We report on an experiment performed at the Facility for Advanced Accelerator Experimental Tests (FACET) at SLAC National Accelerator Laboratory, in which a new adaptive control algorithm, one with known, bounded update rates, despite operating on analytically unknown cost functions, was utilized in order to provide quasi real time bunch property estimates of the electron beam. Multiple parameters, such as arbitrary RF phase settings and other time-varying accelerator properties, were simultaneously tuned in order to match a simulated bunch energy spectrum with a measured energy spectrum. The simple adaptive scheme was digitally implemented usingMatlab and the Experimental Physics and Industrial Control System (EPICS). The main result is a non-intrusive, non-destructive, real-time diagnostic scheme for prediction of bunch profiles, as well as other beam parameters, the precise control of which are important for the plasma wakefield acceleration (PWFA) experiments being explored at FACET. Show Partial Abstract