The control system for the front-end electronics of the ALICE time projection chamber

The ALICE detector is a dedicated heavy-ion detector currently built at the Large Hadron Collider (LHC) at CERN. The detector control system (DCS) covers the task of controlling, configuring and monitoring the detector. One sub-system is the control system.for the Front-end electronics of the time projection chamber (TPC). It controls in total 216 readout systems with 4356 Front-End Cards serving roughly 560 000 channels. The system consists of a large number of distributed nodes in a layer-structured hierarchy. The low-level node controlling the Front-end electronics is an embedded computer system, the DCS board, which provides the opportunity to run a light-weight Linux system on the card. The board interfaces to the Front-end electronics via a dedicated hardware interface and connects to the higher DCS-layers via the DIM communication framework over Ethernet. Since the experiment will be running in a radiation environment, fault tolerance, error correction and system stability in general are major concerns. Already the low level devices carry out intelligent error handling and act automatically upon several conditions. This paper presents the architecture of the system, the application of the DCS board and experiences from integration tests.