InstroFlowController#

class InstroFlowController(

name: str,

driver: FlowControllerDriverBase,

publishers: list[Publisher] | None = None,

**kwargs,

)[source]#

Bases: Instrument

Flow-controller instrument. Methods return Measurement/Command for publishing.

Initialize an InstroFlowController.

Parameters:

name

Channel-name prefix for published data.

driver

Concrete flow-controller driver; owns its own transport:

fc = InstroFlowController(
    "main",
    driver=AlicatMC("ASRL7::INSTR", "M"),
)

publishers

Publishers that receive emitted Measurement/Command data.
**kwargs

Default tags applied to every emitted Measurement/Command. Pass dataset_rid="<rid>" to auto-create a NominalCorePublisher.

Note

Direct access to driver-specific methods not in FlowControllerDriverBase (e.g., AlicatMC.set_loop_control_variable, gas-mixture methods) bypasses _resource_lock and is the caller’s responsibility to synchronize if mixed with concurrent InstroFlowController method calls.

Attributes

`background_interval`	Seconds between background daemon iterations (0 = no wait).
`channel_names`	Return an insertion-ordered snapshot of all published channel names.

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`	Close the underlying driver and stop the daemon.
`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_flow_data`	Poll the device and publish all live measurements at once.
`get_mass_flow`	Read the current mass flow.
`get_pressure`	Read the current pressure.
`get_process_value`	Read the current process value (primary feedback measurement for control).
`get_setpoint`	Read the current setpoint.
`get_single_channel_value`	Return the most recent sample for `channel_name` from the in-memory buffer.
`get_volumetric_flow`	Read the current volumetric flow.
`open`	Open the underlying driver.
`publish`	Fan `data` out to every configured publisher; `kwargs` pass through.
`select_working_fluid`	Select the active working fluid by name.
`set_setpoint`	Command a new flow setpoint in the device's configured engineering units.
`start`	Start the background daemon thread.
`stop`	Signal the background daemon to stop and join it.
`tare_flow`	Zero the flow reading.

open() → None[source]#: Open the underlying driver.

close() → None[source]#: Close the underlying driver and stop the daemon.

get_flow_data(

**kwargs,

) → Measurement | None[source]#: Poll the device and publish all live measurements at once.

set_setpoint(

value: float,

**kwargs,

) → Command[source]#: Command a new flow setpoint in the device’s configured engineering units.

select_working_fluid(

fluid_name: str,

**kwargs,

) → Command[source]#: Select the active working fluid by name.

tare_flow(**kwargs) → Command[source]#: Zero the flow reading. Device must have zero flow when called.

get_setpoint(

**kwargs,

) → Measurement | None[source]#: Read the current setpoint. A subset of get_flow_data(); driver implementations may fetch a full frame internally.

get_mass_flow(

**kwargs,

) → Measurement | None[source]#: Read the current mass flow. A subset of get_flow_data(); driver implementations may fetch a full frame internally.

get_volumetric_flow(

**kwargs,

) → Measurement | None[source]#: Read the current volumetric flow. A subset of get_flow_data(); driver implementations may fetch a full frame internally.

get_pressure(

**kwargs,

) → Measurement | None[source]#: Read the current pressure. A subset of get_flow_data(); driver implementations may fetch a full frame internally.

get_process_value(

**kwargs,

) → Measurement | None[source]#

Read the current process value (primary feedback measurement for control).

The key used in the channel name is determined by the driver’s process_value_source property. For mass-flow controllers this is mass_flow; for liquid-flow controllers, volumetric_flow; etc.

add_background_daemon_function(

method: Callable,

*args,

**kwargs,

)#: Append method to the daemon’s call list. Use define_background_daemon to replace instead.

add_publisher( publisher: Publisher, )#: Register a publisher to receive this instrument’s Measurement/Command data.

property background_interval#: Seconds between background daemon iterations (0 = no wait).

property channel_names: tuple[str, ...]#

Return an insertion-ordered snapshot of all published channel names.

Names are complete after one full daemon iteration: {name}.loop_time publishes every iteration, so call get_channel(“loop_time”, wait_for_new_samples=True) then read channel_names to ensure the complete set has arrived.

Raises:: RuntimeError – No background buffer; start() was not called.

define_background_daemon(

method: Callable,

*args,

**kwargs,

)#: Replace all daemon functions with a single method (called with the given args).

get_channel( channel_name: str, length: int = 1, wait_for_new_samples: bool = False, timeout: float = 10.0, ) → Measurement#

Return the most recent length samples for channel_name from the in-memory buffer.

If the channel does not exist yet, or no sample is available, the code will always block until timeout expires.

Parameters:

channel_name

Name of the channel to retrieve.
length

Number of trailing samples to return.
wait_for_new_samples

Block until at least length new values arrive.
timeout

Seconds to wait when insufficient data exists or wait_for_new_samples=True.

Raises:

RuntimeError – No background buffer; start() was not called.
ChannelNotFoundError – channel had no values and no data appeared before timeout. wait_for_new_samples=True and channel did not appear within timeout.
ChannelValueTimeoutError – wait_for_new_samples=True and values did not arrive within timeout.

get_single_channel_value( channel_name: str, ) → float | str | None#

Return the most recent sample for channel_name from the in-memory buffer.

This will not wait, if data is not available then None is returned.

Parameters:

channel_name

Name of the channel to retrieve.

Raises:

RuntimeError – No background buffer; start() was not called.

publish(

data: Measurement | Command,

**kwargs,

)#: Fan data out to every configured publisher; kwargs pass through.

start()#: Start the background daemon thread. No-op if already running.

stop()#: Signal the background daemon to stop and join it. No-op if not running.