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Chapter 2
Using the NI PXIe-4300
Window Triggering
A window trigger occurs when an analog signal either passes into (enters) or passes out of
(leaves) a window defined by two levels. Specify the levels by setting a value for the top and
bottom window boundaries. Figure 2-15 demonstrates a trigger that acquires data when the
signal enters the window. You can also program the trigger circuit to acquire data when the
signal leaves the window.
Figure 2-15.
Window Triggering
Digital Input Triggering
You can configure the NI PXIe-4300 device to start or pause an acquisition in response to a
digital trigger signal from either PFI <0, 1>, PXIe_DSTAR <A, B>, PXI_Trig <0..7>, or
PXI_STAR. The trigger circuit can respond to a rising, falling, or level sensitive signal, in one
of the following three modes:
•
Start—Begins an acquisition when trigger is met.
•
Reference—A certain number of pre-trigger and post-trigger samples are specified around
the trigger.
•
Pause—Acquisition is put on hold when trigger is met (level sensitive only).
In addition, the trigger circuit provides a programmable filter to help with noisy trigger signals.
The filter checks that the trigger condition is met for different time intervals before triggering.
The filter can select from 90 ns, 5.12
μ
s, 2.56 ms, or a custom defined time interval. For
information about configuring digital filters, refer to the
NI-DAQmx Help
.
TB-4300/B/C Accessory
The TB-4300/B/C terminal blocks provide screw terminals for access to the module.
•
The TB-4300 is strictly a voltage feedthrough terminal block.
•
The TB-4300B provides 30x attenuation to the input voltage with additional high-voltage
protection circuitry and expands the range of the NI PXIe-4300 to 300 V.
•
The TB-4300C provides 50
Ω
resistors between the AI+ and AI- terminals to convert
current to voltage for current measurements.
Refer to the
NI PXIe-4300 and TB-4300/B/C User Guide and Terminal Block Specifications
for
more information about the TB-4300/B/C terminal block accessory.
Window Top
Window Bottom
An
a
log Comp
a
ri
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on
Reference Trigger
