IWS. These services can be shared by all instruments relying on CII or they can be specific to an instrument.
../_images/deployment.png