Mitsubishi MELSEC FX3U Series Handbook page 7

[WIRING PRECAUTIONS]
CAUTION
● Do not supply power to the [24+] and [24V] terminals (24 V DC service power supply) on the CPU
module or extension modules. Doing so may cause damage to the product.
● Perform class D grounding (grounding resistance: 100 Ω or less) to the grounding terminal on the
CPU module or extension modules with a wire 2 mm
Do not use common grounding with heavy electrical systems (refer to the User's Manual (Hardware)
for the CPU module to be used).
● Connect the power supply wiring to the dedicated terminals described in this manual. If an AC power
supply is connected to a DC input/output terminal or DC power supply terminal, the PLC will burn out.
● Do not wire vacant terminals externally. Doing so may cause damage to the product.
● Install module so that excessive force will not be applied to terminal blocks, power connectors, I/O
connectors, communication connectors, or communication cables. Failure to do so may result in wire
damage/breakage or PLC failure.
● Make sure to observe the following precautions in order to prevent any damage to the machinery or
accidents due to malfunction of the PLC caused by abnormal data written to the PLC due to the
effects of noise.
- Do not bundle the power line, control line and communication cables together with or lay them
close to the main circuit, high-voltage line, load line or power line. As a guideline, lay the power
line, control line and communication cables at least 100 mm away from the main circuit, high-
voltage line, load line or power line.
- Ground the shield of the shielded wire or shielded cable at one point on the PLC. However, do not
use common grounding with heavy electrical systems.
- Ground the shield of the analog input/output cable at one point on the signal receiving side.
However, do not use common grounding with heavy electrical systems.
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or thicker.
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