Chapter 5
Using the SCXI-1521/B
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time. For continuous acquisition, you must use a while loop around the
acquisition components even if you configured the task for continuous
acquisition using MAX or the DAQ Assistant. For continuous and buffered
acquisitions, you can set the acquisition rate and the number of samples to
read in the DAQ Assistant or programmatically in your application. By
default, the clock settings are automatically set by an internal clock based
on the requested sample rate. You can also select advanced features such as
clock settings that specify an external clock source, internal routing of the
clock source, or select the active edge of the clock signal.
Configuring Channel Properties
All ADEs used to configure the SCXI-1521/B access an underlying set of
NI-DAQmx properties. Table 5-1 shows some of these properties. You can
use Table 5-1 to determine what kind of properties you need to set to
configure the module for your application. For a complete list of
NI-DAQmx properties, refer to your ADE help file.
Note
You cannot adjust some properties while a task is running. For these properties, you
must stop the task, make the adjustment, and re-start the application. Figure 5-1 assumes
all properties are configured before the task is started.
Table 5-1.
NI-DAQmx Properties
Property
Short Name
Description
Analog Input»General Properties»
Advanced»Range»High
AI.Rng.High
Specifies the upper limit
of the input range
Analog Input»General Properties»
Advanced»Range»Low
AI.Rng.Low
Specifies the lower limit
of the input range
Analog Input»General Properties»
Signal Conditioning»Bridge»
Shunt Cal»Shunt Cal Enable
AI.Bridge.ShuntCal.Enable
Specifies whether to place
the shunt calibration
resistor across one arm of
the bridge
Analog Input»General Properties»
Signal Conditioning»Excitation»
Value
AI.Excit.Val
Specifies the amount of
excitation in volts
Analog Input»General Properties»
Signal Conditioning»Bridge»
Nominal Resistance
AI.Bridge.NomResistance
Specifies in ohms the
resistance of the bridge in
an unloaded condition
