Optional Grounding Arrangements - Brainboxes CC-368 User Manual

Optional Grounding Arrangements.

Configuration B)
Configuration A) The circuit common of the equipment is connected to protective ground, at one point only by a
100 Ω, ±20% resistor with a power dissipation rating of 1/2W. An additional provision may be made for the resistor to be
bypassed with a strap to connect signal common and protective ground directly together when specific installation
conditions necessitate.
PCI Quad 422/485 Card
Note: The receiver end of MAIN line terminated in characteristic impedance, stubs off
the main not terminated.
Proper operation of the cable circuit, according to TIA EIA:
that the cable ground shield is not connected directly to the equipment ground shield. A
current limiting resistor should be used in series with the shield to avoid possible large
current flow due to differences in ground potential. Any one of the methods shown
below can do this.
Configuration A)
GWG
GWG
SG = Signal Ground Interchange circuit.
GWG = Green wire ground of power system.
= Protective ground of frame ground.
= Circuit ground or circuit
100Ω
(1/2) W
common.
Chapter 10 Optional RS422/485 Operation x 54
485 A (1995) requires
SG
SG