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instro ships with a built-in SCPI simulator, so you can try the full library without owning any hardware. This page walks through installing instro, launching the simulator, driving it from Python, and reading a measurement back.
1

Install instro

The base install is enough for everything in this quickstart. Optional extras like [daq] pull in vendor-specific dependencies. Install those later when you need them (see Installation).
pip install instro
2

Start the simulated PSU

Open a separate terminal and start the bundled simulator. It listens on 127.0.0.1:5025 and stays running until you press Ctrl+C.
python -m instro.psu.scpi_sim_server
Leave it running in the background while you work through the rest of the steps.
3

Construct an InstroPSU

In a new Python session or script, create an InstroPSU backed by the SimulatedPSU driver. The driver owns the VISA transport. You pass it the simulator’s socket resource string, and InstroPSU handles everything else.
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()
InstroPSU is the category-level interface. SimulatedPSU is one of several drivers. Swap in BK9115, RigolDP800, SiglentSPD3303, or TDKLambdaGenesys to talk to real hardware without changing the rest of your code.
4

Set a voltage and enable the output

Configure channel 1 with a 5 V setpoint and a 1 A current limit, then enable the output.
psu.set_voltage(5.0, channel=1)
psu.set_current_limit(1.0, channel=1)
psu.output_enable(True, channel=1)
5

Read a measurement back

Measurement getters return a Measurement object. Use .latest to grab the current value. Every measurement is timestamped and tagged automatically, ready to stream to a Publisher.
voltage = psu.get_voltage(channel=1)
current = psu.get_current(channel=1)
print(f"V: {voltage.latest:.3f} V")
print(f"I: {current.latest:.3f} A")
When you’re done, disable the output and close the connection:
psu.output_enable(False, channel=1)
psu.close()
That’s the whole loop: construct → open() → configure → measure → close(). Every instrument category in instro follows the same shape.

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Two ways to manage the lifecycle

You can drive the instrument with explicit open() / close() calls, or let Python do it for you with a with block. Both are first-class. Pick whichever fits your script. Every instro instrument is a context manager. __enter__ calls self.open(), __exit__ calls self.close() (including when an exception escapes the block, so the daemon and publishers always get torn down). This works for every built-in category (InstroPSU, InstroDMM, InstroDAQ, InstroELoad, I2CInterface, …) and for any custom Instrument subclass (see Custom instruments).
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()

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Where to next

Library overview

How instruments, drivers, publishers, and the background daemon fit together.

Power supplies in depth

Multi-channel use, supported vendors, custom driver development, and the background telemetry daemon.

Stream to Nominal Core

Attach a publisher in one line to ship measurements live to Nominal Core, Connect, or a file.

Examples gallery

Runnable end-to-end scripts for every supported instrument category.