Last update: Apr 1, 2000
Speaker: Lars EwellWhen the Relativistic Heavy Ion Accelerator begins operation early in 2000, the PHENIX detector will begin to acquire physics events. Consisting of eleven different subsystems and approximately 300,000 readout channels, the control system for this detector needs to be large and robust. That system, the PHENIX Ancillary Control System, is divided into low voltage and high voltage control.
The high voltage system uses the Experimental Physics and Industrial Control System (EPICS) to control individual channels. The final channel count is estimated to be 3,500 and will be multiplexed to allow for the 300,000 readout channels referred to above. This will involve four MVME 167 Input Output Controllers running VxWorks that will function as channel access servers. The Motif Editor and Display Manager (MEDM) channel access client is resident on a cluster of Sparc workstations. The hardware controlled by the EPICS system will mainly be LeCroy 1458 high voltage power supplies which will contain a combination of 1461, 1469 and 1471 high voltage modules.
In addition to the EPICS control, a group of C++ classes was created to enable connection between the VxWorks based EPICS high voltage records and the Objectivity database. This is achieved through the EPICS extension ``ezca'' (easy channel access).
The Advantech ADAM 5000 distributed data acquisition module is central to the PHENIX low voltage control system. These modules are located remotely within the electronics racks and allow for control of the rack power, as well as the ability to monitor alarms, temperatures and other analog and digital inputs. Communication is done via RS485 enabling long distances between modules. An OPC (Object linking and embedding for Process Control) server running on a Windows NT platform allows for control the individual modules. In addition, the OPC standard makes for ease of communication between different platforms.
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