ModbusDevice

class ModbusDevice(

config: ModbusConfig | dict | Path | str,

connection: ModbusTransport | dict | None = None,

name: str | None = None,

publishers: list[Publisher] | None = None,

autostart: bool = False,

unit_id: int | None = None,

**kwargs,

)

Bases: Instrument

Config-driven Modbus client. Semantic access by register alias from a ModbusConfig.

Initialize a ModbusDevice.

Parameters:

• config – A ModbusConfig, a dict (validated via Pydantic), or a path to a JSON config.

• connection – Overrides config.connection. Accepts a ModbusTransport (pass the same instance to several devices to share one line; unit_id is then required), or a dict (with transport = "tcp" / "rtu"), which builds a private transport. Required if the config has no connection section.

• name – Channel-name prefix; falls back to config.device.name.

• publishers – Publishers that receive emitted Measurement/Command data.

• autostart – When True, open the connection and start background polling. Requires a timing section (with poll_interval) — passing autostart=True without one is an error.

• unit_id – Modbus unit/slave address (0-255; 0-247 on serial). May also come from the connection block’s unit_id field; values given in both places must agree. Required alongside a shared transport; defaults to 1 when this device builds its own private transport.

• **kwargs – Default tags applied to every emitted Measurement/Command.

Raises:

ValueError – No connection in args or config, an address that is missing, conflicting, or out of range, or autostart=True with no timing section.

Attributes

background_interval	Seconds between background daemon iterations (0 = no wait).
channel_names	Return an insertion-ordered snapshot of all published channel names.
unit_id	set once at construction, via the constructor kwarg or the config.

Methods

add_background_daemon_function	Append method to the daemon's call list.
add_publisher	Register a publisher to receive this instrument's Measurement/Command data.
close	Release this device's hold on the transport and stop the daemon; the line closes when the last device leaves.
define_background_daemon	Replace all daemon functions with a single method (called with the given args).
get_channel	Return the most recent length samples for channel_name from the in-memory buffer.
get_single_channel_value	Return the most recent sample for channel_name from the in-memory buffer.
open	Open the Modbus TCP/RTU connection, registering this device as an owner of the transport.
publish	Fan data out to every configured publisher; kwargs pass through.
read	Read the register named alias and return the scaled value.
start	Start the background daemon thread.
stop	Signal the background daemon to stop and join it.
write	Write value to the register named alias.