Dynamic Signal Acquisition

[maggotsBrain]

Hi,

I need to install a NI X-Series 6361 USB and I would like to know if this device does require an external power alimentation, because it is mentionned in the DAQmx manual that it depends on the device used but I can't find that piece of info anywhere in my case.

[gaving]

The USB 6361 comes with an external power supply which is how you power the device.  Is that what you mean?

forgive me, I'm a software guy :-o

[maggotsBrain]

Yes, I think you're right but I was not sure if plugging it was compulsory. Now I think it is, thanks.

I have a more specific question: the manual indicates that the chassis of the 6361 must be grounded. I use a NRSE (Non-referenced single ended) channel with a ground-referenced source, so I can't understand the utility of this chassis ground. Is it just a security measure in case of a static electrical choc that could damage the device or is it for some other reason?

[gaving · Accepted solution]

Yeah, like the manual says "For EMC Compliance"...

USB devices have to have a separate connection for this since they do not ground themselves directly from the power plug... (and they do not inherit device grounding from a chassis, like PXI, or from the computer, like PCI)

[maggotsBrain]

And would you know a way to do this properly, so that it does not look unprofessional?

[gaving]

My only suggestion would be to connect to another earth grounded device, if you have one, in your system. (something that has a earth ground screw and has a three-prong connection to the US wall outlet).

Does anyone else have a better solution?

[maggotsBrain]

I just do not understand why I have to ground it because it should already be through the power supply cable. If not, why isn't it? I am a bit confused.

[JaredRo]

Hi maggotsBrain,

I believe the power supply for the USB-6361 only has 2 prongs.  If this is the case, the chassis is not grounded via the power cable and should be manually grounded based on the User Manual instructions to ensure the device complies to EMC standards.