National Instruments SCXI-1121 Manuel D’Utilisation

5.

Write binary 

101S 1100

 to the HSCR.

6.

Write binary 

101S 1110

 to the HSCR.

7.

Write binary 

101S 1111

 to the HSCR.

In the preceding steps, S = 0 if you want the scanning to repeat when the 
end of the list is reached. S = 1 if you want the circuitry to shut down after 
a single scan.

When you are writing multiple entries to the same register, for example, 
repetitive writes to the HSCR or several FIFO entries, it is important that 
SS*13 or SS*14 go inactive (high) between each entry. Select another slot 
or toggle the SLOT0SEL* line to temporarily deassert the appropriate SS* 
line.

If consecutive scan list entries access an SCXI-1121, the module will reload 
the MUXCOUNTER with the starting channel after each entry. Thus, two 
entries with counts of two for one module will yield different behavior than 
one entry with a count of four.

For multiple-chassis scanning, program each Slot 0 with dummy entries to 
fill the sample counts when the data acquisition board is accessing other 
chassis. Use Slot 13 as the dummy entry slot.

See 

 at the end of this chapter.

At this point, you should now continue from where you left off in the

 section of this chapter. 

Perform the following steps given in your data acquisition board user 
manual.

•

–

Enable the scanning data acquisition operation.

–

Apply a trigger.

–

Service the data acquisition operation.

•

Lab-PC User Manual, Lab-PC+ User Manual, and PC-LPM-16 User 
Manual

–

Start and service the data acquisition operation.

•

–

Program the sample-interval counter.

–

Service the data acquisition operation.