[Dsg-hallb_magnets] Torus Fast-DAQ time gap debug

[Nathan Baltzell]

Hi Tyler,

These fixed 200 ms gaps are likely from missed PV updates between the cRio IOC and the softIOC (update rate of 5 Hz --> 200 ms) and not due to incorrect time stamps.

We first saw this issue when the PV update rate was increase from 1 Hz to 5 Hz, and, if I remember correctly, Christiana found it to be related to heavy cpu load on the cRio and found some way to resolve it.

-Nathan


On Jan 30, 2017, at 4:13 PM, Tyler Lemon <tlemon at jlab.org> wrote:

> Hello Nathan, Nick, and Wesley,
> 
> This afternoon, I tested a few different configurations of the timing loop on the Fast-DAQ cRIO that I thought would fix the 200ms time gap we are seeing. The 200ms time gap still appeared for all tests.
> 
> Also, I made a subVI that uses the local variables that make up the EPICS IOC to display the Fast-DAQ data arrays. I cannot see any time gaps in the data using LabVIEW.
> 
> This leads me to think that there is something happening on the EPICS end (whether EPICS server on cRIO or elsewhere) where incorrect time stamps are assigned. I can see in the LabVIEW that there is nothing that assigns a time stamp to data passed to EPICS. Maybe adding any sort of time stamp or counter would allow the data to be stitched together correctly. The new time stamp could be added as an additional PV sent to EPICS.
> 
> Best regards,
> Tyler
> 
> From: "Ruben Fair" <rfair at jlab.org>
> To: "Tyler Lemon" <tlemon at jlab.org>
> Cc: "dsg-hallb magnets" <dsg-hallb_magnets at jlab.org>, "Dave Kashy" <kashy at jlab.org>
> Sent: Monday, January 30, 2017 1:41:07 PM
> Subject: Re: [Dsg-hallb_magnets] Torus Fast-DAQ time gap debug
> 
> Hi Tyler,
> 
> There will be no energization of the Torus today.
> 
> Regards
> 
> Ruben
> 
> From: "Tyler Lemon" <tlemon at jlab.org>
> To: "dsg-hallb magnets" <dsg-hallb_magnets at jlab.org>
> Sent: Monday, January 30, 2017 1:38:52 PM
> Subject: [Dsg-hallb_magnets] Torus Fast-DAQ time gap debug
> 
> Hello,
> 
> Since the Torus is not presently powered, I am going to try to implement a possible solution to the 200ms EPICS time gaps. I will record data with the EPICS data logger before and after to see if the change stops the 200ms time gaps. 
> 
> The change will momentarily stop the Fast-DAQ cRIO and trip the "cRIO Fast-DAQ Comm" interlock. The interlock will be able to be reset after the program is deployed.
> 
> Please let me know if any upcoming tests are planned that will require the Torus to be energized since Fast-DAQ cRIO communication loss will cause a controlled ramp downs. 
> 
> Best regards,
> Tyler
> 
> _______________________________________________
> Dsg-hallb_magnets mailing list
> Dsg-hallb_magnets at jlab.org
> https://mailman.jlab.org/mailman/listinfo/dsg-hallb_magnets
>