Experimental Physics and
Industrial Control System

Hi Katie,

 

Ø  This camera model should be capable of 8 kHz, but instead I get maybe half that frame rate with both the Basler Pylon software as well as the IOC.

Ø  We plan to update the network card to handle 10 Gb and I will let you know if that fixes this problem, since now this seems like a bandwidth issue.

 

You said the camera was 12288 x 1 pixels, running in 8-bit mode.  At 8 kHz that would be  12288*8000/1024/1024 = 93.75 MB/s.  That is close to the limit of GigE, but many GigE cameras can use that much bandwidth OK.  If you are only getting half of that then I would check for CPU utilization.  You can do that for the IOC with the “top –H” command.  That will show you the CPU utilization of every thread in the areaDetector IOC.  If any thread is close to 100% then that could be limiting you.  I would be surprised if using a 10 Gbit card would help, because the network interface on the camera is only 1 Gbit, right?

 

Ø  My only other question comes from grabbing my BASLER1:image1:ArrayData PV;

Ø  I have my EPICS_CA_MAX_ARRAY_BYTES set to 150,000,000 (very large for testing) on both the host as well as inside the IOC (verified with epicsEnvShow).

Ø  When I caget BASLER1:image1:ArrayData, it outputs the following error,

Ø  "BASLER1:image1:ArrayData *** CA error The requested data transfer is greater than available memory or EPICS_CA_MAX_ARRAY_BYTES".

Ø  I can return the array using caget up to  ~8100 elements, after which I receive the above error.

 

When you say “8100 elements” how big is each element, i.e. what is the FTVL of your waveform record?

 

First, I would decrease EPICS_CA_MAX_ARRAY_BYTES to a value like 20,000,000.  My understanding is that the IOC and the client will actually allocate arrays of EPICS_CA_MAX_ARRAY_BYTES if an array larger than the default size is needed, so it will be using a lot of memory unnecessarily. 

 

Please send the output of this command in the IOC

epicsPrtEnvParams

 

and this command at the shell running caget

echo $EPICS_CA_MAX_ARRAY_BYTES

 

Something is wrong if you are getting that message.

 

Mark

 

 

 

 

From: Katie Matusik <kmatusik at sigray.com>
Sent: Thursday, April 8, 2021 5:24 PM
To: Mark Rivers <rivers at cars.uchicago.edu>
Cc: EPICS Tech-Talk <tech-talk at aps.anl.gov>
Subject: Re: line scan camera with ADAravis driver skips frames

 

 

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