Programming instructions

© National Instruments Corporation 11-1 DAQ Hardware Overview Guide
11
AMUX-64T External
Multiplexer Accessory
This chapter contains overview information on the AMUX-64T accessory.
AMUX-64T External Multiplexer Accessory
An AMUX-64T external multiplexer accessory expands the number
of analog input signals that the MIO or AI device can measure.
The AMUX-64T has 16 separate four-to-one analog multiplexer
circuits. One AMUX-64T accessory can multiplex up to 64 analog input
signals. You can cascade four AMUX-64T Accessories to permit up to
256 single-ended (128 differential) signals to be multiplexed by one MIO
or AI device. Table 11-1 shows the number of channels available on the
MIO or AI device with an external multiplexer.
The NI-DAQ function
AI_Mux_Config and LabVIEW AI_Config.vi or
AI_Group_Config.vi configures the number of multiplexer devices
connected to the MIO or AI device. You then use the input channels
in subsequent data acquisition calls with respect to the external
AMUX-64T analog input channel numbers rather than the MIO or
AI device onboard channel numbers. For example, with one external
device, channel can have a value of 0 through 63 (single-ended),
or 0 through 31 (differential). With two or four AMUX-64T devices,
Table 11-1.
Analog Input Channel Range
Number of External
Multiplexer
(AMUX-64T) Devices
Channel Range
Single-Ended Differential
0 0–15 0–7
1 0–63 0–31
2 0–127 0–31, 64–95
4 0–255 0–31, 64–95, 128–159,
192–223