1. A medical pump system that provides advance guidance to a user regarding existence of a valid input range for a pump programming parameter, comprising: an input device for entering a value of a pump programming parameter; a memory for storing constraints related to the pump programming parameter; and a processor in communication with the memory and the input device, the processor being operable to utilize the constraints to determine and generate a signal indicating whether a valid input range exists for a to-be-entered value of the pump programming parameter.