BAS Software SolutionsTechnical workflow software
Flow · Interactive Instrumentation Guide
Linear Flow Transmitter
Increase or decrease flow through a pipe and see a proportional 4–20 mA signal.
Custom process schematic · not to scale · blue H connection / orange L connection, where applicable.
Equation and live calculation
I_ideal = 4 + 16(Q − LRV)/(URV − LRV)
Live substitution appears when the demonstration loads.
PV = process value; LRV/URV = lower/upper range values; I = current in mA. Pressure calculations use kPa internally. Selected units apply to inputs, limits, diagrams, and readouts; changing units converts the same physical values without changing the current. Tank calculations use meters internally; z is positive above the bottom tap. ρ = 1000 × specific gravity in kg/m³; g = 9.80665 m/s². H in tank equations means measured height, not the H port. Entered LRV/URV define the current scaling; calculated empty/full tank DP values are reference checks. Set and Reset Points define switch operation; deadband is their absolute difference. Temperature reference equations use °C internally. Mercury pressure units use conventional NIST conversion factors. Vacuum entries are negative gauge pressure; the absolute-pressure readout remains nonnegative. Models assume ideal instantaneous response. Displayed current is limited to the nominal 4–20 mA range: I_display = clamp(I_ideal, 4, 20), where clamp holds a value at its lower or upper limit. This teaching limit does not reproduce manufacturer-specific saturation or alarm currents.
Where it is used
An ideal transmitter whose output is already linear in volumetric flow, such as a configured magnetic flowmeter.
What the demonstration shows
The output follows flow fraction directly. Unlike raw differential pressure, this signal needs no square-root extraction.
Common mistake to avoid
This simulator represents scaling only. Actual meter selection depends on conductivity, fluid, installation, and operating conditions.
Model assumptions
Ideal proportional transfer with no damping or measurement error. The teaching model limits current to 4–20 mA; manufacturer-specific saturation and fault-current logic are excluded. Display-unit changes preserve the same physical values.
Technical references
Yokogawa — Square-root extractionEducational model. Consult the instrument manual for installation, configuration, limits, and approved test procedures. No connection to live plant equipment is made.