Engineering Toolbox — Van Rogers

4–20 mA Loop & Scaling Calculator

ENGINEERING RANGE

CHARACTERIZATION PLC RAW COUNT RANGE (AT 4 mA / AT 20 mA)

SIGNAL — ENTER ANY ONE FIELD

mA

PERCENT

ENGINEERING VALUE

RAW COUNTS

SIGNAL %	mA	RAW COUNTS	ENGINEERING VALUE

Linear: EU = LRV + (URV − LRV) × (mA − 4) / 16. Square root: flow % = √(signal %) — used with differential-pressure flow elements.

RTD Calculator — PT100 / PT1000

ELEMENT TEMPERATURE → RESISTANCE

RESISTANCE → TEMPERATURE

Callendar–Van Dusen, IEC 60751: A = 3.9083×10⁻³, B = −5.775×10⁻⁷, C = −4.183×10⁻¹² (below 0 °C). Valid −200 °C to +850 °C.

Thermocouple Quick Reference — ANSI MC96.1

TYPE	CONDUCTORS (+ / −)	RANGE	LEADS (+ / −)	JACKET
K	Chromel / Alumel	−200…1260 °C	Yellow / Red	Yellow
J	Iron / Constantan	0…760 °C	White / Red	Black
T	Copper / Constantan	−200…370 °C	Blue / Red	Blue
E	Chromel / Constantan	−200…870 °C	Purple / Red	Purple
N	Nicrosil / Nisil	−200…1300 °C	Orange / Red	Orange
R / S	Pt-Rh / Pt	0…1480 °C	Black / Red	Green
B	Pt-30Rh / Pt-6Rh	870…1700 °C	Gray / Red	Gray

Negative lead is red in all ANSI types. Always match extension wire type to the thermocouple — mixed types create unintended junctions and measurement error.

Pressure Converter

inH₂O referenced at 68 °F (27.681 inH₂O = 1 psi).

Temperature Converter

Ohm's Law / Power Calculator

ENTER ANY TWO VALUES — THE REST CALCULATE AUTOMATICALLY

VOLTAGE (E)

CURRENT (I)

RESISTANCE (R)

POWER (P)

E = I × R · P = E × I · P = I² × R · P = E² ÷ R

Three-Phase Power Calculator

LINE-TO-LINE VOLTAGE (V) POWER FACTOR (0–1) ENTER ANY ONE — OTHERS CALCULATE

AMPS

kW

kVA

kVA = √3 × V × I ÷ 1000 · kW = kVA × PF · I = kW × 1000 ÷ (√3 × V × PF)

Voltage Drop Calculator — Copper

CONDUCTOR SIZE (AWG)

ONE-WAY LENGTH (ft)

LOAD CURRENT (A)

SYSTEM

SOURCE VOLTAGE

1φ/DC: V_d = 2 × L × R × I ÷ 1000 · 3φ: V_d = √3 × L × R × I ÷ 1000. R from NEC Ch. 9 Table 8 (uncoated copper, DC Ω/kft). NEC recommends ≤ 3 % branch-circuit drop.

Resistor Color Code — Decoder

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Resistor Color Code — Finder

RESISTANCE

TOLERANCE

PID Loop Simulator / Tuner — FOPDT Process

PV SP OUT (CV)

CONTROLLER

GAIN Kc1.0

RESET Ti (s)20

RATE Td (s)0

PROCESS MODEL (FOPDT)

PROC GAIN K1.0

TIME CONST τ (s)20

DEAD TIME θ (s)3

Sim runs 5× real time. Ideal-form PID, derivative on PV, anti-reset-windup. Ti = 0 disables integral. Suggested tuning is SIMC (Skogestad): Kc = τ / (2·K·θ), Ti = min(τ, 8θ). Intended as a field starting point; final tuning should be validated on the actual loop.