Configuring Stations #

This guide covers station configuration for different environments.

Basic Station Config #

# stations/bench_1.yaml
id: bench_1
name: "Production Bench 1"
location: "Lab A"
 
instruments:
  dmm:
    type: dmm
    driver: pymeasure.instruments.keysight.Keysight34461A
    resource: "TCPIP::192.168.1.100::INSTR"
  psu:
    type: psu
    driver: pymeasure.instruments.keysight.KeysightE36312A
    resource: "GPIB0::5::INSTR"

Station Fields #

Field	Required	Description
`id`	Defaults to filename stem	Unique identifier — must match the filename stem if declared explicitly
`name`	Yes	Display name
`location`	No	Physical location
`description`	No	Description
`supported_phases`	No	Documents which phases this bench is set up for — shown in the stations UI

Instrument Fields #

Per StationInstrumentConfig:

Field	Required	Description
`type`	Yes	Instrument type (dmm, psu, etc.)
`driver`	At least one of driver/resource (unless `mock: true`)	The driver to load, written `package.module.DriverName` (e.g. `pymeasure.instruments.keysight.Keysight34461A`)
`resource`	At least one of driver/resource (unless `mock: true`)	VISA address or connection string
`catalog_ref`	No	ID of a catalog entry that declares this instrument's capabilities
`channels`	No	Named channel aliases (`dict[str, str]`)
`description`	No	Human-readable description
`mock`	No	Always mock this instrument (even without `--mock-instruments`). Default `false`
`mock_config`	No	Return values when running in mock mode

Using a station's instruments in a test #

Each role under instruments: becomes a pytest fixture of the same name. A dmm: role gives you a dmm fixture; psu: gives psu. Rename the role, rename the fixture.

def test_rail_voltage(dmm, psu):
    psu.voltage = 5.0
    reading = dmm.measure_dc_voltage()
    assert 3.2 < reading < 3.4

The fixtures are session-scoped — Litmus connects each instrument once and shares the driver instance across all tests in the run.

VISA Addresses #

TCP/IP (LAN) #

resource: "TCPIP::192.168.1.100::INSTR"
resource: "TCPIP::192.168.1.100::5025::SOCKET"  # With port
resource: "TCPIP::dmm.lab.local::INSTR"  # DNS name

GPIB #

resource: "GPIB0::5::INSTR"   # Board 0, address 5
resource: "GPIB1::12::INSTR"  # Board 1, address 12

USB #

resource: "USB0::0x2A8D::0x0101::MY12345::INSTR"
# Format: USB{board}::{vendor}::{part}::{serial}::INSTR

Serial #

resource: "ASRL/dev/ttyUSB0::INSTR"  # Linux
resource: "ASRLCOM3::INSTR"          # Windows

Mock Mode Configuration #

Configure default values for --mock-instruments mode:

instruments:
  dmm:
    type: dmm
    driver: pymeasure.instruments.keysight.Keysight34461A
    resource: "TCPIP::192.168.1.100::INSTR"
    mock_config:
      measure_dc_voltage: 3.31
      measure_current: 0.1
      measure_resistance: 1000

Running in Mock Mode #

pytest tests/ --station=stations/bench_1.yaml --mock-instruments --uut-serial=SIM001

The --mock-instruments flag uses mock instruments instead of real hardware. Mock values come from mock_config in the station, or can be overridden per-test in the sidecar YAML next to your test file (tests/test_*.yaml).

Station Types #

A station type is a template — one YAML file per type under stations/types/<id>.yaml. It declares the instrument roles (and their type: and driver:) every station of that type must provide, plus the catalog capability ids the type advertises:

# stations/types/voltage_tester.yaml
id: voltage_tester
description: "Basic voltage testing station"
instruments:
  dmm:
    type: dmm
    driver: pymeasure.instruments.keysight.Keysight34461A
  psu:
    type: psu
    driver: pymeasure.instruments.keysight.KeysightE36312A
capabilities:
  - keysight.34461a.dc_voltage
  - keysight.e36312a.dc_source

# stations/types/full_test.yaml
id: full_test
description: "Complete test station"
instruments:
  dmm:
    type: dmm
    driver: pymeasure.instruments.keysight.Keysight34461A
  psu:
    type: psu
    driver: pymeasure.instruments.keysight.KeysightE36312A
  scope:
    type: scope
    driver: drivers.scope.MyScope

There is no required: field on an instrument entry — every role listed under instruments: is required, and any role not listed is omitted by definition. capabilities: is a list of catalog capability ids (strings), not inline capability dicts.

Reference in station instances:

# stations/bench_1.yaml
id: bench_1
name: "Production Bench 1"
station_type: voltage_tester
location: "Lab A"
 
instruments:
  dmm:
    type: dmm
    driver: pymeasure.instruments.keysight.Keysight34461A
    resource: "TCPIP::192.168.1.100::INSTR"
  psu:
    type: psu
    driver: pymeasure.instruments.keysight.KeysightE36312A
    resource: "GPIB0::5::INSTR"

Multiple Stations #

Production Lab #

# stations/prod_bench_1.yaml
id: prod_bench_1
name: "Production Bench 1"
location: "Production Floor, Bay 1"
 
supported_phases:
  - production
 
instruments:
  dmm:
    type: dmm
    driver: pymeasure.instruments.keysight.Keysight34461A
    resource: "TCPIP::192.168.10.101::INSTR"
  psu:
    type: psu
    driver: pymeasure.instruments.keysight.KeysightE36312A
    resource: "TCPIP::192.168.10.102::INSTR"

Development Lab #

# stations/dev_bench.yaml
id: dev_bench
name: "Development Bench"
location: "R&D Lab"
 
supported_phases:
  - development
  - debug
 
instruments:
  dmm:
    type: dmm
    driver: pymeasure.instruments.keysight.Keysight34461A
    resource: "USB0::0x2A8D::0x0101::MY12345::INSTR"
  psu:
    type: psu
    driver: pymeasure.instruments.keysight.KeysightE36312A
    resource: "GPIB0::5::INSTR"
  scope:
    type: scope
    driver: drivers.scope.MyScope
    resource: "TCPIP::192.168.1.200::INSTR"

CI/CD #

# stations/ci_station.yaml
id: ci_station
name: "CI Environment"
description: "For automated testing with --mock-instruments"
 
instruments:
  dmm:
    type: dmm
    mock: true
    catalog_ref: generic_dmm
    mock_config:
      measure_dc_voltage: 3.31
      measure_current: 0.1
  psu:
    type: psu
    mock: true
    catalog_ref: generic_psu
    mock_config:
      measure_voltage: 5.0

Run in CI:

pytest tests/ --station=stations/ci_station.yaml --mock-instruments --uut-serial=CI-TEST

Selecting a fixture at run time #

Stations don't pin a fixture themselves. The active fixture is selected by --fixture=... on the pytest command line (or by a profile that sets it). The plugin validates that the fixture's part_id / part_family matches the active part spec before any test runs.

pytest tests/ \
  --station=bench_1 \
  --fixture=fixtures/power_board_fixture.yaml \
  --uut-serial=SN001

See Fixtures for the pin-to-instrument mapping model.

Capability Declarations #

A station instance (stations/<id>.yaml) does not carry a capabilities: field — capabilities are derived from each instrument's catalog entry when the station loads. See Capabilities for how capability matching works.

If you want to advertise a fixed capability set as part of a type (so concrete stations of that type are guaranteed to provide it), declare it on the station type, not on the instance, as a list of catalog capability ids:

# stations/types/voltage_bench.yaml
id: voltage_bench
description: "Generic DC + AC voltage bench"
instruments:
  dmm:
    type: dmm
    driver: pymeasure.instruments.keysight.Keysight34461A
  psu:
    type: psu
    driver: pymeasure.instruments.keysight.KeysightE36312A
capabilities:
  - keysight.34461a.dc_voltage
  - keysight.34461a.ac_voltage
  - keysight.e36312a.dc_source

To customize the capabilities a specific instrument provides, edit that instrument's catalog YAML (catalog/<vendor>/<model>.yaml) — not the station file.

Validation #

To validate a station file before a run, point pytest at it — a bad config fails fast:

pytest --collect-only --station=stations/bench_1.yaml

A missing required field or a type mismatch raises a pydantic.ValidationError before any test is collected.

Shared Instruments (Multi-UUT) #

When a multi-UUT fixture runs slots in parallel and more than one slot uses the same instrument role, Litmus connects that instrument once and shares it across slots — no extra config. See Multi-UUT testing.

Best Practices #

Use descriptive station IDs — prod_bench_1 not station1
Include location — Helps operators find equipment
Document supported phases — supported_phases: records which phases this bench is set up for; it is shown in the stations UI
Create a CI station — Fully mocked for automated tests; keep one stations/ci_station.yaml with mock: true on every instrument
Version control — Track station YAML changes alongside test code

Common Configurations #

Single DMM #

id: simple_station
name: "Simple DMM Station"
 
instruments:
  dmm:
    type: dmm
    driver: pymeasure.instruments.keysight.Keysight34461A
    resource: "USB0::0x2A8D::0x0101::MY12345::INSTR"

Full Production #

id: production_station
name: "Production Station"
location: "Production Floor"
 
instruments:
  dmm_1:
    type: dmm
    driver: pymeasure.instruments.keysight.Keysight34461A
    resource: "TCPIP::192.168.1.101::INSTR"
  dmm_2:
    type: dmm
    driver: pymeasure.instruments.keysight.Keysight34461A
    resource: "TCPIP::192.168.1.102::INSTR"
  psu:
    type: psu
    driver: pymeasure.instruments.keysight.KeysightE36312A
    resource: "TCPIP::192.168.1.103::INSTR"
  eload:
    type: eload
    driver: drivers.eload.MyELoad
    resource: "TCPIP::192.168.1.104::INSTR"
  scope:
    type: scope
    driver: drivers.scope.MyScope
    resource: "TCPIP::192.168.1.105::INSTR"

Next Steps #

Stations Concept — Understanding stations
Capabilities — Capability matching
Custom drivers — Build a non-VISA driver