black stripes - bandwith problem - Vision Builder AI

[ThiCop]

Hello Tom,

Google helped me find some interesting things about some Manta HW.
The only thing I can't verify is if it's also applicable for your specific device (it's a generic manual I found).

- Jumbo frames/packets of the Network card should be 9014 bytes or higher.
- Receive Descriptors should be 512.
- ... (starts at page 27 of http://www.alliedvisiontec.com/fileadmin/content/PDF/Products/All_Manta_Hardware_Installation_Guide_...)

I also found something else somewhere else (again google 🙂 ) about your Network card.

This page (http://www.intel.com/support/network/sb/CS-001911.htm) notes that MACSec and jumbo frames are not compatible.
I assume that you're not "using" MACSec (http://en.wikipedia.org/wiki/IEEE_802.1AE), but I just wanted to provide you with this background info.

There also is a newer User Manual with some different requirements:
http://www.alliedvisiontec.com/uploads/media/AVT_GigE_Installation_Manual.pdf

[declercq_tom@waak.be]

Hi Thierry,

• Jumbo packets were enabled a few days ago (9014 bytes) but the problem remained.
• A few days ago I set the receive buffer to 2048 (highest option).
• A few days ago I set Interrupt Moderation Rate to extreme.

Because the problem still occured I enabled the Adaptive Inter-Frame Spacing, but this didn't see mto solve our problem.

Fot the moment Jumbo packets are disabled because we've did some tests with peciliar results:

• Pinging with jumbo packets enabled: Only works below 1500 bytes.
• Pinging with Jumbo packets disabeld: Works even with 9000 bytes.

Kind regards,

Tom

[ThiCop]

For some reason it seems to me that it might be related to the network.

Do you ever see this with one camera through the switch?

Or with one camera with a direct connection (no router) to your NIC?

Which kind of switch are you using?

[Goldy]

Dear sir,

What i think that this must not be a networking issue as what we had seen in trailing discussion that switch has much capability to support the details we need, it must be a program you need to verify the switching rate of cameras, you are working on MUX and DMUX system through switch and controling with Labview.

correct if am wrong..

Thanks,

[ZcuBa]

We experienced similar problems, but only when the camera was warm.
It was never hot beyond spec, but when getting close, we started loosing data and saw the black horizontal gaps in the images.

After having moved the camera to an area with better cooling, the problem have stopped occurring

I suspect the low level network interface in the camera (SVS Vistek) to be the cause.

I suggest you try measuring the temperature of the camera when the error is present, and when it is not, to exclude this thermal explanation.

[declercq_tom@waak.be]

Hi all,

I'm sorry that I kept you waiting. I was on a holiday and I made sure not to think of cameras 🙂

Now that I'm back it's time for an update:

* We've tested our camera's while warming them up well above the recommended temperature but we had no black stripes.

* A collegue experienced the same (black stripes) in NI MAX and in VBAI while streaming music simultaneous. He was only using one camera via a switch (same switch as mine). When he tries the same (streaming music) while using Halcon no black stripes appear.

* The only possible causes that I can think of are:

     * Interference of machines, engines... in the area.

     * Bad switch.

     * Network interference.

What we will test now:

* A different switch.

Kind regards,

Tom

[declercq_tom@waak.be]

Meanwhile we've been testing the difference between VBAI and Halcon:

* While streaming audio we get black stripes in VBAI.

* While streaming audio we never get black stripes in Halcon.

Could this be a driverproblem?

Kind regards,
Tom

[BlueCheese]

Can you switch to the High Performance network driver for your NIC?

Eric

[ThiCop]

Hello Tom,

I think it might be a good idea to restart with a more structured approach and try to eliminate as much causes in the fastest way.

Elimination questions:

1) Can you reproduce the issue with one camera directly connected to your PC (and also only one instance of VBAI)?

2) Can you reproduce the black stripes with one camera connected through the switch (and also only one instance of VBAI)?

3) How are you interfacing with VBAI?

Note: Please provide all settings you used for this acquisition as well as the VBAI files that were used.

Side Questions:

1) Are you using Halcon from the same PC as VBAI?

2) When talking about Halcon I assume you mean this.

Are you using the "standard" software or interfacing with it from another programming language (C# probably based on your programming language?)?

if yes, How are you interfacing with it?

3) If yes, are you using exactly the same network topology/connections?

4) Which settings have you defined in there?

[ZcuBa]

Hi Tom, 

now we know for sure that temperature is not the origin of your problem.

Then there are a few possibillities left.

I agree with ThiCop, you need to use a structured approach, for determining if this is a driver or network problem.

You still need to check if this can be an electrical noise problem.

The reason the temperature was an issue for us, was that the IC handling the Ethernet interface lost packets when it was hot. (don't ask me why, probably timing issues)

A damaged cable, or a cable that has been placed near electro magnetic noise sources (motors, welders etc.), can cause packet loss.

If the communication with the camera using VBAI doesn't handle this very well, the solution could be simply moving or replacing the cables.

So in addition to the Elimination Questions provided by ThiCop:

1) Can you reproduce the issue with one camera directly connected to your PC (and also only one instance of VBAI)?

1 a) if not reproduced, what if you use a long cable and place it near electrical motors or similar noise sources ?

2) Can you reproduce the black stripes with one camera connected through the switch (and also only one instance of VBAI)?

2 a) again try with cables near "noisy" equipment.

4) When using Haldon, does noise have any effects on the performance?

/ZcuBa