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.
24 VDC
A1
B1
A8
B8
IOV
IOG
IOV
IOG
IOV
IOG
IOV
IOG
A1
B1 C1
D1
A8
B8 C8
D8
IN1
IN2
IN3
IN4
NC
NC
NC
NC
SHT1+
SHT2+
SHT3+
SHT4+
IOV2 IOG2 SHT2- Input2-
IOV1 IOG1 SHT1- Input1-
IOV3 IOG3 SHT3- Input3-
IOV4 IOG4 SHT4- Input4-
Additional I/O
Power Supply
Unit*1
A1
B1
A8
B8
SHLD
SHLD
SHLD
SHLD
SHLD
SHLD SHLD
SHLD
SHLD SHLD
SHLD
SHLD SHLD
SHLD
Shield
Connection Unit
NX-TBX01
Use a two-conductor
shielded twisted-pair
cable.
Use a two-conductor
shielded twisted-pair
cable.
Use a three-conductor
shielded twisted-pair
cable.
Ground of
100 Ω or less
High-speed Analog Input Unit
NX-HAD401
Two-wire sensor
Three-wire sensor
Output device
Shield
Shield
Shield
Input+
Input-
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 Installation and Wiring
4 - 26
NX-series Analog I/O Units User’s Manual for High-speed Analog Input Units (W592)
