Instrumentation & Controls

Linear voltage signal to temperature. Over-range is not clamped.

Where a voltage signal sits in its configured span. Defaults to 0–10 V. Not clamped.

Voltage across a 250 Ω HART / PLC current-loop resistor.

Voltage drop across series loop devices and remaining supply voltage.

Raw PLC counts that represent 4–20 mA, then the configured engineering pressure.

Linear transmitter current to process value. Engineering fields are pressure; use generic linear scaling for other quantities.

Where a live-zero current sits in its configured span. Over/under-range is not clamped.

Unipolar ADC: V = counts × Vref / (2^N − 1). Endpoints are 0 and full-scale.

Loop voltage drop, remaining headroom, and how the installed resistance compares with Rmax at 20 mA (INST-10).

Actual minus expected, as current, percent of span, and percent of reading.

Engineering units per ADC count and per milliamp of a 16 mA live span.

Voltage drop from cable current and resistance.

Two-wire DC voltage drop from one-way length and conductor resistance per unit length.

Normalized square-root flow: Q = Qmax √(ΔP / ΔPmax). Not an orifice sizing tool (see FLUID-23).

Expected transmitter current for a known process pressure.

Estimate flow from ΔP across an orifice, a known K, or a valve Cv. Pick the model explicitly.

Gauge pressure from a liquid column. Height may be signed.

Zero shift at LRV and span/gain error between measured and reference endpoints.

Linear 4–20 mA level. Optional tank height gives fill fraction and remaining headroom. Not a tank-volume geometry tool.

Generic linear scale: any signal range onto any engineering range. Both sides are dimensionless so the same tool covers mA, V, and counts.

Convert between voltage, current, and power for a DC, PoE, or unity-PF load.

Where a measured loop current sits relative to live zero/full scale, with NAMUR-style band context — not a device verdict.

Maximum series resistance a 4–20 mA loop can tolerate at full-scale current.

Solve for voltage, current, resistance, or power from any two of the four.

Incompressible flow through an orifice from differential pressure. Not a metering-standard calculation.

Controller error e = SP − PV (reverse) or PV − SP (direct). Dimensionless engineering units.

One discrete PID step. Not a running controller. Simple anti-windup holds the integral when the output saturates.

Overshoot, undershoot, last-sample steady-state error, and peak |PV − SP| from observed samples. Not rise/settling time without a time base.

Kp ↔ proportional band (PB = 1/Kp as a fraction), Ti ↔ integral rate, Td ↔ derivative rate. Vendor conventions differ.

PLC raw analog input to pressure. Default raw range 0–32767.

Raw PLC output count for a desired engineering value. Integer rounding matches INST-13.

Convert a pressure difference to fluid head, or head to pressure.

How much extra series lead resistance shifts the indicated IEC 60751 temperature.

IEC 60751 Callendar–Van Dusen platinum RTD. Default R0 = 100 Ω (Pt100).

Inverse of INST-22. IEC 60751 platinum characteristic.

Combine independent error terms by RSS or worst-case absolute sum. RSS is not always the right spec method.

Indication minus reference across two or three points: max absolute, average, percent span, percent reading.

Theoretical LSB in engineering units for an N-bit unipolar converter over a pressure range.

Sum two or more resistances in series.

Current from measured shunt voltage and known shunt resistance.

Shunt resistance from measured voltage and current.

Shunt measurement from millivolt drop and current. Same Ohm’s-law math as Rectifier Circuit Resistance, labeled for shunt work.

Voltage drop across a shunt from current and resistance. Display in mV or V.

Output = √(input fraction). Use this to see whether square-root is applied in the transmitter or the PLC.

NIST ITS-90 inverse polynomials with cold-junction compensation. Types K, J, T, E, N, R, S.

Pressure transmitter span, midpoint, and engineering units per milliamp of a 16 mA live span.

Linear correction Corrected = a × Measured + b from two calibration points.

Calculate voltage drop or IR drop from current and resistance.

Nearest integer count using round-half-away-from-negative-infinity (ECMA Math.round).