Back Midas Rome Roody Rootana
  Midas DAQ System  Not logged in ELOG logo
Entry  13 Nov 2014, Tim Gorringe, Forum, using single frontend with multiple "EQ_POLLED" equipments to generate different data streams  
    Reply  13 Nov 2014, Pierre-Andre Amaudruz, Forum, using single frontend with multiple "EQ_POLLED" equipments to generate different data streams  
Message ID: 1039     Entry time: 13 Nov 2014     Reply to this: 1040
Author: Tim Gorringe 
Topic: Forum 
Subject: using single frontend with multiple "EQ_POLLED" equipments to generate different data streams  

We have a MIDAS frontend that provides both the readout of raw events 
and the processing of raw events into several distinct derived datasets. 
For one type of derived dataset there is a derived event for 
each raw event. For other types of derived datasets there's a
derived event for every N raw events. We'd like to have the different 
derived event types sent to different buffers / shared memory segments 
and stored in different midas files.

I was thinking of defining a separate equipment for each type of 
derived data. Each equipment would have a different buffer name so
the data would go to different buffers and thereafter to different 
midas files. I was also thinking of defining each equipment as
a "polled event" but with a unique "source ID". I believe the user 
poll_event() function is passed the "source ID" of the equipment
type and therefore could return success/fail based on whether or
not the particular derived event with that source ID is available 
for readout. Each equipment for each derived dataset would have 
a unique readout routine to create and fill the midas databanks 
for that derived event type.

The above scheme is similar to the midas documentation example
of a frontend with a trigger equipment and a scaler equipment
However, the scaler / trigger example uses two different event
types - EQ_POLLED for trigger and EQ_PERIODIC for scaler. I'd like
to use several EQ_POLLED equipments that are distinguished by
their source ID's

Is this a sensible scheme for make different data streams of
different derived event types from a single frontend? Has anyone
tried something similar? 
ELOG V3.1.4-2e1708b5