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Discovery and device assignment

How instruments are found, classified, and rebound after hardware swaps.

Auto-discovery

Sync: Discovery::visa()?.scan()?
Async (tokio feature): AsyncDiscovery::visa()?.scan().await?

using InstrumentComponents.Visa;

var catalog = VisaDiscovery.Create().Scan();

Both enumerate (via the VISA resource manager):

  • ?*INSTR (all instruments)
  • USB?*::INSTR
  • GPIB?*INSTR
  • ASRL?*INSTR (serial)

USB and GPIB require no manual address. TCPIP/LXI usually does:

Discovery::visa()?
    .manual_address("TCPIP0::192.168.0.42::INSTR")
    .scan()?;

using InstrumentComponents.Visa;

var catalog = VisaDiscovery.Create()
    .ManualAddress("TCPIP0::192.168.0.42::INSTR")
    .Scan();

Probe policy

Controls how aggressively devices are classified during scan:

Policy Behavior
ReadOnly (default) Registry + *IDN? + benign state queries
None Registry + *IDN? only
Full ReadOnly plus :MEAS:VOLT:DC? (triggers acquisition) 
let catalog = Discovery::visa()?
    .probe_policy(ProbePolicy::ReadOnly)
    .scan()?;

using InstrumentComponents.Probe;
using InstrumentComponents.Visa;

var catalog = VisaDiscovery.Create()
    .WithProbePolicy(ProbePolicy.ReadOnly)
    .Scan();

Listing devices by type

for dev in catalog.devices_by_kind(InstrumentKind::Dmm) {
    println!("{} — {}", dev.device_id(), dev.address.raw);
}

Serialize for a UI:

let json = serde_json::to_string_pretty(catalog.devices())?;

using InstrumentComponents.Kind;

foreach (var dev in catalog.DevicesByKind(InstrumentKind.Dmm))
{
    Console.WriteLine($"{dev.GetDeviceId()} — {dev.Address.Raw}");
}

Instrument replacement

DeviceId is derived from manufacturer + model + serial (falls back to VISA address):

let id = dev.device_id();
// save `id` in app config
let device = catalog.reconnect_by_identity(&id)?;
let dmm = device.open_dmm()?;

Persist DeviceId from a discovered device, rescan after a swap, and open by identity — the VISA address may change but a serial-based ID stays stable. See dotnet/examples/AssignInstruments.

User overrides

Force kinds when classification is wrong:

Discovery::visa()?
    .override_kinds("GPIB0::10::INSTR", vec![InstrumentKind::Dmm])
    .scan()?;

using InstrumentComponents.Kind;
using InstrumentComponents.Visa;

var catalog = VisaDiscovery.Create()
    .OverrideKinds("GPIB0::10::INSTR", [InstrumentKind.Dmm])
    .Scan();

Adding models to the registry

Edit crates/instrument-core/data/model_registry.toml and regenerate shared tables. See the repo CONTRIBUTING.md.