9LOADING AND INSTALLATION

(2)Wiring of I/O equipment

MELSEC-Q

(a)Insulation-sleeved crimping terminals cannot be used with the terminal block. It is recommended to cover the wire connections of the crimping terminals with mark or insulation tubes.

(b)The wires used for connection to the terminal block should be 0.3 to 0.75mm2 in core and 2.8mm (0.11 inch) max. in outside diameter.

(c)Run the input and output lines away from each other.

(d)When the wiring cannot be run away from the main circuit and power lines, use a batch-shielded cable and ground it on the PLC side.

In some cases, ground it in the opposite side.

PLC

Shielded cable

 

Input

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RA

OutputShield

DC

(e)Where wiring runs through piping, ground the piping without fail.

(f)Run the 24VDC input line away from the 100VAC and 200VAC lines.

(g)Wiring of 200m (686.67 ft.) or longer distance will give rise to leakage currents due to the line capacity, resulting in a fault.

Refer to Section 11.5 for details.

(3) Grounding

To ground the cable, follow the steps (a) to (c) shown below.

(a)Use the dedicated grounding as far as possible.

(b)When a dedicated grounding cannot be performed, use (2) Common Grounding shown below.

PLC

Another

PLC

 

 

Another

PLC

Another

equipment

 

 

equipment

equipment

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

grounding

 

 

grounding

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(1) Independent grounding.....

Best (2) Common grounding Good.....

.....(3) Joint grounding Not allowed

(c)For grounding a cable, use the cable of 2 mm2 or more.

Position the ground-contact point as closely to the sequencer as possible, and reduce the length of the grounding cable as much as possible.

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