Chapter 2
Using the NI 447X
©
National Instruments Corporation
2-11
5.
Set the parameters as follows:
•
Channel—Select the input channel you are using.
•
Sample Rate (Hz)—Enter a sampling rate that is at least twice the
highest frequency component of your input signal.
•
Data Mode—Select
Continuous
.
•
Y Scale Mode—Select
Auto Scale
.
6.
Click
Start
to begin a continuous signal acquisition.
The Test Panel window displays a graph of the signal you input.
Field Wiring Considerations
Environmental noise can affect the accuracy of measurements made with
the NI 447
X
if you do not take proper care when running signal wires
between signal sources and the device. For more information, refer to the
NI Developer Zone document,
Field Wiring and Noise Considerations for
Analog Signals
, at
ni.com/zone
.
The following recommendations apply mainly to AI signal routing to the
NI 447
X
although they also apply to signal routing in general.
Minimize noise pickup and maximize measurement accuracy by taking the
following precautions:
•
Route signals to the device carefully. Keep cabling away from noise
sources. The most common noise source in a DAQ system is the video
monitor. Separate the monitor from the analog signals as far as
possible.
•
Separate NI 447
X
signal lines from high-current or high-voltage lines.
These lines can induce currents in or voltages on the NI 447
X
signal
lines if they run in parallel paths at a close distance. To reduce the
magnetic coupling between lines, separate them by a reasonable
distance if they run in parallel, or run the lines at right angles to each
other.
•
Do
not
run signal lines through conduits that also contain power lines.
•
Protect signal lines from magnetic fields caused by electric motors,
welding equipment, breakers, or transformers by running them through
dedicated metal conduits.
