Development and Commissioning of the CMS Luminosity Readout System

We discuss the development and commissioning of a luminosity monitor. It is based on hardware that provides realtime histograms of data from the forward hadronic calorimeters in CMS. Measuring the total energy deposition and occupancy in these detectors allows us to calculate the relative instantaneous luminosity of the collider on a bunch by bunch basis, which is useful for machine diagnostics. Once calibrated with measurements from the LHC we will be able to make the first proton-proton inelastic cross-section measurement. Further information on the calculations themselves can be found in [1]. This paper discusses the readout hardware design and implementation.