Mitsubishi Electric MELSEC-L SSCNETIII/H User Manual page 128

(b) Wiring of power cables and ground cables
• Provide a ground point near the power supply module. Ground the LG and FG terminals of the power supply
module with the thickest and shortest ground cable (30cm or shorter) possible.
(3) Cables used for the modules connected to the head module
Use shielded cables for the cables which are connected to the I/O modules and may be extended out of the
control panel.
If a shielded cable is not used or not grounded correctly, the noise immunity will not meet the specified value.
(a) Grounding the shield of the shielded cable
• Ground the shield of the shielded cable as close to the module as possible so that the grounded cable will
not be affected by electromagnetic induction from ungrounded cables.
• Ground the exposed shield section to large area on the control panel. A clamp fitting can be used as shown
in below. In this case, apply a cover on the painted inner wall surface of the control panel, which comes in
contact with the fitting, so that the surface is not painted.
• Grounding with a vinyl-coated wire soldered onto the shielded section of the shielded cable as shown below is not
recommended. Doing so will raise the high-frequency impedance, resulting in loss of the shielding effect.
126
Screw
Paint mask
Shielded cable
Vinyl-coated wire
Solderless terminal
Clamp fitting
Shielded cable