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Sentech GigE Camera Loosing Data Packet

 

I am using two Sentech GigE (STC-GE500Acameras. For the most part the cameras runs fine but I am loosing a lot of data packets; my code is attached. Using information from this forum I have

1. Enable jumbo packets on network card

2. Change bandwidth

3. Change packet size

But none seems to eliminate packet loss. I get the same result even when I have the two camera on separate or on the same network card.

 

 

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Hi aderogba,

The lost of data packets may have been atributed by the timing delay that you have inserted in the acquisition loop as well as combination with not enough memory buffer to contain the amount of frame acquired within the delay time.

 

Try to lower down the timing delay that you put into the acquisition loop and may also want to increase the number of buffer allocated in the "NI IMAQdx Configure Acquisition".

 

Let me know the result of your experiment.

 

Regards

- Meadow -
LabVIEW 7.0 - 2011, Vision, RT, FPGA
TestStand 3.0 - 4.5
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Thanks for your response. I am still experimenting with changing the timing loop delay and number of buffer. One observation I have so far is that each time I try to increase the number of buffer above 21 I get "out of memory error". Do you know why?

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Hi Aderogba,

Your camera is 15fps with 5M pixel of either 8-12 bits data. This would easily translate to 10M per image size. The out of memory size may be because you don't have enough memory in the computer to create more than 21 image buffer.

 

Should you keep the number of buffer to 20 and lower down the timing loop delay, did you see any decrease in number of dropped images?

 

Regards

- Meadow -
LabVIEW 7.0 - 2011, Vision, RT, FPGA
TestStand 3.0 - 4.5
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The number of dropped images do descrease but didn't stop the problem altogether. Everything works fine for about 5-10min then the vi begins to drop images/packets.

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Hi aderogba,

 

Do you still loose packets if you only run one camera? I know you mentioned that you get the same result when you have the two cameras on separate or on the same network card, but I am not sure whether you are running them at the same time.  Additionally, have you tried to acquire images at a slower frame rate?  Does this still loose packets or increase the amount of time before you start loosing packets?  Another thing to check would be to lower the packet size within Measurement and Automation Explorer.  It is possible that you network card does not support sending such large packets.  Thanks!

 

Kim

Applications Engineer
National Instruments
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With one camera the image is fine, there is no packet loss even when I let the VI run for extended period of time. I have not systematically adjust the frame rate and packet. I will do this and send update about my findings. Do you gave recommendation for network card? Thanks.

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We don't have any official recommendations for network cards.  Really, just about any network card will work.  Let us know what you've found when modifying these settings.

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Hi Aderogba,

Glad to hear that the issue is getting better.

 

 

- Meadow -
LabVIEW 7.0 - 2011, Vision, RT, FPGA
TestStand 3.0 - 4.5
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