Omron NSH5 - 10-2010 Operation Manual page 82

Connection Method
RS-422A Wiring
Note
Ground and Shield Wiring
58
RS-422A Terminal Block on
Removable Box
Name Pin No.
8
Functional ground
SDB 3
SDA 4
RS-422A
RDB
Connector 1
RDA 2
(8-pin terminal block)
Use twisted-pair wires for SDB and SDA, and for RDB and RDA.
(1) Ground the shield only to the host (PLC) to prevent malfunctions due to
ground potential differences.
(2) Recommended cables: TKVVBS4P-03 (100 m Tachii Electric Wire) or
AWG22 shielded cable.
Perform the following connections, shield wiring, and grounding in any com-
munications system using the Removable Box. Incorrect connections may
cause a host communications error.
• Connecting the Removable Box D-Sub Connector
Be sure to fasten the screws on both sides of the D-Sub connector. If
these screws are not fastened, the NSH5 PT's functional ground terminal
and the Removable Box's FG will not be connected.
• Ground Line Wiring
The Removable Box is equipped with a functional ground (
1. Normally, ground the Removable Box as shown in Figure A on the fol-
lowing page.
• Connect the ground terminals on all Units and the functional ground,
and ground the line at one location to 100 Ω or less.
• Short the PLC's LG terminal and the GR terminal.
• The ground wire must be 2 mm
• For detailed grounding instructions, refer to the operation manual for
the Communications Unit.
2. If a source of noise, such as a motor or inverter, is grounded to the same
panel, do not ground the Removable Box's functional ground terminal
( ), as shown in the Figure B.
• RS-422A Cable Shield Wiring
Be sure to connect the shield on the RS-422A cable. If the shield is not
connected, a host communications error may occur.
When connecting the ground terminals on all Units and the functional
ground, and grounding the line at one location to 100 Ω or less, connect
the shield only at one end of each line, as shown in Figure A.
If the Removable Box's functional ground terminal is not grounded, con-
nect the shield at both ends of each line, as shown in Figure B.
If a CJ1W-CIF11 is also connected in the system, connect the lines and
shield as shown in Figure B.
PLC
(See
Pin No. Name
(See note 1.) note 2.)
Shield ground terminal
SD+
SD−
RD+
RD−
Shield
2
or larger.
Section 4-5
RS-422A
Connector
).