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FIFO errors with 1433 and IMAQ 18

IMAQ-18 – running on a Win 7 workstation with a PCIe-1433 card connected to our high speed medium Camera Link camera (running at 147,000 lps).  This 2048 pixel line camera uses an 80 MHz strobe and transfers 4 pixels per clock.

The installation has been used intermittently this year without a problem.  Last week I found with our LabView executable program that I was getting video timeouts and/or FIFO errors within a minute of starting a GRAB.  I then switched to MAX and found that the acquisition line rate was being limited to ~100 k lines per second (no errors, just limited rate). If I slowed the camera from 147 k lps to below the 100 k rate, the MAX display would follow.


The PC involved processed a corporate and Windows security update prior to these symptoms.  Can you help me identify the issue and hopefully restore full bandwidth support?


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Message 1 of 11

How many lines per image are you acquiring?

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Message 2 of 11

In this case 1000 lines per image, so I should see MAX report 147 fps if it was acquiring lines at the camera output rate of 147,000 per second.  Instead, MAX reported ~100 fps.

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Note that under IMAQ 17.0 on a different PC but otherwise the same configuration, no FIFO errors with our LV program, and MAX acquires at the full camera rate.

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Generally, any performance issues would be expected to be related to your frame rate, since that is how the board is actually processing the data and interacting with the software driver. 147fps sounds very low such that there should not be much that would prevent the driver from keeping up.


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Message 5 of 11

When you write that you camera is getting 80MHz strobe I would assume it is to sync with a moving object.

When you are syncing with moving object. Are there cases that the strobe rate goes above 85MHz? 


Amit Shachaf
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Message 6 of 11

Amit:  This is a camera-link line-scan camera - the camera drives the CL clock at 80 MHz, which is safely below the standard's limit of 85 MHz.  These cameras have been in production since 2013 and the same specific PCIe-1433 card in the same PC has supported the camera's full 147,000 lps rate until this situation started under IMAQ 18.  Now in LV I get FIFO errors and under MAX the acquisition is capped at 100,000 lps.  This limit is constant whether I capture 100 lines per image (should produce 1470 fps but I only see 1000 fps) or an image height of 1000 lines (should produce 147 fps but MAX limits at 100 fps).

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Message 7 of 11

If you reduce the width of the line captured do you see any change in the max rate or is it purely related to maximum line rate?

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I am not sure that I know how to help. Only information I can give you that I am qualifying to our system a new camera JAI GO-5000.

I was testing the configuration with NI PCIe-1433 LabVIEW 2018 on Win 10 64bit. My final  implementation will be on NI PCIe-1477.

I am configuring the camera to 2048x100 image size and acquisition is full camera link. I am able to get >1000 FPS with NI example programs. 

It might be that I am running with camera link full. But I am getting much higher data rate then yours without issues on the 1433.


Amit Shachaf
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Message 9 of 11

BlueCheese:  Yes, if I reduce the line width in MAX, the line rate comes up proportionally.  A line width of 1350 pixels seems to reach the 147 fps with 1000 line image.  1350x1000 is 1.35 Mpixels per frame, 2.7 MBytes per image, X 147 fps gives about 400 MB/s.  2048x1000x100x2 is about 409 MB/s. so that seems to be the new bandwidth limit.  I need over 600 MB/s. I'm running medium Camera Link, with 4 x 12-bit pixels per CL clock cycle. (PC transfers 16-bit words so that is why I use 2 bytes per pixel for the bandwidth estimate.)


Amit:  Your example appears to be 2048x100 lines x 1000 fps x 2 bytes, also about 409 MB/s.  Can you increase your image height or run the camera faster than 1000 fps?

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Message 10 of 11