Cutler-Hammer D320 PLC, User Manual

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D320 PLC User's Manual
Shielding Cabling
• When the wiring for the I/O module is more than 165 ft (50 m), shield the wire by installing it
in ferrous (steel) conduit and use shielded wire. Attach the conduit/shield to the ground at the
PLC ground terminal as shown below.
•
Separate the input and output module wiring, and power circuit cables. Make sure to properly
ground the shields of each cable directly to ground. Do not create a daisy chain of ground
jumpers over several feet and then pigtail one end lead to ground. This method allows
multiple ground current paths to exist and can induce noise.
Switching Noise/Crosstalk
•
The noise caused by the On/Off switching of the relay output module (especially on heavy
loads) could affect the CPU module and the communications module. If possible, avoid
installing the relay output module next to the CPU or the communication module (CCU,
SDU, link modules, etc.).
•
Do not use the AC power input to the PLC power supply as the input signal for the AC input
module. The waveform could be greatly distorted, due to the switching of the module.
Use shield wires,
or shield the wire
Ground (ground resistance
less than 100
Ω
)
Ground
terminal
COM
In
PLC
P
O
W
E
R
C
P
U
Relay output module
CCU or SDU module etc.
Communication module
Switch
A/C input module
COM
IN
AC input
Static
voltage
trans