The Spallation Neutron Source (SNS) is an accelerator-based neutron source in Oak Ridge, Tennessee, USA, that provides intense pulsed neutron beams for scientific research and industrial development. The accelerator is designed to deliver a 1.0 GeV, 1.4 MW proton beam onto a liquid mercury target to generate pulsed neutrons. The accumulator ring combines more than a thousand pulses from the linac into one short and intense pulse of up to 1.5e14 protons with a typical peak current of over 50 amperes and a bunch length of about 0.7 microseconds. This talk reviews the beam instrumentation implemented at SNS and how it interacts with the Machine Protection System. Examples will be given of various systems, such as the differential current monitor, and our operational experience including noise issues. The necessity of these systems will be discussed as well as ongoing research to minimize long term damage to accelerator system elements such as the superconducting cavities.