The control system for the CMS tracker front-end

The CMS Tracker uses complex, programmable embedded electronics for the readout of the Silicon sensors, for the control of the working point of the optical transmitters, for the phase adjustment of the 40 MHz LHC clock and for the monitoring of the voltages, currents and temperatures. In order to establish reliable, noise-free communication with the outside world the control chain has been designed to operate over a ribbon of optical fibers. The optical links, the Front End Controller board that carries their support electronics, the Clocking and Control Unit module receiving the signals over the high-speed link and fanning them out to the front-ends have recently become available. A multi-layered software architecture to handle these devices, and the front-ends, in a way transparent to the end-user, interfaced to an Oracle database for the retrieval of the parameters to be downloaded with the intent of building and operating a small-scale prototype of the control system for the CMS Tracker. The paper describes the components, hardware and software, of the prototype Control System developed for the CMS Tracker.