Safety Gate Introduction

Overview

This document provides an introduction to the Safety gates used at the Vera C. Rubin Observatory, including its components, functional states, and the emergency safety mechanisms in place.

The safety gate is an electronic gateway designed to prevent access to hazardous areas. At the Rubin Observatory, these areas are near the telescope or dome while they are operational. The gate is controlled by the associated Interlock System (IS).

Safety gates at the Rubin Observatory

Simonyi telescope has 2 safety gates, while the AuxTel telescope has one. The table below shows some of their details.

	AuxTel	Simonyi
Gate Location	Bottom of the stairs	- Level 6 - Level 7
Protected area	2nd floor	- Intermediate pier - Level 8
Controlled by IS	AuxTel IS	GIS
Bypass/override button	Outside AuxTel Main Cabinet	GIS Main Cabinet

Components

The main components of the gate are:

1. Frame, the mechanical frame of the gate attached to the floor.

2. Gate can be opened and closed like a regular gate.

3. Handle used to physically open/close the gate, and to attach the gate to the frame.

4. Control buttons to open/close the gate electronically.

5. Status Indicators LEDs that indicate the gate status.

Safety gate components

Gate Functional States

The gate has three functional states: 1: Open, 2: Closed, 3: Error.

Open

When the gate is open, its electronics send an interlock signal to the IS, disabling the drives for the telescope and dome.

Consequently, neither the telescope nor the dome can be operated with the gate open. This ensures that people working in the protected area are safe from unexpected movement.

Closed

When the gate is closed, its electronics clear the interlock to the IS, enabling the drives for the telescope and dome drives.

A closed gate indicates that no one is beyond the gate, making it safe to allow movements.

Warning

It is physically possible to go through the gate without opening it (by entering from the stairs side), but this violates safety protocols and should NOT be done under normal circumstances.

Error

In error mode the gate cannot be locked again. This usually occurs after the emergency release has been activated. This mechanism is described in the next section.

Emergency safety mechanisms

Emergency release

The gate has a safety escape mechanism located behind it, designed to disable the lock in case of emergency.

This mechanism is designed for situations where people might need to be inside while the gate is locked. It is typically used in closed industrial areas, but this is less relevant for our situation. Personnel should not be in proximity to the telescope or dome while they are in operations, except during engineering work.

When the emergency release is pressed the gate enters an Error state and cannot be locked again. This is indicated by a red flashing light on the Status Indicators.

Emergency release mechanism not activated

Gate Emergency Stop

The gate E-STOP behaves the same way as other E-STOP.

Emergency stop button

Gate Bypass/Override

In exceptional cases where engineering work requires people to pass through the gate while the telescope/dome are enabled, a bypass is available.

This override disables the gate interlock, allowing the gate to be opened or closed without triggering the interlock.

AuxTel safety gate bypass

The location of the bypass/override button for AuxTel is on 1st floor, outside the Main cabinet.

Safety gate bypass button in the AuxTel Main cabinet

Note

The override button in AuxTel will soon be replaced by an illuminated action button which will light up when override/bypass is active.

Simonyi safety gate bypass

The bypass/override button for Simonyi is located in the GIS main cabinet on level 2, within Detections and Actions window (Det-Act) under the signals:

• D-5: ‘Unauthorized pier access’

• D-6: ‘Unauthorized pier access’.

Safety gate bypass button in the GIS Main cabinet

Important

If the gate needs to be overridden, you must coordinate with users in the corresponding channel (#summit_auxtel, #summit_simonyi) and ensure that the system is returned to normal once the work is completed.

For instructions on how to operate the gate go to the Safety Gate procedures page.