View Full Version : Using two DFK 72AUC02-F at the same time

August 19, 2014, 09:27:42
I'm trying to use two DFK 72AUC02-F cameras at the same time. However, in IC Capture 2.3, when I select the maximum resolution of 2592x1944 for both cameras, I'm getting a timeout with one of the cameras. Apparently it can't handle the load. I have lowered the frame-rate to the lowest possible value of 1.71 fps and it still doesn't work.

Once I reduce the resolution to 2048x1536 it works.

To rule out some obvious potential issues, here is some extra information:
- Host: Intel i7 @ (2.10 GHz 2.10 GHz)
- I tried procidlestateman_2.2.0.2.exe, not change
- I used two dedicated USB 3.0 ports on my PC.
- TIS USB Drivers (Version appear to be installed and working fine

USB 2.0 has a maximum bandwidth of 480 MBit/s so it should be able to handle 2x5MB/s. So what could be wrong? What else can I try?

Thanks in advance!

Stefan Geissler
August 19, 2014, 10:14:26
Hello Marius

please take care of the USB bandwidth, if both cameras are connected to the same USB controller. In IC Capture, set the frame rates of both cameras to 2 - 3 fps, if they should run in full resolution. The frame rate is set in an an "fps" labeled combo box on the right side of the device tool bar.

August 19, 2014, 10:18:17
As I said, the FPS is already set to the minimum (1.71) and the cameras are connected to 2 individual USB 3.0 ports (the only ones on this system). I'm using no hub. The bandwidth should be sufficient.

Stefan Geissler
August 19, 2014, 10:25:36
1.71 fps is fine. The USB controller turns down to USB 2.0 speed, if a USB 2.0 device is connected. However, you may try Processor Idle State Manager from http://www.theimagingsource.com/en_US/support/downloads/details/procidlestateman/
I suppose, somehow some data blocks are not picked up by the USB controller. This should not happen with USB 3.0 PCIe controllers, but I am not sure about this.

August 19, 2014, 10:57:50

as stated in the initial post I have already tried the Processor Idle State Manager.

What I haven't mentioned yet is that I'm on Windows 7, in case that is relevant in any way.

Other than the cameras there is no stress on the USB sub system whatsoever. I'm really running out of options. All in all this is quite disappointing. We have already ordered a number of cameras and were definitely not expecting this kind of setback. Is there anything else I can try?

Stefan Geissler
August 19, 2014, 16:12:29
Each camera runs fine alone?

Test driver 2.7.9?

Which computel model (Model name, manufacturer) is in use?

August 20, 2014, 08:14:45
I'm on a Lenovo T431s Notebook. Yes, each camera runs fine alone. I found out more: normally the cameras appear beneath the Intel eXtensible Host Controller Node in the USB device tree. When I switch off USB 3.0 support in the BIOS, this node disappears and the cameras appear beneath the Intel(R) 7 Series/C216 Chipset Family USB Enhanced Host Controller - and then it works. But obviously I loose USB 3.0 functionality which isn't great. Do you have any idea what could be wrong here?

Stefan Geissler
August 20, 2014, 08:58:36
I must admit, I have no idea, what is wrong there. I only know, the USB 3.0 chipsets and their drivers are still in development...

However, I note this. I will do a similar test on my computer, but I have an older TI USB 3.0 PCIe board only.

Stefan Geissler
August 20, 2014, 09:23:35

I tested on my own, using a Texas Instruments USB 3.0 PCIe controller. I confirm, you can not run two DFK 72 on USB 3.0 with maximum resolution. The reason is, that the controller does not pick up all data blocks in time, so the cameras detect a buffer overrun, notify the driver and the driver drops the frame. If I disable the frame drop in my dev-driver, I see the damaged images.

I have to admit, I have no idea, why USB 3.0 controllers behave in this way.

After this test, I connected both cameras to an USB 2.0 controller. No problem running both cameras with 3 frames per second in full resolution.

August 20, 2014, 11:43:26
Thanks for testing this on your end. Please let me know if you gain further insight. I'm sure you'll also pass this on to the developers - USB 3.0 only machines will soon be the common case.