Struct FopdtProcess 

pub struct FopdtProcess { /* private fields */ }

A first-order-plus-dead-time process model, advanced one tick at a time.

Uses the exact analytical solution for a first-order lag driven by a piecewise-constant (zero-order-hold) input over each tick – pv_new = pv*decay + (1-decay)*(bias + gain*mv_effective), decay = exp(-tick_interval_s / time_constant_s) – rather than numerically integrating an ODE every tick, as Model/ProcessModelOPC.py’s scipy.integrate.odeint call does. This is not an approximation: it is the closed-form solution of tau * d(pv)/dt = -(pv - pv0) + gain*(mv - mv0) for an input held constant over [t, t+dt], which is exactly what “the controller wrote this MV and it stays there until the next write” means physically. Cross-checked numerically (in a disposable scratch script, not part of this repo) against the reference script’s own odeint-based integration across a range of gain/tau/dt combinations before relying on it – the two agree to within odeint’s own numerical tolerance (~1e-5).

Implementations

impl FopdtProcess

pub fn new( config: FopdtConfig, initial_pv: f32, initial_mv: f32, seed: u64, ) -> FopdtProcess

Builds a process starting at rest: initial_pv is assumed to already be the correct steady-state PV for initial_mv (i.e. nothing changes until a FopdtProcess::set_mv call moves the MV away from initial_mv). seed makes the noise sequence reproducible – the same config/seed/write sequence always produces the same PV sequence (on a given platform and rand version; see [rand::rngs::StdRng]’s own caveat that its algorithm is not a portability guarantee across those).

pub fn pv(&self) -> f32

The current PV, as of the last FopdtProcess::step call (or initial_pv, if step has never been called).

pub fn mv(&self) -> f32

The most recently recorded MV (see FopdtProcess::set_mv) – not delayed; this is what a real DCS’s own MV readback tag would report immediately. Only the PV’s response to it is delayed.

pub fn set_mv(&mut self, mv: f32)

Records a new controller output, effective from the next FopdtProcess::step call onward (after passing through the dead-time delay line, if configured).

pub fn step(&mut self) -> f32

Advances the process by one tick_interval_s, using whichever MV was most recently recorded via FopdtProcess::set_mv – delayed by dead_time_s, if configured – as the input, and returns the resulting PV (including noise, if configured).

Trait Implementations

impl Debug for FopdtProcess

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.