Advantech 48/24-Channel Digital Input/Output USB Module USB-4751/4751L Manuel d'utilisateur télécharger pdf (Page 22)

USB-4751/4751L User Manual 16

3.4 Field Wiring Considerations

• When you use USB-4751/4751L to acquire data from outside, noises in

the environment might significantly affect the accuracy of your mea-

surements if due cautions are not taken. The following measures will

be helpful to reduce possible interference running signal wires between

signal sources and the USB-4751/4751L.

• 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 in a right angle to the

power line to minimize the undesirable effect.

1 2 ... 17 18 19 20 21 22 23 24

Pas de commentaire

Advantech 48/24-Channel Digital Input/Output USB Module USB-4751/4751L Manuel d'utilisateur Page 22