Re: [Daqpp-forum] scans

[Andrej S. <and...@ij...>]

Hi, Carlos!

How are you?

Came around to making a scan manager. Some questions:

- related to scan managers relation to data run manager: If the scan run
manager is defined as below, is it created only when Scan is pressed on
the VMEDAQ's front panel or is it the sole run manager and has to manage
normal data taking as well?

- is Trigger() routine called at the begining of each event? Can it be
understood as a StartOfEvent() pair to the EndOfEvent() routine? Should
module->Trigger() call Start()? If not, is module->Start() called before
or after Triggger()?

- does CheckEndOfRun() signal the DAQmanager to stop the run?

- I would make scan manager a child of Rmanager. Does that make sense? Am
I correct in assuming that all data loging will be then handled by
Rmanager and I should not bother by that? Would then the LogData button o=
n
VMEDAQ's front panel determine whether we log data or not? (ie. pressing
scan after log data would store events taken during the scan in data file=
s
as given by preferences dialog?)

There might be more questions. Thanks.

-Andrej


> Hello Andrej,
>
> Yes, you can certainly use the vmedaq scans for that. However, as usual=
,
> it will require some work on your side. The idea is that you create a
> new runmanager and load it with the configuration file (via one of thos=
e
> plugins) to be the one in charge of the scans. Say you create a run
> manager that lives in the shared library libMyRunManager.so. Then in th=
e
> config file, in the plugins section you write
>
> <plugins>
>    <plugin> ...whatever you might already have.. </plugin>
>
>    <!-- User defined run managers -->
>    <run_managers>
>       <scan>
>          <lib>path_to_the_lib/libMyRunManager.so</lib>
>          <hook>create_scan_run_manager</hook>
>       </scan>
>    </run_managers>
>
> </plugins>
>
> That means that in your library there should be a static "C" function
> called create_scan_run_manager (it can be any valid name for a function=
)
> that actually creates the run manager and returns a pointer to it.
>
> Now, user defined RunManagers are defined like user defined modules but
> are much easier, since you do not need to define GUIs, configurations
> nor anything like that. Take a look at the example in  making_a_module.
>
> To create your RunManager, I would propose to take ScanRunManager in th=
e
> daq folder and build from that. You will have to remove its
> "relationship" with PulseRunManager, since you do not need that, and an=
y
> call to methods to that class. Yes... I know that should be a "generic"
> class, and I promise I'll try to make it in the next release.
>
> How the thing works...   All the sugar is in ScanRunManager::Trigger.
> There it determines if we should start a new point in the scan or not
> and notifies to the modules. I guess that if you just need to move axes=
,
> the modules do not need to be notified, but who knows... This can be
> done in 2 ways, either change every N events or change every N seconds.
> Depending on the method, one uses an EventCtr instance or an EventTimer
> instance. This is done automatically, so I guess you only need to edit
> the files to remove the dependencies with PulseGenerator and, in
> Trigger, move your stuff whenever  (*next_point)() is true.
>
> Hope that helps.
>
> Regards,
>
> Carlos
>
> On Mon, 2007-02-19 at 11:54 -0500, Andrej Studen wrote:
>> Hi Carlos, everyone!
>>
>> I have a question. In what way is it possible to tamper with the scan
>> modality of VMEDAQ?
>>
>> Let me illustrate. What I have here is a scintillator camera which nee=
ds
>> to be recallibrated from time to time. To do that, we use a XY table a=
nd
>> record N=3D3000 events at a set of different positions (PMT centers,
>> orthogonal grids, etc.). I am tempted to use VMEdaq to do that. But my
>> user supplied scan routine should call external functions (move the
>> motor,
>> parse and analyze the data, move to next position) at each position. I
>> think it fits nicely into a scan philosophy. So, my question is: can I
>> do
>> that and if I can, what guidelines should I follow.
>>
>> A happy monday to everyone
>>
>> Andrej
>>
>>
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>  ___________________________________________________________________
>  Carlos  Lacasta
>  ^^^^^^^^^^^^^^^
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