Mitsubishi MELSEC L Series User Manual page 388

(3) Cables
Use a shielded cable for the cable connected to the I/O module 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 required value.
(a) Grounding a shielded cable
• Ground the shield of a 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 to large area on the control panel. A clamp fitting can be used as shown below.
In this case, mask off the inner wall surface of the control panel, where comes in contact with the fitting.
Grounding with a vinyl-coated wire soldered onto the shield 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.
386
Screw
Paint mask
Shielded cable
PVC wire
Solderless terminal
Clamp fitting
Shielded cable