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Signals and PLC · Glossary

What is ADC Resolution?

bitsSignals and PLC

ADC resolution is the number of bits an analog to digital converter uses, which sets the smallest signal change it can see.

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ADC Resolution Explained

An n bit converter divides its range into 2ⁿ steps. More bits give finer steps, but accuracy also depends on noise, linearity and drift.

Industrial analog inputs are commonly 12 to 16 bits.

ADC Resolution Formula

Step = Range ÷ 2ⁿ
nnumber of bits
Rangeinput span
Example: 16 bits over 0 to 20 mA: 20 ÷ 65,536 ≈ 0.31 µA per step.
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Calculators for ADC Resolution

CalculatorADC Resolution CalculatorFree online calculator with formula and worked example.CalculatorAnalog Scaling CalculatorFree online calculator with formula and worked example.

Frequently Asked Questions

What is ADC Resolution?

ADC resolution is the number of bits an analog to digital converter uses, which sets the smallest signal change it can see.

Is resolution the same as accuracy?

No. A 16 bit card can still have an accuracy of 0.1 % of span.

How many bits do I need?

Enough that one step is well below the accuracy you need; 12 bits gives 4096 steps, often sufficient.

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