National Instruments DAQ PCI E Series User Manual page 90

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point to the signal source ground. This kind of connection is
required for signals traveling through areas with large magnetic
fields or high electromagnetic interference.
• Route signals to the board carefully. Keep cabling away from noise
sources. The most common noise source in a PCI data acquisition
system is the video monitor. Separate the monitor from the analog
signals as much as possible.
The following recommendations apply for all signal connections to
your PCI E Series board:
• Separate PCI E Series board signal lines from high-current or
high-voltage lines. These lines can induce currents in or voltages on
the PCI E Series board 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 special metal conduits.
For more information, refer to the application note, Field Wiring and
Noise Consideration for Analog Signals, available from National
Instruments.
4-47
Chapter 4 Signal Connections
PCI E Series User Manual