A closed loop/semi-closed loop infusion system provides therapy modification and safeguards against the over-delivery or under-delivery of insulin. A glucose sensor system is configured to obtain a measured blood glucose value. A controller is operationally connected with the glucose sensor system and configured to compare the measured blood glucose value to a target blood glucose value and adjust a therapy delivery parameter if the measured blood glucose value is not consistent with the target blood glucose value, wherein the adjusted therapy delivery parameter is limited to be within a boundary. Thereafter, a delivery system delivers therapy at the adjusted therapy delivery parameter.
