Dealing with deadtime

Deadtime is literally a period of time when nothing happens, no matter what actions have been taken. In control, deadtime, or delay, is a time period between time of a change in control signal (control variable) and time of a change in the process output. The deadtime starts at the moment the control signal has been changed (manually or automatically) and it does not end until the corresponding change can be seen in the process output. Deadtime provides a fundamental limitation for achievable control performance and this needs to be considered when designing control for deadtime dominated systems. Deadtime sets limits both for stability and control performance. Yet, by treating it properly, deadtime can be compensated using appropriate control design techniques and it does not have to be a nuisance for profitable control.