PDA

View Full Version : Problems with more than four cameras in chain?!



Sascha.E
April 16, 2007, 11:17:04
Hi,

i am currently working on a programm to get 9 cameras in a row with live frame and the option of taking frames from them. Therefore i am using cameras of the DMK 21F04 Series and Borland Delphi 5.
But there occurs a problem all the time. I cannot use more than four cameras simultaneous. If i activated four of them everything is allright but if i call the LiveStart procedure the programm crashes with an error in the ".\GrabberPImpl.ccp" at line 580.

I already contacted one of your supporters via telephone and he advised me too reduce the frame rate and i should be able to operate
3 cameras @ 30fps
5 cameras @ 15fps
10 cameras @7.5fps
but this does not work.
Am I doing wrong or what is the problem? Do you have any ideas?

Regards, Sascha

Johannes Vogel
April 16, 2007, 13:19:18
Hello,

which version of IC Imaging Control are you using?

Sascha.E
April 16, 2007, 14:11:18
I am using Imaging Control 3.0 active x plugin ...

May it be that my 1394 Controller is not able to make enough bandwith available to support more than four cameras of that type?
IC Capture return an error value that talks about that possibility.

Johannes Vogel
April 17, 2007, 09:29:33
Hello,
there might be a bandwidth problem because it is not gurarteed that you can use twicw as much cameras simultaneously if you decrease the fps by a factor of 2 because there is a certain data overhead. The overhead is caused mainly be the fact that data is sent in packets of a fixed size.

Another possible reason for problems is power )or lack os power). Maybe your FireWire port doese not provide anough milli amps. especially PCI boards that are powered over the PCI connector may suffer from this problem.

Did you try to use more FireWire controllers?
Using externally powered hubs may help.

Sascha.E
April 17, 2007, 19:11:52
Hello Johannes!
Thanks for your reply. I have been to your office in Bremen today to get myself two similar firewire cards of the type u use them yourself.
After that I changed the computer to work on. The changes are:
- Upgrade from windows 2000 to windows XP
- Two instead of one firewire card
- The computer is able to handle a 11Mpxs Camera from SVS Vistek (so it is not the weakest one)

After that I experienced another big problem:
- The Computer recognizes all six cameras I have
- Imaging Control (Active X in the same way as the Sample Programs and IC Capture) is not able to adress more than three of the six cameras. In this case the computer seems to choose the cameras I can adress in a random way. It is other cameras on every try.

The Windows 2000 computer didn't take any changes in handling the cameras after upgrading to two 1394 controllers.

To the Power Problems suspect:
- I tried two different PCI Powering Controller simultaneously - it was the same effect as it was before: either the program crashes on the fifth camera (Windows 2000) or I cannot adress more than three of six cameras (Windows XP)
- I tried to use a firewire controller card taking the power to provide the 1394 devices from the Power Supply of the computer itself. I got the same effect as i got in the configuration above.

I don't have any ideas anymore what is going wrong with that cameras or computers. I hope u got something left to help me out of that blind alley.

I will suggest that external powered hub solution to my boss.

Regards Sascha, Uni Bremen

Stefan Geissler
April 18, 2007, 08:39:51
Sascha,

each camera needs app. 200 mA. 1.5 A is specified by IEEE 1394, but this does not mean, that any computer will be able to deliver as much as needed power. Thus an external power supply is a good idea. (I suppose I discussed this already with you boss.)
If the problem consist, please contact me by phone, thus I can have a look on your hardware in Bremen.

Sascha.E
April 18, 2007, 08:52:24
I will do so :)

thanks for your active help in here. We will try that and report back to you if we got any results.

Regards, Sascha