New CLAS Level1 Trigger System

During G12 run preparations on spring 2008 we decided to upgrade photon part of CLAS Level1 trigger system using CAEN v1495 logic unit. Eventually those efforts resulted in full Level1 system replacement: 6 level1 router boards and event processor board were replaced with one single v1495 unit equipped with 2 extra daughter modules. Trigger was commissioned during first phase of G12 run, last significant change was applied April 20, 2008. Most of the job was completed by Ben Raydo from Fast Electronics group. Valery Kubarovsky and Pawel Nadel-Turonski made generic trigger design and conducted trigger testing. Sergey Boyarinov, Ivan Bedlinskiy, Nerses Gevorgyan and Hovanes Egiyan integrated new hardware and software components into CLAS online and slow control systems. Technical assistance was provided by Fast Electronic Group and CODA Group personal. Current document contains basic information about the system.

• boards pictures, general layout

• v1495-based logic: see GUI snapshots below

• Windows-based control GUI (see snapshot1, snapshot2 and snapshot3) were developed by Ben Raydo; it displays basic trigger logic and allows user to control and monitor various parts of the system using controlled logic elements, delays and lookup tables; built-in scalers are providing useful information about system functionality; system includes an multi-channel logic analyzer which was extremely useful to set appropriate delays (see snapshot1, snapshot2, snapshot3 and snapshot4)

• system incorporation into CLAS Online and Slow control: 9 OR modules were installed in sc2 crate, controlling script was provided to set appropriate masks into those units; v1495 was installed into clastrig2 trigger supervisor crate, and tcp server was developed and started under vxWorks to provide communication with Windows GUI and any other control and monitoring software running on UNIX machines; vxWorks timer-driven process is reading and reseting v1495 scalers every second placing data into semaphore-protected memory, so EPICS-related functions can extract necessary information from there; to provide EPICS support EPICS IOC was lunched along with CODA in clastrig2 crate, both systems are running together without problems; EPICS GUIs were developed (see snapshot1 and snapshot2) to display trigger system scalers; Windows-based GUI was installed on clonwin2 desktop which was accessed using remote desktop software from clon04 Linux machine