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USB 6001 5v Digital Output

Hi all,

 

I have searched and read the other threads and on this and still find myself confused!

 

I am triggering Digital Output  P0.0 on my USB 6001 DAQ and was hoping to read 5vdc on my multimeter as I want to energise a 5vdc SSR. Unfortunately the max voltage I am reading is 3vdc, do i need to wire a pull up resistor into my circuit??

 

I was under the impression that my voltage would be 0v low and 5v high but perhaps i am wrong? can the output voltage be altered?

 

As always any feedback greatly appreciated,

Cheers 

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Hello,

 

It is not clear what you are doing.

Do you set High state of the P0.0?

Have you tried examples or MAX front panels?

Between what terminals you measured voltage?

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@FolanK wrote:

I am triggering Digital Output  P0.0 on my USB 6001 DAQ and was hoping to read 5vdc on my multimeter as I want to energise a 5vdc SSR. Unfortunately the max voltage I am reading is 3vdc, do i need to wire a pull up resistor into my circuit??


Sounds like a current limit issue.  The USB-6001 DIO lines have a maximum current of 4mA.  If your SSR needs more current on its input, your digital line voltage will sag.  You can try adding a pull-up resistor to give some more drive capability, but I would either look into a SSR that needs less input current or use a buffer chip that can supply more current.


GCentral
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Looks like the DO of 6001 can do only 3.3V (assumed typical since max is 3.6V). Under 1mA load, it can guarantee 2.8V when High.

santo_13_0-1620913988472.png

 

Taking this SSR as an example, you would need 7.5mA for proper triggering though it can turn ON upwards of 2.4V

Based on this, you are better off adding a transistor at the output to control the SSR (P0.0 -> Transistor -> SSR)

Santhosh
Soliton Technologies

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