> ## Documentation Index
> Fetch the complete documentation index at: https://instro.nominal.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Test rack end-to-end demo

```python test_rack.py theme={null}
"""Example: Test rack end-to-end demo.

Demonstrates publishing measurements/commands to a dataset (Nominal Core publisher).

"""

import time

from instro.daq import InstroDAQ
from instro.daq.drivers import Keysight34980A
from instro.daq.types import Direction
from instro.eload import InstroELoad
from instro.eload.drivers import BK85XXB
from instro.eload.types import LoadMode
from instro.lib.transports import SerialConfig, VisaConfig
from instro.psu import InstroPSU
from instro.psu.drivers import BK9115

# Demo assumes a power supply output is connected to the inputs of an electronic load.
# Demo assumes there is a DAQ monitoring this line.

DATASET_RID = "<dataset_rid>"  # Replace with your dataset RID.


def main():
    # ====== SETUP =========
    # Define instruments
    daq = InstroDAQ(
        name="myDAQ",
        driver=Keysight34980A("USB0::0x0957::0x0507::MY44001757::INSTR"),
        dataset_rid=DATASET_RID,
    )
    psu = InstroPSU(
        name="myPSU",
        driver=BK9115("USB0::0xFFFF::0x9115::800422020766920015::INSTR"),
        num_channels=2,
        dataset_rid=DATASET_RID,
    )
    eload = InstroELoad(
        name="myELoad",
        driver=BK85XXB(
            VisaConfig(
                visa_resource="ASRL19::INSTR",
                serial_config=SerialConfig(baud_rate=9600),
            )
        ),
        dataset_rid=DATASET_RID,
    )

    # The context manager opens each instrument on entry and closes them on exit,
    # including if the block raises.
    with daq, psu, eload:
        try:
            # Configure DAQ
            daq.configure_analog_channel(direction=Direction.INPUT, physical_channel="1010", alias="psu_v")
            daq.configure_ai_sample_rate(sample_rate=1000)

            # Start the DAQ to monitor the power supply/eload prior to using it
            daq.start()

            time.sleep(2)  # Let's chill...for fun. Grab a drink

            # Ensure powersupply is in a known state
            psu.output_enable(False, channel=1)
            psu.set_voltage(0, channel=1)
            psu.set_current_limit(1.5, channel=1)

            time.sleep(2)  # More fun. More drinks.

            # Ensure eload is in a known state
            eload.output_enable(False)
            eload.set_mode(LoadMode.CR)  # Constant Resistance
            eload.set_level(10)  # Ohms

            # Start the power supply and eload monitoring
            psu.background_interval = 0.1
            eload.background_interval = 0.1
            psu.start()
            eload.start()

            time.sleep(2)  # More time to drink and chill

            # Power up the power supply
            psu.output_enable(True, channel=1)

            time.sleep(2)  # Drink up, it's time to do work.

            # ========= THE TEST =========
            # Ramp up the PSU voltage
            eload.output_enable(True)
            for voltage in range(10):
                psu.set_voltage(voltage, channel=1)
                time.sleep(1)

            # Now keep the psu the same level and ramp up the eload resistance
            for resistance in range(10, 100, 10):
                eload.set_level(resistance)
                time.sleep(1)
            # ========== END TEST =======

        finally:
            # Put the test stand into a safe state before the instruments close.
            eload.output_enable(False)
            psu.output_enable(False, channel=1)

            time.sleep(3)  # give space so that shutdown is observed


if __name__ == "__main__":
    main()
```