Hi there! We are working on an AI system and using 4 ZED2i cameras. Usually everything works well, but sometimes we have troubles with one camera (camera turns off, python sdk doesn’t see it, ZED_Explorer says “connect to another usb port”). If you replug all cameras to the same usb’s - everything works again for a while.
We suspect that our weak motherboard is to blame (it didn’t even have usb 3.0 ports and we added them). This is our hardware:
This is a USB bandwidth issue. The ZED2 requires the full bandwidth of 1 USB 3.0 controller when using the full framerate (let’s say HD720@60), so you’ll need 4 separate USB controllers for 4 cameras at full framerate or half that for half the framerate…
I would recommend adding a USB PCI Expansion card. Since this configuration is quite old I think half framerate is acceptable (like HD720@30) so you would need at least 2 PCIe expansion cards if there’s 1 controller per card. Although 4 ZED SDK instances will need quite a lot of computing power to run, depending on the parameters used.
Thanks for quick response!
I would like to clarify what we are already using PCIe expansion card (this one).
And since we most often need just pictures, we use either HD720@15 or HD1080@15
So, should we use more than one PCIe expansion card?
This PCIe expansion card has 1 USB controller, so in theory, HD720@15 should work for 4 cameras. We recommend not starting them all at the same time though, adding a few seconds of delay may reduce detection issues.
However, HD1080@15 is twice the bandwidth of 720@15. So yes, I would recommend adding another PCIe expansion card similar to this one and it should work (with 2 cameras per expansion card). You should also make sure to power the PCIe card as this can also cause issues (through the SATA 15-pin connector on the PCB)