National Instruments 370551A-01 Manuale Utente

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Appendix D
Common Questions
© National Instruments Corporation
D-3
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 execute any of the NI-VXI utilities, I receive a 
message similar to this one: 
error in loading shared libraries: libnivxi.so: cannot 
open shared object file: no such file or directory
What does this error message mean?
This usually means that the application could not load the NI-VXI library. 
Check the environment variable 
NIVXIPATH
 and your 
/etc/ 
ld.so.conf
 file. 
NIVXIPATH
 should be set only to the directory where 
you installed NI-VXI (
/usr/local/nivxi
 by default). 
/etc/ld.so.conf
 should include the directory where you installed the 
NI-VXI library (
/usr/local/nivxi/lib
 by default). Run 
ldconfig
 to 
reread this file.