Rockwell-automation 1788-CNCHKR ControlNet NetChecker User Manual Manual do Utilizador descarregar pdf (Página 23)

ControlNet NetChecker 23

Rockwell Automation Publication 1788-UM001B-EN-P - August 2012

Impedance mismatches cause reflections on the media:

• Network not correctly terminated.

• Impedance of coaxial cable not equal to 75

Ω.

• High resistance of contact in connectors.

• Incorrect network architecture.

Effect of Attenuation on Signal Edges

Excessive attenuation causes loss of signal:

• Poor quality coaxial cable

– Resistance too high

– Losses in dielectric

• Overloaded network

– Too long trunk seg m ent

– Excessive number of nodes per segment

• Impedance mismatches

IMPORTANT

Each coaxial segment must be terminated with a 1786-TCAP terminator at each end.

2.000 V/D

100 ns/DIV

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Rockwell-automation 1788-CNCHKR ControlNet NetChecker User Manual Manual do Utilizador Página 23