1. A method for performing management and diagnostic functions in an advanced process control (APC) system, the method comprising: providing a cloud computing system communicatively coupled by a first communication device to at least one APC control computer; said cloud computing system including an APC management computer having a first processor connected to a first storage device having a first non-transitory machine-readable storage medium storing a data collection module, an APC diagnostics module and a step testing module and said APC management computer is programmed to implement said data collection module, said APC diagnostics module and said step testing module causing said APC management computer to execute: retrieving operating process data from said APC control computer including a plurality of APC history data from an APC history file; performing an iterative step test on said APC system, wherein said iterative step test modifies at least one test parameter of said operating process data and identifies changes to a set of remaining parameters of said operating process data resulting from modification of said test parameter; determining at least one process variable from said iterative step test; generating at least one process model based on said process variable; transmitting said process model to said APC control computer; performing a diagnostic testing on said APC history data; generating at least one new process model setting based on said diagnostic testing; displaying said at least one new process model setting; determining if said at least one new process model setting has been approved; and in response to determining that said at least one new process model setting has been approved: transmitting said at least one new process model setting to said APC control computer; and triggering said APC control computer to install said at least one new process model setting.