Scalers
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[edit] CAVEAT
This part of the acquisition is in a state of high flux and likely changes experiment to experiment (if not day to day). If there is something that you can't reconcile with this web page, check the e-log for hints like this entry for E1069 here. You might end up having to track down cables and ODB entries yourself.
[edit] What are they
Scalers are provided for counting things like trigger or pretrigger rates, or counts from auxilliary detectors (like a zero-degree low-rate beam counter). The scalers are five (5) SIS3820 MCSs from Struck Innovation. All five take two 34-pin ribbon cable connectors. They are configured to be read out and cleared as MIDAS periodic events; as of writing, this is done every second, and at the very end of a run. (See CAVEAT)
[edit] MIDAS Front-End Client
The scalers are defined in the TIGRESS MIDAS DAQ system as MCS. They are read out by an independent front-end client program. If the MCS cell on the main DAQ status page is red, then this front-end program has crashed. See the Starting and Stopping the MIDAS Clients pages for information on how to start or restart it.
[edit] Online access
To view the most recently read contents of the scalers, simply look in the /Equipment/MCS/Variables ODB entries. These can also be viewed by clicking the MCS link on the status page.
[edit] Offline access
Each time the scalers are read out, the contents are logged, just like regular physics events. They have Event ID 3. The MCS1 and MCS2 banks are included in these events. They can be accessed either through mdump -x oldrun.mid -i 3 or by your own favourite offline analyzer.
[edit] Coupling to EPICS
See the new Epics Front-End page for details of how to configure things. Also, see the EPICS info on the 8pi page for a more evolved (although not entirely applicable) introduction.
[edit] Gotchas
[edit] Technical Details
In progress.
