7.3.9-3 Delaying System Response

Where appropriate, systems that are sensitive to incorrect inputs should be designed to limit the rate at which these inputs can affect the process.

Additional Information:
Limiting the rate at which a system responds to a user's inputs can provide opportunities for the user to detect and correct erroneous material. Methods for delaying system response include programmed limits in the control software, such as maximum ramp rates, and physical limits in plant equipment, such as orifices and dampers, to limit the rate at which processes can respond to inputs. These methods may be used when the system's slower response will not degrade plant operation or safety. These methods should be used with other methods that prevent errors and detect them.