When adding a second firewire hub, why do some camera's I plug into the 2nd hub not show up in MAX

[DelphiDan]

Hello,

My application requires 8 firewire cameras.  I have 2 PCI slots available on my PCI.

I'm using a (1) 2 port fire-wire PCI card, with each port going to a 6-port belkin firewire hub.  I have 4 AVT Guppy cameras plugged into 1 Hub.  I have had no problems until I hooked up the 2nd firewire hub to the 2nd port of the fire-wire PCI card.  When I plugged 4 more cameras into the 2nd hub and added the cameras to devices in MAX as Legacy drivers, weird things started to occur.  First of all, normally the cameras are added pretty quick, but when I got to the 6th camera it started to take a longer amount of time to add the driver as a Legacy camera.  Secondly, one camera in the 2nd hub was reassigned a camera number from the 1st hub and vice-versa.  Thirdly, when I exit MAX and go back into MAX some camera's I once added are now missing.   If I exit MAX and go back into MAX again, some cameras show up but others are missing.   I got all 8 camera to show up initially, but now I can't see 8 cameras.  I even have had a "internal error" show up when clicking on a camera in MAX. 

Can someone explain what is going on?   Do you think this is a hardware constraint with the PCI firewire card?   Or a constraint with NI's software because of addressing confusion when using 2-hubs off 1 card?

What is your recommendation for hooking up 8 firewire cameras, but only have 2 PCI slots available in my PC.  

thanks

[BullDozier]

Hey Delphi Dan,

So if I understand correctly, your problem is that you have 8 firewire cameras plugged into the same PCI Firewire card through 2 Hubs and you are having problems with them all showing up in Measurement & Automation Explorer.

The first thing that comes to mind is that unless the hubs are self powered, all 8 of the cameras have to get their power from the PCI Firewire card.  This may cause the cameras to fight for power, which would cause some not to show up at random in Measurement & Automation Explorer.

The 2nd idea that I have is that your 2 port Firewire card probably only has 1 Firewire bus chip on it.  This means that anything plugged up to that card has to share the total bandwidth of the firewire bus, which is 400 Mb/s.  That means that all 8 cameras have to share this bandwidth and they may be overloading the bus if they are all trying to work simulatneously.

What I suggest is to place a 2nd PCI Firewire card in your computer and plug half of the cameras up to the new card and half of the cameras up to the card you currently have.  This will allow the cameras to have more power and more bandwidth to share.

I hope this helps out, but if it doesn't, post another reply and I will be happy to help you further.  I look forward to hearing from you.

[DelphiDan]

I checked the firewire board and it is a single bus with 2 firewire ports.   I think you're idea of a 2nd firewire board and splitting the 8 cameras between the 2 boards is a good idea.  I'm also gonna look into finding a 1 firewire board with dual buses.  The machine has already shipped to Mexico in this state.  I will be going down there next week to debug further.  Do you anticipate any problems with cameras being assigned wrong after routing the other 4 cameras to another firewire board after already plugging them in the first board?   Should I start over and delete all the files out of  NIimaq1394/data/ and clear the registry key for enum/1394/ Guppy/ so I can have MAX reconfigure the drivers.   I have done this in the past with luck, but want to minimize any risk factors.

Thanks

[BullDozier]

Hey Dan,

I am unsure if finding a board with two buses will completely eliminate the problem.  I am worried that, even with two discrete buses, the PCI card may be pulling as much as a single PCI card can pull.  Maybe if you could find a single board with an option for external power from the computer's power supply (like most AGP video cards) so that the PCI bus wouldn't have to supply all of the power.  I think that the best method would be to find a second board so that you could use two separate boards.

I also do not think you will need to delete the camera files from the data directory.  They should be picked up and authenticated in Measurement & Automation Explorer just fine.  Let me know if you have any issues with this and I will help you troubleshoot.

I hope this turns out ok for you.  Let me know how it goes!