[Halld-level1] Data stream scalers, summary of the meeting

[Alexander Somov]

Hi,

The server runnning on the ROC might not be just an EPICS IOC,
but more complicated. It should handle messages/requests
from other debugging programs and provide an arbitrage for
accessing registers. For the trigger debugging I would not rely
on EPICS but just use 'standalone' debugging tools.

At high rate we have to be sure that EPICS doesn't interfere with
the CODA readout (it should not, but has to be checked). Anyway,
the data stream scalers themself should provide a reasonable
online dq/monitoring tool.

Cheers,
       Sascha



Hi Dave,
There will be scalers that will be available for monitoring
programs. These registers will be written and readout independent
of CODA DAQ. This info is going to be available in EPICS for general
purpose monitoring.
Whenever there is a need, we will have EPICS IOC running on the VXS
crates CPU.
At least that is the plan.
Hovanes.

On 01/23/2012 01:32 PM, David Lawrence wrote:
> Hi Sasha,
>
>     Are they counting even when the DAQ system is not currently taking
> data? I would think we would want an out-of-band way of getting at the
> scalers. That way, we can display them at any time (e.g. while tuning
> the beam in between runs). Maybe you mentioned something about this
> before...?
>
> -Dave
>
> On 1/23/12 1:25 PM, Alexander Somov wrote:
>> Hi Elton,
>>
>> A good point.
>>
>> You don't need to disentangle the whole events.
>> Scalers will have a tag in the fadc event block;
>> one will need to search for the corresponding tags
>> only; should be straight forward.
>>
>> Cheers,
>>           Sasha
>>
>>
>>
>> On Mon, 23 Jan 2012, Elton Smith wrote:
>>
>>> Hi Sasha,
>>>
>>> Thanks for the summary. In mode a) can easily scan through a file and
>>> pick out the events with scalers (without disentangling the whole 
event)?
>>>
>>> Elton Smith
>>> Jefferson Lab MS 12H5
>>> 12000 Jefferson Ave
>>> Suite #16
>>> Newport News, VA 23606
>>> (757) 269-7625
>>> (757) 269-6331 fax
>>>
>>>
>>> On 1/23/12 9:10 AM, Alexander Somov wrote:
>>>> Hi,
>>>>
>>>> I brief summary of the data stream scaler
>>>> implementation  discussion last Friday
>>>> (Jan 20th, 2012):
>>>>
>>>> 1. Scalers will be integrated into the data readout
>>>> block of each FADC; they will be readout using DMA.
>>>>
>>>> 2. There are two ways of the implementation:
>>>>       a) scalers will be added to the last event in
>>>>          the block. A user needs to specify the block
>>>>          prescaling factor, i.e., the number of blocks
>>>>          after which the scalers should be added
>>>>          (for instance, add scalers in each 10000's readout
>>>>          blocks).
>>>>       b) Scaler readout will be handled by the special
>>>>          trigger type generated by the TS (the trig2 line
>>>>          going from the TI to the fadc can, for instance, be
>>>>          used for the scaler trigger distribution). Similar
>>>>          to a), scalers will be added to the readout block.
>>>>          Implementing this mode will require more efforts.
>>>>
>>>> 3. Edd and Bryan will start implementing mode a).
>>>>
>>>>
>>>> Cheers,
>>>>           Alex
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