User manual

PCI-1752 User Manual 22
3.4 Field Wiring Considerations
When you use the PCI-1752U/PCI-1752USO to acquire data from out-
side, noises in the environment might significantly affect the accuracy of
your measurements if due cautions are not taken. The following measures
will be helpful to reduce possible interference running signal wires
between signal sources and the PCI-1752U/PCI-1752USO.
• The signal cables must be kept away from strong electromagnetic
sources such as power lines, large electric motors, circuit breakers
or welding machines, since they may cause strong electromagnetic
interference. Keep the analog signal cables away from any video
monitor, since it can significantly affect a data acquisition system.
• If the cable travels through an area with significant electromagnetic
interference, you should adopt individually shielded, twisted-pair
wires as the analog input cable. This type of cable has its signal
wires twisted together and shielded with a metal mesh. The metal
mesh should only be connected to one point at the signal source
ground.
• Avoid running the signal cables through any conduit that might
have power lines in it.
• If you have to place your signal cable parallel to a power line that
has a high voltage or high current running through it, try to keep a
safe distance between them. Or you should place the signal cable at
a right angle to the power line to minimize the undesirable effect.
• The signals transmitted on the cable will be directly affected by the
quality of the cable. In order to ensure better signal quality, we rec-
ommend that you use the PCL-10250 shielded cable.