A DCS module execution time of 0.1 second should be fast enough. The bigger question may be whether the measurement, final control element, and feedback loop is fast enough. A feedforward action to preemptively change the final control element by an amount that corresponds to a required correction should be considered. If the final control element is pneumatically actuated valve or damper, feedforward action won’t save the day. The final control element needs to fast enough to significantly respond within the module execution time.