Programming instructions

Chapter 11 AMUX-64T External Multiplexer Accessory
© National Instruments Corporation 11-3 DAQ Hardware Overview Guide
AMUX-64T accessory B are multiplexed together into MIO or AI device
channel 0. Notice that the MIO or AI device scans the first four channels on
accessory A, followed by the first four channels on accessory B.
If four AMUX-64T devices are attached to the MIO or AI device, you must
scan 16 AMUX-64T channels for every MIO or AI device input channel.
For example, channels 0 through 3 on AMUX-64T accessory A, channels
64 through 67 on AMUX-64T accessory B, channels 128 through 131 on
AMUX-64T accessory C, and channels 192 through 195 on accessory D
are multiplexed together into MIO or AI device channel 0. Notice that the
MIO or AI device scans the first four channels on accessory A, followed by
the first four channels on accessory B, the first four channels on accessory
C, and, finally, the first four channels on accessory D.
The order in which the MIO or AI device scans channels depends on the
scan channel sequence specified in the NI-DAQ function
SCAN_Setup or
LabVIEW
AI_Config.vi or AI_Group_Config.vi. This scan
sequence is an array of MIO or AI device onboard channel numbers that
indicates the order in which the MIO or AI device onboard channels are
scanned. The scanning order on the AMUX-64T, however, is fixed.
Table 11-3 shows the order in which the AMUX-64T channels are scanned
for every MIO or AI device input channel for different AMUX-64T
configurations.
Table 11-3. AMUX-64T Scanning Order for Each MIO or AI Device Input Channel
MIO
or AI Device
Channel
AMUX-64T Channels
One
Accessory
Two Accessories Four Accessories
Accessory
A
Accessory
A
Accessory
B
Accessory
A
Accessory
B
Accessory
C
Accessory
D
0 0–3 0–3 64–67 0–3 64–67 128–131 192–195
1 4–7 4–7 68–71 4–7 68–71 132–135 196–199
2 8–11 8–11 72–75 8–11 72–75 136–139 200–203
3 12–15 12–15 76–79 12–15 76–79 140–143 204–207
4 16–19 16–19 80–83 16–19 80–83 144–147 208–211
5 20–23 20–23 84–87 20–23 84–87 148–151 212–215
6 24–27 24–27 88–91 24–27 88–91 152–155 216–219
7 28–31 28–31 92–95 28–31 92–95 156–159 220–223
8 32–35 32–35 96–99 32–35 96–99 160–163 224–227