Rs-422A/485 Connections; Grounding And Shielding Of The Cables - Omron NB3Q-TW00B Setup Manual

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RS-422A/485 Connections

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Grounding and Shielding of the Cables

When performing communications using RS-422A/485, carry out the connections, shielding and
grounding as follows:
Grounding wiring
The NB Unit has a functional grounding terminal (FG:
(1) Generally, make the grounding according to Fig. (a).
• Connect the grounding terminals (GR) of the devices and the functional grounding terminal
(
• Short-circuit the LG terminal and GR terminal of the PLC.
• Use a cable with a minimum of 2 mm
• For details about the connection methods, refer to the related communication Unit
manuals.
(2) As shown in Fig. (b), when the NB Unit, and noise source equipments such as motors and
inverters, etc. are installed on the same panel, do not ground the NB Unit's functional
grounding terminal (
Shielding of RS-422A/485 Cables
Be sure to shield the RS-422A/485 cables. Connect the grounding terminals (GR) of the devices and
the functional grounding terminals (
resistance 100Ω), carry out a single-end shielding according to Fig. (a).
If grounding is not done to the functional grounding terminal (
shown in Fig. (b).
Note In order to avoid malfunctions caused by interferences, shield the cables properly.
NB-series Programmable Terminals Setup Manual(V107)
), at only one point make a D-type grounding (Max. grounding resistance 100Ω).
).
), at only one point make a D-type grounding (Max. grounding
WWW.NNC.IR
).
2
for the grounding cable.
) of the NB Unit, shield both ends as
Appendices
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