Using instro

Using instro with some more detail

This page discusses details about using instro.

Instruments

Two ways to get data

You can acquire measurements from an instrument in two ways. The difference is who triggers the reads and how often.

	Background acquisition	On-demand acquisition
How	Call start(). A background daemon reads from the instrument at a fixed, configurable rate. Pull the latest N values with get_channel() when you need them.	Call read methods (read_analog(), get_voltage(), …) only when you want a measurement.
Best for	Apps where data should always be available and publishing.	Apps that need measurements only at specific times; lower system and bus load. DMMs are a good example.

open()/close() or with block

Instruments can also be open/closed automatically using a with block.

Explicit open() / close()

Best when the instrument’s lifetime spans many functions, or when you want to interleave setup and teardown across event handlers, fixtures, or REPL sessions.

from instro.psu import InstroPSU
from instro.psu.drivers import SimulatedPSU

psu = InstroPSU(
    name="bench_psu",
    driver=SimulatedPSU("TCPIP0::127.0.0.1::5025::SOCKET"),
    num_channels=2,
)
psu.open()

psu.set_voltage(5.0, channel=1)
psu.set_current_limit(1.0, channel=1)
psu.output_enable(True, channel=1)

voltage = psu.get_voltage(channel=1)
print(f"V: {voltage.latest:.3f} V")

psu.output_enable(False, channel=1)
psu.close()

with block

Best for scripts and tests where the instrument is used inside a single scope. close() runs automatically on the way out, even if an exception is raised.

from instro.psu import InstroPSU
from instro.psu.drivers import SimulatedPSU

with InstroPSU(
    name="bench_psu",
    driver=SimulatedPSU("TCPIP0::127.0.0.1::5025::SOCKET"),
    num_channels=2,
) as psu:
    psu.set_voltage(5.0, channel=1)
    psu.set_current_limit(1.0, channel=1)
    psu.output_enable(True, channel=1)

    voltage = psu.get_voltage(channel=1)
    print(f"V: {voltage.latest:.3f} V")