National Instruments Measure Data Acquisition SCXI Analog Input

your data acquisition device. The multiplexed mode is the default and

recommended mode to use with SCXI. In the parallel mode, each SCXI

module is directly connected to one data acquisition device and each

analog input channel on a SCXI module is connected to a separate

analog input channel on the data acquisition device. Not all data

acquisition devices or SCXI modules support the parallel mode.

Consult your data acquisition hardware user manual for more

information.

SCXI Analog Input To configure channels on a SCXI analog input module in the DAQ task

configuration, first select the DAQ device in the main DAQ Tasks

dialog box to which the SCXI module is directly or indirectly

connected. Then, select the AI button to create an AI task or the Edit

button to modify an existing AI task. In the Analog Input

Configuration dialog box, specify the SCXI channel(s) you want to

acquire in the Channels field by entering a channel string. This channel

string provides information about the DAQ device channel, SCXI

chassis number, SCXI module number, and SCXI channel number. The

channel string has the following format:

ob0!scx!mdy!z

In the SCXI channel string, x represents the chassis number, y the

module number, and z the channel number.

‘ob0’ in the SCXI channel string indicates which onboard channel (on

the DAQ device) to use to acquire the data. In the SCXI multiplexed

mode (default mode), all SCXI channels from one SCXI chassis are

multiplexed onto one onboard channel. Usually, this is channel 0 (ob0

in the SCXI string), unless you are using more than one SCXI chassis;

in which case each additional chassis uses the next onboard channel

(i.e. Chassis 2 uses onboard channel 1, and so on).

‘scx’ represents the chassis number where x is replaced by the actual

number (e.g. sc1). The chassis are numbered starting with 1 and the

chassis number is assigned in the NI-DAQ configuration utility.

‘mdy’ represents the module number where y is replaced with the

actual number (e.g. md2). The modules are numbered 1 through

each SCXI chassis with module 1 being in the left-most slot of the

SCXI chassis and module

in the right-most slot.