Trigger for the FRS

Standard FRS trigger

Sorry, this page is still under construction !

At present, the standard FRS trigger consists of only one trigger (#1), which can be obtained from the logic operation of the standard detector signals.

They can be included simply turning on the corresponding switches of the FRS Trigger-Box 1 and 2.

The FRS Crate and any other VME crate included in the DAQ must be equipped with a GSI Trigger Module (Description as PDF-File) which controls the hardware readout timing cycle.

The GSI Trigger Module is programmable, for example, conversion time (CVT) can be programmed into it.

The FRS system works in a polling mode for triggering.

The FRS Trigger Module represents usually the Master Trigger Module.

Only it should receve the signal trigger provided by the trigger logic set up.

All the other trigger Modules, in case additional VME crates are present, have to be connected to the Master one via a bus cable.

In this way the correct syncronization of the hardware readout is guaranteed.

The trigger Module also provides some usefule output signals, including the accepted trigger (#1) and the total dead time (TDT) (#4).

When trigger input #1 occurs, the trigger Module check if the system is busy.

If it is not, the trigger word is sent to the processor and an accepted trigger is given as output.

If the system is already busy, processing a preavious event, the trigger is not accepted.

The TDT signal, present when the system is busy, can be used to gate other electronics.

 » FRS trigger logic scheme is here

Since August 2006, a VME Universal Logic Unit (vers.1), (VULOM1) has been added in the VME FRS crate.