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Chapter 2 Function Reference — AI_Mux_Config
NI-DAQ FRM for PC Compatibles 2-10
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National Instruments Corporation
AI_Mux_Config
Format
status = AI_Mux_Config (deviceNumber, numMuxBrds)
Purpose
Configures the number of multiplexer (AMUX-64T) devices connected to the MIO and AI
devices and informs NI-DAQ of the presence of any AMUX-64T devices attached to the
system (MIO and AI devices only).
Parameters
Input
Parameter Discussion
numMuxBrds is the number of external multiplexer devices connected.
0: No external AMUX-64T devices are connected (default).
1, 2, 4: Number of AMUX-64T devices connected.
Using This Function
You can use an external multiplexer device (AMUX-64T) to expand the number of analog
input signals that you can measure with the MIO and AI device. The AMUX-64T has 16
separate four-to-one analog multiplexer circuits. One AMUX-64T reads 64 single-ended
(32 differential) analog input signals. You can cascade four AMUX-64T devices to permit up
to 256 single-ended (128 differential) analog input signals to be read through one MIO or AI
device. Refer to Chapter 1, Introduction to NI-DAQ, of the NI-DAQ User Manual for PC
Compatibles. See Chapter 10, AMUX-64T External Multiplexer Device, in the DAQ
Hardware Overview Guide for more information on using the AMUX-64T.
AI_Mux_Config configures the number of multiplexer devices connected to the MIO or AI
device. Input channels are then referenced in subsequent analog input calls (
AI_VRead,
AI_Setup, and DAQ_Start, for example) with respect to the external AMUX-64T analog
input channels, instead of the MIO and AI device onboard channel numbers. You need to
execute the call to
AI_Mux_Config only once in an application program.
Name Type Description
deviceNumber i16 assigned by configuration utility
numMuxBrds i16 number of external multiplexer devices