Appendix D Common Questions
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National Instruments Corporation D-3 VXI/VME-PCI8022 for Solaris
Are the PCI-MXI-2 and the VXI-MXI-2 two devices or one with
respect to the VXIbus?
Both the PCI-MXI-2 and the VXI-MXI-2 are unique VXIbus devices
with their own logical addresses. However, the MXIbus allows the
computer to behave as if it is inside the chassis with the VXI-MXI-2 by
transparently converting PCI bus cycles to MXIbus cycles to VXIbus
cycles, and vice versa.
I have a system that requires rugged chassis and bulkhead cables.
Can I still use MXIbus?
Yes, National Instruments sells MXIbus bulkhead cables. Contact
National Instruments for further information.
What kind of signal is CLK10 and what kind of signal do I need for
an external CLK10?
CLK10 is a differential ECL signal on the VXIbus backplane. However,
the oscillator for the VXI-MXI-2 and the EXTCLK input from the front
panel use TTL. Therefore, you need to supply a TTL level signal for
EXTCLK and our voltage converters will convert the signal to
differential ECL.
CLK10 is not applicable to VME.
What is the accuracy of the CLK10 signal?
The CLK10 generated by the VXI-MXI-2 is 100 ppm (0.01%) as per the
VXIbus specification. If you need a more accurate CLK10 signal, you
can use the EXTCLK input at the front of the VXI-MXI-2.
CLK10 is not applicable to VME.
Whenever I try to unload the PCI-MXI-2 driver, I receive the
following message:
Cannot unload the module: Device Busy.
I have no NI-VXI programs running. How can I unload the driver?
When you execute the function InitVXIlibrary(), NI-VXI spawns a
separate process to handle asynchronous events from the PCI-MXI-2.
When your application terminates, this process will still be active. Since
this process uses the PCI-MXI-2 driver, the driver cannot be unloaded.
To terminate the process, run resman. After running resman, you
should be able to unload the driver normally.