pySimBlocks.blocks.interfaces.bus_from

class pySimBlocks.blocks.interfaces.bus_from.BusFrom(name: str, tag: str, sample_time: float | None = None)

Bases: Block

Read a signal from the global signal bus by tag.

BusFrom and Goto blocks implement a virtual wiring mechanism: a Goto writes its input to signal_bus._signal_bus[tag] each tick, and this block reads that value without requiring an explicit connection in the model graph.

The model’s topological sort injects a virtual edge from each Goto to every BusFrom sharing the same tag, ensuring the Goto executes before this block within the same tick.

direct_feedthrough = True

True if outputs depend directly on inputs.

initialize(t0: float) → None

Read the initial value from the signal bus if available.

If the tag is not yet in the bus (Goto not yet initialized), the output is set to None.

Parameters:

t0 – Initial simulation time in seconds.

output_update(t: float, dt: float) → None

Read the current value from the signal bus.

Parameters:

• t – Current simulation time in seconds.

• dt – Current time step in seconds.

Raises:

KeyError – If no Goto with the matching tag has written to the bus in this run.

state_update(t: float, dt: float) → None

No-op: BusFrom carries no internal state.