What does discover cameras actually do?

[Andrew_Scott_SPCi.ca]

I am unclear what the Discover Ethernet Cameras VI does. The problem I am trying to solve is that after a cold power up we sometimes get an error the first time we try and open a camera. Exiting and restarting the application fixes the problem. We never see a second error while running. We only see errors after a reboot. The error is usually Camera Not Found. All the cameras are on the same PC on different static IP addresses. We are running LabView 2009 and VAS 2010

I think the Discover Ethernet Cameras VI should fix my problem if called before the first camera access, but it does not seem to... Here are my questions?

1) Does a single call to the VI find all cameras or do I have to call it once per IP address?

2) If I call the VI with a specific IP address where there is NO CAMERA, it does not return an error. Why not?

3) When I get the error on a cold boot, I sometimes also get a timeout on the discover cameras VI. Why?

Thanks. The documentation is a bit vague as to what actually happens when you call this VI.

Andrew

[Greg-H]

Hi,

This VI is used to find any cameras that are on the network, if you already know the IP addresses of the cameras then this VI is not really necessary since you know what cameras are there.  What does the actual error you are getting say?How long after the boot are you waiting to run your program?

Regards,

Greg H.

[Andrew_Scott_SPCi.ca]

Hello Greg.

Here is what happens. I start the acquisition VI via the VI Server. This VI Configures the cameras (two or three) but does not start acquisition. It is done this way because the configure is quite slow (7 seconds) due to the flat field load. The configuration happens with a few seconds of boot.

When I go to start the cameras later (can be many minutes after the configuration), the error I receive is "failed to receive test packet from camera".

If I just reboot the PC without powering down, then it works fine all the time. The error happens only the first time after a power up. I have tried a delay at the start before configuring the cameras but it does not help. It does not happen every time on customer PC's (about one of two times), and of course, never happens on my development system.

Using the Discover Etehernet Cameras VI changes the nature of the error (I used to get a "camera not found" error before I added the Discover Ethernet Cameras VI).

It is just one of those annoying issues that I would like to fix.

Andrew

[Greg-H]

Andrew,

What kind of cameras are you using?  When you say power up are you refering to the actual power to the computer or just the power to the cameras?

Regards,

Greg H.

[Andrew_Scott_SPCi.ca]

Hello Greg,

We use Dasla Genie cameras. We have the same problem with different cameras (640 by 480, 1280 by 1024). It does seem to be the color cameras which give the problem. Perhaps something to do with the 7 seconds required to load the flat field correction.

I have done two different experiments. If you power the PC only, there is no issue. If you power down everything including the cameras, then you get the error message.

Andrew

[Greg-H]

Andrew,

When you ge the error what is the exact work around to correct the problem?  It sounds like either the camera does not have enough time to boot up and make itself available to the computer or it is not receiving a necessary initial command.

Regards,

Greg H.

[Andrew_Scott_SPCi.ca]

Hello Greg,

It does matter how long you wait or whether the EXe is in the startup or not. It seems to be something about the first access. I will be going to a site next week, and if it happens there, I will have a better chance of getting to the bottom of it and will report back.

Andrew

[Greg-H]

Andrew,

Sounds good.  The .exe you are talking about, is it the applicaiton you wrote or the manufacturer's?

Regards,

Greg H.

[Andrew_Scott_SPCi.ca]

It is ours. A very complex imaging app that measures and reject individual objects from a random flow spread across a 40" wide belt at rate of 30 per second.

Andrew