OC relay card suddenly behaves strange.

[crashdog]

I can't understand what happend at the moment. I have connected 2 relay cards. Both behave strange.
I have a overhead panel with bulbs in it. I use the OC relay card to enlight the bulbs according to the overhead panel software. This worked for many months without troubles. Until yesterday. Now I can only switch on one Relay. (Means the test LED lamp goes on). If I switch on any second relay, it will shortly switch on but then both test LED's go off and no bulbs light up. Seames that it's switching both relay's to the off position again even if they should be on.

It's probably nothing wrong with the relay card. I took a new unused relay card out of the drawer and connected it instead of the one connected to the OH bulbs. With the same result. Even if nothing is connected to the relays.

The only thing I know I fiddles with are the USB hubs where the OC cards are connected. But the OC io_card_test.exe recogizes both cards connected and the ports in sioc.ini looks correct.

Has anyone had a simmilar problem before ? any solution suggestions ?

I added a video to demonstrate what I mean:

[crashdog]

I excanged one usb cable... and now it works again... even stranger...
Is it possible that OC cards are not USB 2 compatible ? I think I have one USB hub which is USB v1.0 and one USB hub that is v2.0.
Any way it works again !