Power Supply (Owon) — control, configuration, tests, and quick demo

This guide covers using the Owon bench power supply via SCPI over serial with the framework.

Library: ecu_framework/power/owon_psu.py
Hardware test: tests/hardware/test_owon_psu.py
quick demo script: vendor/Owon/owon_psu_quick_demo.py
Configuration: config/test_config.yaml (power_supply), optionally merged from config/owon_psu.yaml or env OWON_PSU_CONFIG

Install dependencies

pip install -r .\requirements.txt

Configure

You can keep PSU settings centrally or in a machine-specific YAML.

Central: config/test_config.yaml → power_supply section
Separate: config/owon_psu.yaml (or OWON_PSU_CONFIG env var)

Supported keys:

power_supply:
  enabled: true
  port: COM4           # e.g., COM4 (Windows) or /dev/ttyUSB0 (Linux)
  baudrate: 115200
  timeout: 1.0
  eol: "\n"          # or "\r\n" if required
  parity: N            # N|E|O
  stopbits: 1          # 1|2
  xonxoff: false
  rtscts: false
  dsrdtr: false
  idn_substr: OWON
  do_set: false
  set_voltage: 5.0
  set_current: 0.1

The central config loader automatically merges config/owon_psu.yaml (or the path in OWON_PSU_CONFIG) into power_supply.

Run the hardware test

Skips unless power_supply.enabled is true and port is set.

pytest -k test_owon_psu_idn_and_optional_set -m hardware -q

What it does:

Opens serial with your configured line params
Queries *IDN? (checks idn_substr if provided)
If do_set is true, sets voltage/current, enables output briefly, then disables

Use the library programmatically

from ecu_framework.power import OwonPSU, SerialParams

params = SerialParams(baudrate=115200, timeout=1.0)
with OwonPSU("COM4", params, eol="\n") as psu:
    print(psu.idn())
    psu.set_voltage(1, 5.0)
    psu.set_current(1, 0.1)
    psu.set_output(True)
    # ... measure, etc.
    psu.set_output(False)

Notes:

Commands use newline-terminated writes; reads use readline()
SCPI forms: SOUR:VOLT, SOUR:CURR, MEAS:VOLT?, MEAS:CURR?, output 0/1, output?

quick demo script

The quick demo reads OWON_PSU_CONFIG or config/owon_psu.yaml and performs a small sequence.

python .\vendor\Owon\owon_psu_quick_demo.py

It also scans ports with *IDN? using scan_ports().

Troubleshooting

Empty *IDN? or timeouts:
- Verify COM port and exclusivity (no other program holding it)
- Try eol: "\r\n"
- Adjust parity and stopbits per your device manual
Windows COM > 9:
- Most Python code accepts COM10 directly; if needed in other tools, use \\.\\COM10
Flow control:
- Keep xonxoff, rtscts, dsrdtr false unless required

ecu_framework/power/owon_psu.py — PSU controller (pyserial)
tests/hardware/test_owon_psu.py — Hardware test using central config
vendor/Owon/owon_psu_quick_demo.py — Quick demo runner
config/owon_psu.example.yaml — Example machine-specific YAML

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