dio pin and optocoupler problem

[pranitapatil]

hi ,i am using pci 6014 DAQ card for my project.
now i am trying to take optocoupler o/p on dio line of DAQ card.
but the problem is when i checked the optocoupler module seperately it works fine .when i connect it to the dio pin of DAQ card the voltage ot dio pins droup to 0.7v and remains constant even if o/p of optocoupler is chaged. why is it so?
is it problem if impedance matching?
if yes tell me solution plz
i am sending document related to pci 6014. you can refer the same.

 

[IanP]

Pin has to be set as input - hope you've done that so far ..
Next, output from an optocoupler is an OC [Open-Collector] configuration, so to read a "1" you need an external (or if the card supports that feature - internal) pullup resistor .. somthing like 4.7kΩ - 10kΩ should do ..

Rgds,
IanP

 

[hakeen]

Addition to Ianp's point, be careful if your external pull-up resistor (assuming you used) is too high.

Could you make a sketch of your connection?

Cheers