Why does this tool handle 1-5V and 2-10V even though the page is called 0-10V Scaling Calculator?

0-10V is the head term most engineers search for, but real field work often includes related live-zero voltage families such as 1-5V and 2-10V. Treating them together makes the tool more useful while still serving the core 0-10V intent.

When should I worry about loading error on a voltage signal?

Worry when the source is not a near-ideal low-impedance output, when a series resistor or isolator sits upstream, or when the receiver input impedance is relatively low. In those cases the delivered voltage can be lower than the commanded voltage.

Should I clamp out-of-range values or preserve extrapolated results?

Clamp when operator displays or command outputs should stay inside the declared signal family. Preserve extrapolated values when troubleshooting requires visibility into how far the signal has drifted beyond calibration.

Can this handle reverse-acting scaling?

Yes. If the engineering maximum is numerically lower than the engineering minimum, the tool keeps the slope negative and treats the signal as reverse acting.

Does this replace the analog input or actuator manual?

No. It accelerates scaling, checkpoint planning, and loading analysis, but you still need the device manual to verify impedance, filter behavior, deadband, special command zones, and any device-specific nonlinearity.

Home / Tools / 0-10V Scaling Calculator

Signal Utility

0-10V Scaling Calculator

0-10V Scaling Calculator converts voltage signals into engineering units and back, handles 1-5V and 2-10V families, estimates loading error, and generates calibration checkpoints.

Signal Family, Process Range, And Interface Setup

Voltage Family Presets

0 to 10V

Signal Minimum

Signal Maximum

Engineering Presets

Reusable process ranges

Engineering Min

Engineering Max

Unit Label

Source Resistance

Use 0 ohm to model an ideal low-impedance analog output. Raise this when a conditioning stage or divider exists upstream.

Receiver Input Impedance

Use the actual analog input impedance to estimate loading error at the card or conditioning stage.

Output Handling

Extrapolate to preserve diagnostic visibility. Clamp when operator displays or command outputs must remain inside the declared signal family.

Signal Voltage Input (V)

Enter the source or commanded analog voltage you want to interpret.

Signal-family caution

Treat 0-10V as an interface family, not a guarantee of zero loading error. Confirm receiver impedance when signals travel through isolators or conditioning cards.

Live Scaling Result

Awaiting valid input

Scaled engineering value

Enter a signal voltage

Use this to translate a voltage signal at the analog interface into an engineering value.

Span Position

Calculated from the declared voltage low and high values.

Engineering Per 1 V

10 %

Signed slope shows whether the scaling is direct acting or reverse acting.

1% Span Voltage

0.1 V

Useful for sanity checks during trim, setpoint generation, and analog output verification.

Receiver Voltage After Load

0 ohm source into 100,000 ohm receiver

Interpretation

Pick a voltage family, define the engineering span, and solve from either an actual signal voltage or a target process value.

Interface Loading Check

Voltage Drop

Loading Error

Receiver Current

This is a simple divider model. It is most useful when a non-ideal source, series resistor, or conditioning stage can attenuate the voltage before it reaches the analog input.

Scaling Equations

ENG = 0 + ((V - 0) * 100 / 10)

V = 0 + ((ENG - 0) * 10 / 100)

V_receiver = V_source * (R_input / (R_source + R_input))

Calibration And Verification Checkpoints

% Span	Source Voltage	Engineering Value	Receiver Voltage	Receiver Engineering
0%	0 V	0 %	0 V	0 %
25%	2.5 V	25 %	2.5 V	25 %
50%	5 V	50 %	5 V	50 %
75%	7.5 V	75 %	7.5 V	75 %
100%	10 V	100 %	10 V	100 %

Generated Logic Snippet

// Generic ST-style voltage scaling logic
eng_raw := 0 + ((v_in - 0) * 100 / 10);
eng_out := eng_raw; // preserve extrapolated value for diagnostics

v_cmd := 0 + ((eng_in - 0) * 10 / 100);
// optional: clamp v_cmd to the declared voltage range

// Optional loading check when the source is not ideal:
// v_receiver := v_cmd * (r_input / (r_source + r_input));

Keep the ideal scaling formula separate from the loading model. First define the voltage family correctly, then decide whether interface impedance needs to be modeled in code or verified during commissioning.

Assumptions & Usage Notes

This tool assumes a linear source, a linear receiver, and a simple resistive loading model. It does not replace final verification of device deadband, special command zones, filter behavior, or vendor-specific analog input scaling rules.

Equation And Interface Reference

These are the core relationships behind voltage scaling, inverse command generation, and receiver loading checks.

Topic	Expression	Meaning
Voltage To Engineering	ENG = EUlow + ((V - Vlow) x (EUhigh - EUlow) / (Vhigh - Vlow))	Maps a measured or commanded analog voltage into the declared engineering span.
Engineering To Voltage	V = Vlow + ((ENG - EUlow) x (Vhigh - Vlow) / (EUhigh - EUlow))	Calculates the source voltage required to represent a target engineering value.
Voltage Loading	Vreceiver = Vsource x (Rinput / (Rsource + Rinput))	Shows how a non-ideal source and finite receiver impedance can attenuate the signal before it reaches the analog input.
Signal Resolution	1% span = (Vhigh - Vlow) / 100	Useful for trim sheets, AO checkout, actuator command validation, and signal sanity checks.

Voltage Family Matrix

Pick the signal family that matches the job-to-be-done before you touch the engineering range or PLC logic.

Signal Family	Common Use Case	Strengths	Critical Cautions
0-10V	General analog outputs, drives, dampers, process signal interfaces	Simple unipolar span with wide familiarity across PLC and BMS hardware	No live zero. A 0V reading alone does not distinguish true process zero from a dead source.
1-5V	Shunted 4-20mA loops and legacy voltage-style process inputs	Keeps a live-zero concept while using a voltage receiver	Treat it like a translated current loop, not a plain 0-5V signal.
2-10V	Actuators, VAV control, and live-zero voltage control signals	Maintains a recognizable active low-end voltage	Different devices can assign special meaning to 0V, 2V, and 10V.
Plus/Minus 10V	Motion references, bipolar speed commands, and servo interfaces	Supports signed command ranges cleanly around a zero center	Signed polarity errors are easy to miss during checkout if the intended direction is not explicit.

Field Workflow And Code Strategy

Separate three concerns: ideal scaling, receiver loading, and device-specific behavior. That makes commissioning faster and faults easier to isolate.

eng_raw := eu_low + ((v_in - v_low) * (eu_high - eu_low) / (v_high - v_low));
eng_out := LIMIT(MIN(eu_low, eu_high), eng_raw, MAX(eu_low, eu_high));

v_cmd := v_low + ((eng_in - eu_low) * (v_high - v_low) / (eu_high - eu_low));
v_receiver := v_cmd * (r_input / (r_source + r_input));

Recommended workflow

First confirm the declared voltage family. Then validate the engineering range and clamp policy. Only after that should you model source resistance and receiver impedance. If you mix those steps together, it becomes hard to tell whether the error is coming from wrong scaling, wrong wiring assumptions, or a loading issue at the analog interface.

Worked Example

Suppose an actuator reference uses 2-10V for a 0 to 100% command span. A desired output of 75% requires 8.0 V from the source.

If the source has 500 ohm series resistance and the receiver input is only 10 kohm, the receiver will not actually see the full 8.0 V. The delivered voltage will be attenuated, which shifts the actuator command lower than expected even though the ideal scaling equation was correct.

That is why this tool exposes both the ideal scaling result and the loaded receiver voltage. The real field problem is often not the slope itself, but the interface around the slope.

Why This Tool Matters

Voltage analog signals look deceptively simple. Engineers often remember the linear formula but forget that not every source is ideal and not every receiver is truly high impedance.

That leads to a subtle class of errors: the math in the PLC is correct, the number on the commissioning sheet is correct, yet the hardware still receives the wrong voltage because the interface is loading the source.

This page is built to catch exactly that kind of mistake. It treats voltage scaling as an interface problem, not just a unit-conversion problem.

Frequently Asked Questions

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