If the operators are not active, they might be unaware of risky situations. The system can detect hazards, and switch to automated response when facing threats.

Grace time

The grace time is the time when automatic intervention is required, namely, in which the system should switch from manual control to automated. This chart illustrates how to compute the grace time.

Steps

• During the operation, the system should check changes in critical parameters, and compute the trends.
• The time when the parameter value reaches the critical value is the time of predicted incidence, marked by Tc.
• For each of the critical parameters, the knowledge base should include an estimate of the critical time, the minimal time in which the system can respond automatically
• The grace time, (the time when automatic intervention is required) is
      Ta = Tc - Critical-Time

Updated on 16 Mar 2017.