National Instruments 321645c-01 用户手册
Chapter 2
Function Reference — SCXI_MuxCtr_Setup
NI-DAQ FRM for PC Compatibles
2-348
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National Instruments Corporation
Using This Function
You can use this function to synchronize the scan list that NI-DAQ has loaded into the
mux-gain memory of the DAQ device and the SCXI module scan list that NI-DAQ has loaded
into Slot 0 of the SCXI chassis. The total number of samples to be taken in one pass through
each scan list should be the same. Am9513-based MIO devices use counter 1 as the mux
counter. The Lab and 1200 Series and E Series devices have a dedicated mux counter.
mux-gain memory of the DAQ device and the SCXI module scan list that NI-DAQ has loaded
into Slot 0 of the SCXI chassis. The total number of samples to be taken in one pass through
each scan list should be the same. Am9513-based MIO devices use counter 1 as the mux
counter. The Lab and 1200 Series and E Series devices have a dedicated mux counter.
For example, for the following scan lists, a ctrValue of 8 causes NI-DAQ to take eight
samples for each MIO or AI scan list entry. The first two entries in the module scan list will
occur during the first entry of the MIO or AI scan list, at an MIO or AI gain of 5. The third
module scan list entry will occur during the second entry of the MIO or AI scan list, at an MIO
or AI gain of 10. Thus, NI-DAQ uses the ctrValue here to distribute different MIO or AI gains
across the module scan list, as well as to make the scan list lengths equal at 16 samples each.
samples for each MIO or AI scan list entry. The first two entries in the module scan list will
occur during the first entry of the MIO or AI scan list, at an MIO or AI gain of 5. The third
module scan list entry will occur during the second entry of the MIO or AI scan list, at an MIO
or AI gain of 10. Thus, NI-DAQ uses the ctrValue here to distribute different MIO or AI gains
across the module scan list, as well as to make the scan list lengths equal at 16 samples each.
Another example would use the same module scan list in the preceding table, but use as MIO
or AI scan list with only one entry for channel 0. In this case, a ctrValue of 16 would be
appropriate.
or AI scan list with only one entry for channel 0. In this case, a ctrValue of 16 would be
appropriate.
Table 2-33. SCXI Module Scan List
Module
Number of Samples
2
4
3
4
4
8
Table 2-34. MIO or AI Scan List
Module
Number of
Samples
Channel
Gain
2
4
0
5
3
4
0
10
4
8
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