Which optocoupler model should I use to optically isolate digital counter inputs in a PCI-7041/6040 E?

[pablomendana]

Hello.
I'm trying to use quadrature encoders with a PCI-7041/6040 E board. I've read Application Note 084 ("Using Quadrature Encoders with E Series DAQ Boards") from NI and now I have built the system proposed (with the LS7084 clock converters). In that note, an optical isolation for A and B signal lines between encoder and electronical components (DAQ board and PC) is recommended. This signals are expected to be pulse trains with an amplitude of 5V and a maximum frequency of 50kHz (DAQ board inputs are TTL).
Which optocoupler model best fits this system?
Thanks!

[Jorge M.]

Hello Pablo,

here at NI we don't have exact specs regarding optocouplers, so my suggestion is to ask the manufacturers. As you mention, the only relevant specs about the system would be the bandwidth and voltage levels, so I guess it's rather straightforward to find a suitable model. Here is a nice list of manufacturers:

http://www.interfacebus.com/Analog_Opto_Couplers.html

Regards,

JorgeM.