Connections

Connections (spx_core/system/connections.py) copy values between attributes each time the simulation runs. They are handy for routing sensor data into controllers without writing custom actions.

Configuration Example

YAML

connections:
  - sensor_to_controller:
      from: sensor.attributes.temperature
      to: controller.attributes.input_temperature
  - flow_feedback:
      from: "#attr(pump.flow)"
      to: "#external(tank.inflow)"

JSON

How it works

• Each entry becomes a Connection component with a run() method that reads the source wrapper and writes the destination wrapper.

• Sources and destinations can use plain dotted paths (sensor.attributes.temperature) or explicit wrapper syntax (#attr(...), #external(...)).

• Connections run as part of the standard model loop, so values stay in sync automatically.

Validation & logging

• The container accepts lists or dicts; mixed formats are normalized internally.

• If the source or destination cannot be resolved, the connection raises a ValueError during load so you catch mistakes early.

• At runtime, errors are logged with the connection name; this helps QA trace broken signal paths.

Tips

• Use connections for simple mirroring. If you need math (scaling, offsets), combine them with actions (e.g., a function action that multiplies before writing to the target).

• Group related connections in the YAML and comment them; you will thank yourself during troubleshooting.

• Remember that connections overwrite the destination every cycle—do not point them at values users need to edit manually unless you intend to clamp those values.