USB NI-8451

[Briton]

Hi 
I got an old USB 8451 box where GND pins on the connector and USB connector GND is shorted.
I also got a brand new one where the two connections id isolated from each other.

Is the deferens because the first one is defect or has NI changed this over time?

I have search the HW manual, but it gave me no answer.

Thanks in advance

Bjarne

[DanC12]

Hi Bjarne,

Depending on the age of your old USB 8451, I think it would be hard to find the documentation about the GND pins being shorted or if the circuit has changed. 

Is it affecting your measurements?

[Briton]

Hi

Newest update.
I was a measurement error that lead to state the was no connection between IO_GND and USB_GND.
I found the error on the failing NI-8154. 5V was faulty so resistance between GND and 5V was ~1 ohm.

Regards Bjarne