Advantech MIC-3758DIO, User Manual

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MIC-3758DIO User Manual 20
Figure 3.5: Isolated Digital Output Connection
3.5 Field Wiring Considerations
When you use MIC-3758DIO to acquire data from outside, noises in the
environment might significantly affect the accuracy of your measure-
ments if due cautions are not taken. The following measures will be help-
ful to reduce possible interference running signal wires between signal
sources and MIC-3758DIO.
• 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 inter-
ference. 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 dis-
tance between them. Or place the signal cable at a right angle of the
power line to minimize the effect.