Attach quantities

A value such as a tank volume or a raw-water turbidity is an S223 property on equipment, a point, or a connection. Units and quantity kinds are QUDT terms from plumb.qudt.

from plumb import Model, connect
from plumb.qudt import QuantityAmount as Q, quantity_kinds, units
from plumb.watr import Pump, Tank, enums
from plumb.watr.drinking_water import CoagulationStage

values = enums.values
model = Model("urn:example:quantities#")
with model:
    intake = Pump("intake-pump")
    coagulation = CoagulationStage("coagulation")
    clearwell = Tank("clearwell")
raw_water = connect(intake, coagulation.inlet, name="raw-water")
connect(coagulation.outlet, clearwell, name="coagulated-water")

<ConnectionHandle coagulated-water: coagulation-outlet -> clearwell>

Attach one quantity

.quantity() creates and attaches a property with a value, unit, and kind:

volume = clearwell.quantity(
    "clearwell-volume",
    5_000,
    unit=units.M3,
    kind=quantity_kinds.Volume,
    has_aspect=[values.Aspect_Nominal],
)
volume, volume.has_value, volume.has_unit

(<QuantifiableProperty 'clearwell-volume'>, 5000.0, <term M3>)

The unit must match the kind’s dimensions:

try:
    clearwell.quantity("bad-volume", 5, unit=units.KiloGM, kind=quantity_kinds.Volume)
except ValueError as error:
    print(error)

bad-volume: unit and quantity kind are incompatible

capability= picks the property class:

Capability	Use
"static" (default)	a fixed value
"observable"	a measured value; see .sensor()
"actuatable"	a writable setpoint

Add Aspect_Nominal yourself for a nominal value.

Qualify a stream quantity

A quantity on a connection describes what flows in it. Name the medium and, for a constituent, the substance:

toc = raw_water.quantity(
    "raw-organic-carbon",
    3.5,
    unit=units.MilliGM_PER_L,
    kind=quantity_kinds.MassConcentration,
    of_medium=values.Water_Freshwater,
    of_substance=values.Constituent_OrganicCarbon,
)
toc.of_medium, toc.of_substance

(<enum Water-Freshwater>, <enum Constituent-OrganicCarbon>)

The property moves to the concrete pipe when the model resolves. Ports and named points accept quantities the same way.

The medium of a property

223P requires a property’s of_medium to be compatible with the medium of the pipe, point, or equipment it is on. Resolution uses that:

• Without of_medium, the property takes its host’s resolved medium.

• With of_medium, the solver keeps the host’s medium compatible, and check() reports a conflict.

Water_Freshwater above fits the raw-water pipe’s Fluid_Water. Fluid_Air would not; How connections are resolved defines compatible media:

with Model("urn:example:conflict#") as other:
    stage = CoagulationStage("coagulation")
    sump = Tank("sump")
drain = connect(stage.outlet, sump, name="drain")
drain.quantity(
    "drain-temperature", 15, unit=units.DEG_C, kind=quantity_kinds.Temperature,
    of_medium=values.Fluid_Air,
)
report = other.check()
print(report.status)
print(report.issues[0].labels[-1])

unsatisfiable
drain-temperature: ofMedium Fluid-Air must be compatible with the medium of drain

Attach a plain value

When no QUDT quantity kind fits, use S223’s Property with a literal:

from plumb.watr import Property

permeability = Property(
    "water-permeability",
    label="Water permeability coefficient [m/(Pa·s)]",
    has_value=4.2e-12,
    has_aspect=[values.Aspect_Nominal],
    model=model,
)
coagulation.has_property.add(permeability)

QUDT has no kind for reverse-osmosis water permeability (M-PER-SEC-PA), hence the plain Property above.

Limits

S223 and WaTr describe one nominal, untimed value per property. They cannot distinguish operating points, samples, or scenarios of the same stream. That needs a companion ontology defining the operating point, its time or scenario, whether a value is nominal, calculated, or measured, and the composition basis.

Next

Define and apply property sets groups quantities into a reusable schema.