Chapter 3 Signal Connections 25
3.6 Field Wiring Considerations
When you use the PCI-1710/1710HG card to acquire outside data,
environmental noise can seriously affect the accuracy of your mea-
surements if you don’t provide any protection. The following sugges-
tions will be helpful when running signal wires between signal sources
and the PCI-1710/1710HG card.
• Please make sure that you have carefully routed signal cables to the
card. You must separate the cabling from noise sources. Try to keep
video monitors far away from the analog signal cables, because
these are a common noise source in a PCI data acquisition system.
• If you want to reduce common-mode noise, try to use differential
analog input connections.
• If you do not want your signals to be affected when travelling
through areas with high electromagnetic interference or large
magnetic fields, try the following routing techniques: Use
individually shielded, twisted-pair wires to connect analog input
signals to the board, i.e. the signals connected to the High and Low
inputs are twisted together and covered with a shield. Finally,
connect the shield only to one point at the signal source ground.
• Make sure that your signal lines do not travel through conduits,
because these may contain power lines. Also, keep your signals
far from electric motors, breakers or welding equipment, as these
can create magnetic fields.
• Keep a reasonable distance between high-voltage (or high-current)
lines and signal cables connected to the PCI-1710/1710HG card if the
cables run parallel, or route signal cables at right angles to high
voltage/current cables.
• In addition to outside noise, the transmitted signals themselves
can affect the card's performance. We suggest connecting signal
sources to the card using the PCL-10168 shielded cable in order to
avoid this kind of interference