National Instruments PCI-4451, PCI-4452 - page 55

Chapter 4 Signal Connections
© National Instruments Corporation 4-25 PCI-4451/4452 User Manual
The following recommendations apply for all signal connections to digital
signal routing from your PCI-4451/4452 device:
• The digital output signal integrity is greatly influenced by the length of
the cable being driven. Minimize cable lengths and use schmitt-trigger
devices to deglitch signals. Further conditioning may be required to
create a clean signal.
• Always tr y to couple a grou nd with a signal to minimi ze noise pi ckup
and radiation.
The following recommendations apply for all signal connections to your
PCI-4451/4452 device:
• Separate PCI-4451/4452 device signal lines from high-current or
high-voltage lines. These lines can induce currents in or voltages on
the PCI-4451/4452 device signal lines if they run in parallel pat hs 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 li nes thro ugh cond ui ts th at als o co ntai n p ower 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.
User.book Page 25 Tuesday, April 14, 1998 10:20 AM