Current is limited on the 5V output of ni usb -6289

[jul_b]

Hello,

I measured the current and the voltage of my ni usb-6289 5V output for differents loads. I thought this output could supply 1A but the voltage drop to 3.3V for a supplied current of 100 mA althought the board is powered by an externel power supply.Is it normal?

[Jean-Luc_D.]

Hello,

Yes it is a normal behaviour, you can see the digital I/O characteristics page 10 of this document : http://www.ni.com/pdf/manuals/371292g.pdf

Best regards

[AnalogKid2DigitalMan]

Spoiler

Jean-Luc:

I think he was referring to the +5V output pin, not the digital outputs. 1A is the spec.

There is a user-replaceable fuse on the USB devices. I am not sure if this is a poly-fuse or a traditional one (refer to the M-Series User manual). I have seen poly fuses fail in such manner.

-AK2DM

[jul_b]

Thank you for your reply. But so : 

what does usb devives 5V output 1A max mean ?

[Jean-Luc_D.]

It's the maximum current that can be delivered by the +5V pin. Check if the power supply meets the requirement.

Best regards

[sth]

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@jul_b wrote:

Thank you for your reply. But so : 

what does usb devives 5V output 1A max mean ?

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It means that the 5V output pin on the USB-6289 which is pin 14 on connector 1 is the only pin with high current.

The analog output can output 5 mA, the digital output as shown in the link show above.