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Quick start — your first run on the simulator

This walkthrough takes you from a fresh capa install to a sealed run bundle in about five minutes. No real hardware needed — every device referenced here has a built-in simulator.

1. Launch capa

uv run capa gui

You should see the welcome screen with three cards: New setup, Open config, Try a simulator.

2. Open the simulator config

Click Try a simulator. capa loads configs/experiments/sim_freerun.yaml, a stock free-run config with one simulated Watlow heater and one simulated Alicat mass-flow controller.

The Setup tab opens. The connection strip at the top shows Connected — draft matches rig. The status bar pills at the bottom start showing live values for sat, loop, and q — the simulator is already streaming samples.

3. (Optional) Edit a setpoint

Click the Experiment entry in the outline. Find Heater setpoint [°C] — change it from 25 to 50. The connection strip now reads Connected — draft has 1 unsaved edit and the Apply & Connect button lights up.

Click Apply & Connect. The strip cycles to Connecting… for a moment, then back to Connected — draft matches rig.

4. Start the run

Switch to the Run tab. The state badge says ● Idle · Free run. The plot pane shows axes and channel legends but no data yet.

Click Start. The state badge flips to Running, the elapsed timer ticks up, and the plot starts drawing live samples from the simulators.

5. Stop the run

Click Stop run. capa runs the safe-shutdown step and seals the bundle. The badge shows Sealed and the status bar's bundle: label displays the new bundle path.

6. Find the bundle

Open Help → Open logs folder. The bundle lives under runs/<timestamp>/manifest.json has the metadata, events.sqlite has the event log, and scalars.parquet has the channel data.

Next steps

  • Open the Method tab and click + Add a hold step to script a multi-step run.
  • Read the glossary for short definitions of bundle, method, channel binding, and other capa-specific terms.
  • The status bar guide explains every pill in the diagnostic strip — sat, loop, q, etc.