数字万用表

use lager::{DmmFunction, DmmOptions, LagerBox};

let lager = LagerBox::from_env()?;
let dmm = lager.dmm("dmm1");

pub enum DmmFunction {
    DcVolts, AcVolts, DcCurrent, AcCurrent, Resistance, FourWireResistance,
    Continuity, Diode, Frequency, Period, Capacitance, Temperature,
}

let opts = DmmOptions::new()     // auto-range, the meter's own NPLC and sensor
    .range(20.0)                 // full-scale value in the function's unit
    .nplc(10.0)                  // integration time in power-line cycles
    .sensor("ther:k");           // temperature probe

pub struct DmmReading {
    pub value: Option<f64>,  // None on overload or an open input
    pub unit: String,        // "V", "A", "ohm", "Hz", "s", "F" or "C"
    pub overload: bool,
}

let r = dmm.measure(DmmFunction::DcVolts, &DmmOptions::new().range(20.0).nplc(10.0))?;
let volts = r.value.expect("VBAT over range");
assert!((3.2..3.4).contains(&volts), "VBAT out of tolerance: {volts:.6} V");

use lager::{DmmFunction, DmmOptions, LagerBox};

let lager = LagerBox::from_env()?;
let dmm = lager.dmm("dmm1");

let shunt = dmm.measure(DmmFunction::FourWireResistance, &DmmOptions::new().range(200.0))?;
println!("shunt: {:?} {}", shunt.value, shunt.unit);

let link = dmm.measure(DmmFunction::Continuity, &DmmOptions::new())?;
assert!(!link.overload, "the link is open");