InstroELoad#

Bases: Instrument

Electronic-load instrument. Methods return Measurement/Command for publishing.

Initialize an InstroELoad.

Provide either config or driver, not both.

Parameters:

name

Channel-name prefix for published data. Falls back to config.device.name when config is given.

driver

Concrete E-Load driver; owns its own transport:

eload = InstroELoad(
    "main",
    driver=BK85XXB("ASRL19::INSTR"),
)

publishers

Publishers that receive emitted Measurement/Command data. Combined with any publishers declared in config.
config

An ELoadConfig, a dict, or a path to a JSON config file. Its load block is applied through the public setters on open(); the input is never enabled from config.
autostart

When True, open the connection and start background polling.
**kwargs

Default tags applied to every emitted Measurement/Command. Pass dataset_rid="<rid>" to auto-create a NominalCorePublisher (uses the on-disk ‘default’ Nominal credential).

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_current`	Measure the current (amperes) sensed on `channel`.
`get_single_channel_value`	Return the most recent sample for `channel_name` from the in-memory buffer.
`get_voltage`	Measure the voltage (volts) sensed on `channel`.
`open`	Open the underlying driver and apply any configured load state.
`output_enable`	Enable or disable the output on `channel`.
`publish`	Fan `data` out to every configured publisher; `kwargs` pass through.
`set_level`	Set the operating level in the active mode's units (CC: A, CV: V, CP: W, CR: Ω).
`set_mode`	Set the channel's operation mode: CC, CR, CP, or CV.
`set_range`	Set the range from the expected maximum operating value in the active mode's units (CC: A, CV: V, CP: W, CR: Ω).
`set_slewrate`	Set the per-edge current slew rate (A/μs) for `direction` (RISE/FALL/BOTH).
`short_output`	Enable or disable the channel short.
`start`	Start the background daemon thread.
`stop`	Signal the background daemon to stop and join it.

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

open() → None[source]#: Open the underlying driver and apply any configured load state.

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

set_mode(

mode: LoadMode,

channel: int = 1,

**kwargs,

) → Command[source]#: Set the channel’s operation mode: CC, CR, CP, or CV. Not all models support every mode.

set_level(

value: float,

channel: int = 1,

curr_limit: float | None = None,

**kwargs,

) → Command[source]#

Set the operating level in the active mode’s units (CC: A, CV: V, CP: W, CR: Ω).

curr_limit applies only in CV mode. Raises ValueError if no mode has been set.

short_output(

enable: bool,

channel: int = 1,

**kwargs,

) → Command[source]#: Enable or disable the channel short.

Warning

Takes effect IMMEDIATELY. enable=True shorts the channel output.

set_range(

value: float,

channel: int = 1,

**kwargs,

) → Command[source]#

Set the range from the expected maximum operating value in the active mode’s units (CC: A, CV: V, CP: W, CR: Ω).

Raises ValueError if no mode has been set.

set_slewrate(

direction: SlewRateDirection,

rate: float,

channel: int = 1,

**kwargs,

) → Command[source]#: Set the per-edge current slew rate (A/μs) for direction (RISE/FALL/BOTH).

output_enable(

enable: bool,

channel: int = 1,

**kwargs,

) → Command[source]#: Enable or disable the output on channel.

get_current(

channel: int = 1,

**kwargs,

) → Measurement | None[source]#: Measure the current (amperes) sensed on channel. Returns None if unavailable.

get_voltage(

channel: int = 1,

**kwargs,

) → Measurement | None[source]#: Measure the voltage (volts) sensed on channel. Returns None if unavailable.

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 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.