04-26-2010 01:09 PM
I have a NI USB-6210 and the outputs of the +5V and the digital outputs are between 6.5 and 7 volts. This may damage some of the logic I intend to connect to the DAQ. What may be the cause of, and what is the solution to this problem?
Thanks
04-26-2010 08:59 PM
04-27-2010 09:37 AM
Is this measured between the +5V pin and one of the digital ground pins? Also, are you doing anything else with the card when you read between these terminals, like reading on AI?
Regards,
04-27-2010 09:47 AM
I'm using a multimeter to measure between the 5V output and the digital ground. When I measured the output voltage of the USB port with the same multimeter it was giving me the 6.5-7 volts as well.
In another lab, with a different computer and multimeter the 5V output gave about 5 V. So it appears to be either the multimeter is wonky, or the DAQ is just passing through voltage it gets from the USB. As a last test I'm going to feed the 5V output into one of the analog inputs (since some of the tests I did in the other lab indicated that those readings are accurate) and that should answer whether it is the multimeter of if the DAQ is just doing a pass through.
Thanks for your suggestions!
04-27-2010 10:00 AM
Yep, the +5V pin comes straight off the USB port, though on some devices we do current limiting to keep the total draw off the USB port under the required 500 mA. If the computer is supplying a higher voltage, there isn't much we can do to correct it.
Best of luck!
04-27-2010 12:02 PM
Looks like it was a ghost in the machine. 5V output to analog input gives 5V dead on. Measurement with the same multimeter gives a little more than 5 V.
Go figure.
Thanks.