USB 6008 card disconnects frequently

[SANKAR_meil]

I m using NI 6008 Multifunction DAQ card, I m controlling the 3 phase motor and its direction using this card thro relays.

And measuring 4 channel analog inputs. While running application, USB 6008 card loses communication with the Computer, and i need to unplug, then plug the card. Its happening frequently. So, how i can avoid this ?? is ther any solution to this??

Thanks & Regrds,

sankar.s

[Tom__Sedlack]

You may be having noise issues from the relays and motor that are causing the 6008 to get "confused".  I would suggest using opto-isolators to drive the relays (that drive the motor).  Adding a snap on ferrite on the USB cable going to the the 6008 sometimes helps.  Also, watch you cable routing.  Don't bundle the USB cable with the relay/motor control cables.

[SANKAR_meil]

hi,

Thanks for the Reply, I m using Opto drive Relays and snaps at both ends of USB cable.

Few days it was fine, and again started to break communication regularly.

So, i dont know how to solve ?? Sud i replace this card with PCI card ???

Thanks & Regards,

sankar.s

[Shreyas]

Does the communication break even when in normal operation?

What is the error code that you are recieveing?

[SANKAR_meil]

Here Communication breaks means, the card stops responding, and the system getting hanged.

After unplug then plugging starts communication till it breaks again.

we using around 5 to 6 USB 6008 cards, especially in 2 machines, where we control clutches and 3 phase motors using this USB 6008 card breaks communication with PC frequently.

I had tried using snaps in all the machines !!  

Other machines deals with only Analog inputs, so the problem is not frequent. But it occurs on those machines too.

What could be the reason ?? Any solutions to solve this ??

Sankar.s

[SANKAR_meil]

No Error i m getting, just all Analog inputs reads Zero, then Hanging few secs.

Its breaks even when machine not in operation!!

Thanks & Regards

sankar.s

[JÞB]

see This post

for some potential explainations from my experience

[SANKAR_meil]

Thanks jeff.

Let me try with the External powered USB hub.

Will come back to u.

Thanks Again.

sankar.s