Omron Sysmac NX Series User Manual page 94

4 Installation and Wiring
However, do not connect the end of the shield anywhere on the output device. If you ground the shield
on both the High-speed Analog Input Unit side and the output device side, the Unit becomes suscepti-
ble to noise induced due to ground loops.
When you ground the end of the shield, you can use the NX-TBX01 Shield Connection Unit to ground
more than one shield.
A wiring example is shown below.
Additional I/O
Power Supply
Unit *1
A1
IOV
IOG
24 VDC
IOV
IOG
A8
Connect the shield of cable to the SHLD terminal on the Shield Connection Unit.
And ground the functional ground terminal on the Shield Connection Unit to 100 Ω or less.
*1. Besides the Additional I/O Power Supply Unit, some other Units can supply I/O power to the NX bus. For ex-
ample, you can use a Connected Communications Coupler Unit. If you use this Unit to supply I/O power to the
High-speed Analog Input Units, the Additional I/O Power Supply Unit is unnecessary. The Additional I/O Pow-
er Supply Unit is also unnecessary if you do not use the trigger inputs of the High-speed Analog Input Units.
Precautions for Correct Use
To ensure this NX Unit is kept in the best operating condition, observe the following points when
wiring to avoid the effects of the noise.
• Use a shield wire (2 conductors, twisted wire) or a shield wire (3 conductors) as the analog
input connection line for each input.
• Wire the input connection lines and power lines (e.g., AC power supply lines or power lines)
separately. Do not place such lines in the same duct.
• Insert a noise filter into the power supply input section if noise comes from power supply lines
when using the same power supply to power an electrical welder or an electric discharge ma-
chine, or there is a high-frequency source nearby.
4 - 26
Shield
Connection Unit
NX-TBX01
B1 A1 B1
IOV SHLD SHLD
SHLD SHLD
IOG SHLD SHLD
SHLD SHLD
IOV SHLD SHLD
SHLD SHLD
IOG SHLD SHLD
B8 A8 B8
Ground of
100 Ω or less
NX-series Analog I/O Units User's Manual for High-speed Analog Input Units (W592)
Shield
High-speed Analog Input Unit
NX-HAD401
A1 B1 C1 D1
IN1 NC SHT1+ Input1+
IOV1 IOG1 SHT1- Input1-
IN2 NC SHT2+ Input2+
IOV2 IOG2 SHT2- Input2-
IN3 NC SHT3+ Input3+
IOV3 IOG3 SHT3- Input3-
IN4 NC SHT4+ Input4+
IOV4 IOG4 SHT4- Input4-
A8 B8 C8 D8
Shield
Shield
Output device
Input+
Input-
Use a two-conductor
shielded twisted-pair
cable.
Two-wire sensor
Use a two-conductor
shielded twisted-pair
cable.
Three-wire sensor
Use a three-conductor
shielded twisted-pair
cable.