PXIe-8135 controller USB port issue

[jharris66]

Hi,

We have been exhibiting some strange problems with a PS2 keyboard that we have connected to a USB port on PXIe-8135 via PS/2 to USB adapter.   Every now and then the keyboard does not enumerate properly and the lights on keyboard are very dim.   We seem to have a workaround of putting adapter in other port when we get into this state.

We have used this keyboard model with other PXIe-8135 controllers in the past with no issues. 

The keyboard specs indicates it draws ~ 35mA, although I am unsure about any surge currents when it wakes.

Could this point to a PXIe-8135 USB issue?    We have no issues with other USB device on the controller (a USB mouse).

Thank you

[FmTesla]

Hello jharris66.

Is this problem something recent? Has this model worked properly in the past with this PXI-8135? Have you tried to use it with the other PXIe-8135 recently? Is it only presenting this behaviour in one specific port? Which ports have you tried? I just want to discard the possibility of the equipment being damaged or something being configured incorrectly and alienate the issue to the main cause. 

[jharris66]

It seems to have been present since we received the PXI controller.   The scenario where we run into the most problems is upon PXI reboot.   We have used the same keyboard model with two other test racks with a 8135 controller.

We have tried different ports and see the same issue.

We are hoping a powered-up or other PS/2 to USB adapter might workaround the issue since replacing the controller at this point would be costly from our project standpoint.

[FmTesla]

Ok, but when you say "the same keyboard model", you mean the same keyboard, or another keyboard that is just like the one that is giving you problems? Have you tried that keyboard specific unit on another PXI? I just want to discard the possibility that the problem is with malfunctioning of the keyboard and not with the controller. 

[jharris66]

Another keyboard that is just like the one giving us problems.

We don't have another PXI controller to try a test.

I have tried it on my desktop PC with no apparent problems like what was seen on PXI controller.  I'm wondering if the PXI controller USB ports are not sourcing enough current during the enumeration phase or if there is a device management issue with Windows 7.  

[FmTesla]

And have you tried with another similar device (keyboard), but USB, without the adapter? Does this particular unit (keyboard) works correctly on a regular computer?

What really seems bizarre is that it is working some of the time. The most common problem is keyboards not being recognized, but not working only half way.