Speaker
Svetozar Kapusta
(Comenius University)
Description
The Alice Detector Controls system is in charge of configuration, control and
monitoring of more than 100 subsystems, consisting of a total numbers of
∼100 000 channels. All controls tasks are performed by a big distributed
system based on PVSS-II. A big emphasis was put into providing software
abstraction layers which hide the complexity and variety of the implemented
hardware access technologies. Together with centralized data management
based on relational database the implemented approach allows for unified
operation of 18 ALICE subdetectors. Several hundreds of MB of configuration
data is needed to setup the PVSSII system, controls devices (power supplies,
cooling plants, ...) and front-end electronics. All channels are monitored at a
rate of 1Hz (or faster). This results in huge data flow which has to be
handled by the controls system and archived in the database for later
processing. Data reduction techniques such as filtering or smoothing were
implemented in all stages of the data acquisition in order to limit the
resulting insertion rate to ∼1000 changes/second. In this paper we describe
the data flow from the configuration database to devices and from
monitored channels into the archive. Data processing at different stages of
the system is explained. We provide also information on data exchange with
external systems (such as data acquisition system, offline, high level
trigger).
Author
Svetozar Kapusta
(Comenius University)
