Control and Monitoring System for the HADES RPC detector

The control and monitoring system designed for the front-end electronics of the HADES RPC detector, installed at GSI Helmholtz Centre for Heavy Ion Research GmbH (Darmstadt, Germany), is described. This new detector for the time-of-flight detection system of HADES contains 1116 electrically shielded RPC cells and covers an active area of about 8 m2. The slow control system controls/monitors about 6500 variables and is being implemented using the experimental physics and industrial control system (EPICS) software tool kit. A MEDM graphical interface is being developed for the client system. The control and monitoring system attends four different systems: front-end electronics, low voltage system, detector and gas system. Each system communicates the control/monitoring system via a different and independent hardware interface, but the user interacts with a common software application that interfaces all systems. The front-end electronics has 2232 electronic channels that require threshold setting of the LTC2620 chips via serial peripheral interface (SPI). The low voltage system monitors currents and voltages via 1-wire bus. The detector is equipped with controllable switches and the gas system requires the control and monitoring for the gas flows. Temperature of all systems is sensed using the DS18B20 chip. The data acquisition system interacts with the main part of the systems via system-on-chip ETRAX computers (equipped with Ethernet port) that run EPICS IO servers over an embedded LINUX kernel.