National Instruments 1128 用户手册

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Appendix E
Common Questions
E-2
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If you use the SCXI-1127/1128 to initiate the scan, make sure the 
DMM is waiting for a trigger before enabling scanning on the 
SCXI-1127/1128.
If you use the DMM to initiate the scan, enable scanning on the 
SCXI-1127/1128 before configuring the DMM to start taking 
measurements. This is the recommended method for scanning.
Be sure to check the return codes of the NI-SWITCH operation to 
ensure that there are no errors (negative values) or warnings (positive 
values). You can also use the NI-Spy utility, which is installed with 
NI-SWITCH, to check for error codes.
Verify that your code is correct. For reference, see the examples 
described in the NI-SWITCH Software User Manual. NI-SWITCH 
also ships with several examples in source code. Compare your 
algorithm to the ones in the examples.
Do I need to program the SCXI-1127/1128 myself?
The SCXI-1127/1128 comes with the NI-SWITCH driver software that 
exports the full functionality of the module. NI-SWITCH handles the 
complex issues of register writes to the module and operating system 
interfacing.
Can I plug a non SCXI-1127/1128 module into a slot that has a 
high-voltage analog backplane?
Yes. You can plug in a module that does not support the HVAB. The 
non-SCXI-1127/1128 module does not connect to the HVAB or the digital 
communication lines on the HVAB backplane adapter. 
Must I install the complete high-voltage analog backplane?
No. You do not have to install the complete backplane. There may be 
instances where it is necessary for a non SCXI-1127/1128 module to 
communicate to a device using a different backplane adapter. For example, 
using a separate digital module in parallel mode. In this case, you can 
remove that segment of the HVAB although it is important that you do not 
remove the section of the HVAB that is controlling the chassis.
Can I use the HVAB for matrix expansion?
Yes. You can use the HVAB backplane to connect the matrix rows together. 
For example you can create a 8 
× 16 matrix in a 4-slot chassis. First install 
four SCXI-1127/1128s into the chassis. Now you have four independent 
4
× 8 matrices. Now if you install the 2-slot HVAB-backplane adapter