Preferences

All settings live in the Settings dialog: File → Settings… or Ctrl+,. Pages are listed on the left; most changes apply when you confirm, and the few that need an application restart (device backends, plugin enable/disable) say so on their page.

🖼️ Image placeholder — Screenshot: Settings dialog with the page list on the left and the Appearance page selected

Appearance

  • Theme — pick from the built-in themes (light and several dark variants); theme plugins can add more. Changes preview immediately.

  • Font size — interface font, 8–24 pt.

User Profile

Set a profile picture and review your identity. The avatar appears in the top-right corner of the main window as a visual indicator of who is signed in.

Network Proxy

Proxy configuration for outbound connections (e.g. reaching facility services through a SOCKS proxy from offsite). Applies to the embedded browser and HTTP clients.

Login & Session

  • Session duration — how long a local-account session lasts before re-authentication: 15 minutes to 8 hours, default 2 hours. Keycloak session lifetimes are controlled by the Keycloak server, not this setting.

External Tools

Selects the code editor Lightfall opens for user plans and plugin files:

  • VSCode — uses the vscode:// URL protocol (registered automatically by VSCode)

  • PyCharm — uses the jetbrains:// protocol, which requires JetBrains Toolbox

The page shows the exact protocol URLs and warns if the handler is not detected.

Devices

Configures the device backends. Multiple backends can be enabled at once; their devices merge into a single catalog. Changes take effect on restart.

Backend

Use

Mock

Simulated devices (ophyd.sim) for development and training — enabled by default. Option to include the noisy detector.

BCS

Real hardware via the Beamline Control System (host, port, timeout, beamline).

Happi

Devices from a happi database (path, beamline filter, instantiation mode).

The page also holds connection settings (device instantiation mode, connection timeout, connect-on-startup) and Remote Access (CA Tunnel) for reaching EPICS Channel Access across networks.

Tiled Data Catalog

Connection to the Tiled data server that backs the Data Browser and Visualization panels and receives acquired runs:

  • Enable toggle and server URL

  • Authentication mode — none, API key, or Keycloak (reuses your Lightfall login)

Logbook

  • Enable logbook backend sync and the server URL, with a connection test

  • Force offline-only mode — local SQLite only, no sync (see Using the Logbook)

IPC

NATS message-broker connection for inter-process features (e.g. Tsuchinoko adaptive experiments, cross-instance notifications): server URL, topic prefix, display name, with a connection status indicator.

Claude Assistant

API endpoint and credentials (API key or Claude Code OAuth), model selection, max turns, and the permission mode. Covered in Claude Assistant.

Assistant Tools

Enable or disable individual agent plugins — the skill prompts and tool bundles available to the assistant.

Plugins

Lists discovered plugins with per-plugin enable/disable and status. Plugin changes take effect on restart. Some plugins contribute their own settings pages, which appear in this dialog alongside the built-in ones.

Visualization

Defaults for the Visualization panel: automatic visualization-type selection (or a fixed default type), performance limits (decimation threshold, update rate), and plot appearance (default colormap, grid).

Where settings are stored

Two mechanisms, both per-user:

  1. Qt state (window geometry, dock layout, sidebar arrangement) — stored via QSettings in the platform-native location (registry on Windows, ~/.config on Linux, plists on macOS).

  2. Typed preferences (everything in the Settings dialog) — the layered config system, with user values in %APPDATA%/ncs/ on Windows or ~/.config/ncs/ on Linux/macOS, over site-wide and packaged defaults.

A handful of preferences (such as device favorites) are additionally synced to your user profile on the settings server when one is deployed, so they follow you between workstations.

Beamline overrides

Deployments can ship site configuration that pre-sets defaults per beamline (device backend, theme, data directories). Your personal settings layer on top of those defaults.

Troubleshooting

A change didn’t take effect

Device backend and plugin changes require a restart; their pages say so. Everything else applies on confirm — if a theme looks wrong after switching, toggle to another theme and back.

Resetting to defaults

Close Lightfall and delete the user config directory (%APPDATA%/ncs/ or ~/.config/ncs/). This clears typed preferences; window layout resets if you also clear the Qt state (on Windows: the ALS/NCS key under HKEY_CURRENT_USER\Software).