Deadband Setting Calculator

Work out deadband setting instantly with clear inputs, formula shown and shareable results.

About Deadband Setting Calculator

A deadband must exceed the measurement noise, otherwise noise alone commands the actuator. It must also be wide enough that the process drift rate divided by the band gives an acceptable cycling frequency, which is what protects valves, relays and compressors from short-cycling.

Formula

Deadband

deadband >= 1.5 x peak-to-peak noise and >= 2 x drift rate / allowed actuations per hour

Worked example

With the default values below, Deadband Setting Calculator returns Recommended deadband of 1.20. Change any input above and every figure here is recalculated in your browser.

Inputs used

Measurement noise (peak to peak): 0.8 units
Sensor resolution: 0.1 units
Actuations tolerated per hour: 30 actuations/h
Process drift rate: 2 units/h

Results

Recommended deadband: 1.20 units
Expected actuations per hour: 3.33 actuations/h
Minimum deadband from noise: 1.20 units
Assessment: Actuation rate within the target

Step by step

1Values used
2Deadband
3Recommended deadband= 1.20 units
4Expected actuations per hour= 3.33 actuations/h
5Minimum deadband from noise= 1.20 units
6Assessment= Actuation rate within the target

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What goes wrong with too narrow a deadband?

The actuator chatters on measurement noise, wearing out contacts and valve seats and putting continuous disturbance into the process.

And too wide?

Control accuracy suffers directly: the controlled variable can sit anywhere within the band, so half the band is the minimum steady-state error.