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Common Questions
Appendix I
VXIpc-486 Model 500 Series
I-2
© National Instruments Corporation
4. Make sure that the VXIpc-486 is seated properly in the mainframe.
5. Power on the mainframe and observe whether the SYSFAIL and FAILED LEDs become
unlit after running
VXIINIT
.
Refer also to Appendix C, Front Panel Indicators.
Why is the TURBO light never lit on the VXIpc-486 Model 500 Series?
The TURBO light is never lit on the VXIpc-486 Model 500 Series because models in this series
do not have a TURBO or enhanced CPU speed. The Model 500 Series computers are always
running the CPU at the fastest possible speed. However, the VXIpc-486 Model 200 Series—
Models 200 and 240—have the option of running the CPU at a slower speed if you change a
parameter in the BIOS
Setup
utility. If you choose the slower speed for the Model 200 Series
computers, the TURBO LED will not be lit. Because the Model 500 Series and the Model 200
Series share the same front panel faceplate and LEDs, the TURBO LED exists on the Model 500
Series, but it is never lit.
I have a system that requires ruggedized chassis and bulkhead cables. Can I still use
MXIbus to have multiple VXIbus chassis?
Yes, National Instruments sells MXIbus bulkhead cables. Contact National Instruments and ask
for Technical Note 30, Planning a MXIbus System Using MB Series Bulkhead Cables, which
describes the cables and discusses how to design the system.
Can I access 32-bit registers in my VXIbus system from the VXIpc-486?
Yes. Although the VXIpc-486 supports the ISA bus, it does not use the bus for communication
with the VXIbus backplane. National Instruments has a specialized bus dedicated to the
communication to the VXIbus backplane. This bus is a full 32 bits wide, and you can use it for
D32 accesses.
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 backplane. However, the oscillator for the VXIpc-486
and the EXTCLK input from the front panel use TTL. Therefore, you need to supply a
TTL-level signal for EXTCLK. Our voltage converters convert the signal to differential ECL.
What is the accuracy of the CLK10 signal?
The CLK10 signal generated by the VXIpc-486 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 VXIpc-486.