Can I use an SCXI chassis with a USB-625x mass termination?

[Joonam]

 Below, the document says we cannot use an SCXI chassis with a USB-625x.

 When I see the M series User Manual attached below(Appendix A Device-Specific Information), I can use an SCC carrier with a USB-625x mass termination using a SCH-68-68-EP cable. Then, why can't I use an SCXI chassis with a USB-625x mass termination? I can connect signals from an SCXI chassis to USB-625x mass termination using this cable and SCXI-1394. Is there something more that I must considerate? If there is some reason that I cannot use an SCXI chassis with a USB-625x mass termination, then let me know something.

http://digital.ni.com/public.nsf/websearch/0CD1B65EE53C5A03862571C600763439?OpenDocument

Regards.

[Neil_S.]

Joonam,

Thanks for posting to the NI forums.  I believe the KnowledgeBase article is correct.  The USB-625x cannot be used with an SCXI chassis.  I believe this is due to the longer latency with single point digital I/O which the DAQ device must use to configure the SCXI.  The USB-625x has a much greater initial latency due to the limitations of the USB bus.  However, all of this is a theory.  I am going to speak with R&D to see if I can dig up any more details.  I will let you know.

Regards,

Neil S.
Applications Engineer
National Instruments

[Tom_W_[DE]]

Hi Joonam-

As Neil mentioned, the manual is correct in this case.  The combination of USB M Series and SCXI is not supported by NI-DAQmx.

Thanks-

Message Edited by Tom W [DE] on 10-30-2006 12:52 PM