[Halld-tagger] [GlueX] EPICS events in data stream

[Alexander Somov]

Hello Richard,

Some beam quality variables should go to the data stream (also
some bpms readings). One can use these variables during data
reprocessing and raise a 'red flag' if smth looks wrong.

We have CTP scalers for PS which will provide us with the beam
energy (by the way, they can run even without daq).

Actually I would not put voltages to the data stream - we don't
want to add too much info to data.

Cheers,
       Sascha




On Wed, 25 Jun 2014, Richard Jones wrote:

> Sascha,
>
> Finding the coh peak position requires considerable analysis, and
> polarization fraction even more.  Are you sure you want to do this in
> EPICS?  This sounds more like an online monitoring job, writing to a
> database.
>
> -Richard J.
>
>
> On Wed, Jun 25, 2014 at 9:40 AM, Alexander Somov <somov at jlab.org> wrote:
>
>>
>> Hi,
>>
>>> From the Pair Spectrometer we'll record:
>> - PS coincidence rate for specific energy bin (lumi monitor)
>> - coh peak position
>> - polarization fraction
>>
>> Note, PS has a special trigger type, there will be a lot
>> of information available during data reprocessing.
>>
>> Cheers,
>>        Sasha
>>
>>
>> On Tue, 24 Jun 2014, Richard Jones wrote:
>>
>>> Hello David,
>>>
>>> For the microscope, I would like to have a set of key voltage levels and
>>> temperatures in the frontend recorded in the event stream.
>>>
>>> -Richard J.
>>>
>>>
>>> On Tue, Jun 24, 2014 at 7:52 AM, David Lawrence <davidl at jlab.org> wrote:
>>>
>>>> Hi All,
>>>>
>>>>  One of the features that will be implemented in the online is the
>> ability
>>>> to insert non-CODA events into the data stream. This would mainly
>> include
>>>> EPICS variables that might be useful in the offline analysis where the
>> full
>>>> EPICS archive is not readily available. For example, the electron beam
>>>> current or a temperature in the hall. What is needed is a list of the
>> EPICS
>>>> variables that might have value in the offline and the frequency by
>> which
>>>> to read and insert them. Realistically, variables cannot be inserted
>> more
>>>> often than once every 2 seconds. I assume many of these though will not
>> be
>>>> written more than once per minute. If you know of good candidates of
>>>> non-CODA data that should be inserted into the data stream, please send
>>>> them to me along with a suggested insertion frequency. I will compile
>> them
>>>> into a configuration file that will also serve as the official list.
>>>>
>>>> Regards,
>>>> -David
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>>>>
>>>
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>