Work out deadband setting instantly with clear inputs, formula shown and shareable results.
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.
Deadband
deadband >= 1.5 x peak-to-peak noise and >= 2 x drift rate / allowed actuations per hour
The actuator chatters on measurement noise, wearing out contacts and valve seats and putting continuous disturbance into the process.
Control accuracy suffers directly: the controlled variable can sit anywhere within the band, so half the band is the minimum steady-state error.