Mitsubishi Electric MR-MQ100 User Manual page 249

15 EMC DIRECTIVES
(3) Cables
The cables extracted from the control panel contain a high frequency noise
component. On the outside of the control panel, therefore, they serve as
antennas to emit noise. To prevent noise emission, use shielded cables for the
cables and may be extracted to the outside of the control panel.
The use of a shielded cable also increases noise resistance.
If a shielded cable is not used or not grounded correctly, the noise resistance will
not meet the specified requirements.
(a) Grounding of shield section of shield cable
1) Ground the exposed shield section of the shielded cable close to the
module. When the grounded cables and the not yet grounded cables
are bundled, the cables might be induced to electromagnetic.
2) Ground the exposed shield section to spacious area on the control
panel. A clamp can be used as shown in Figure 15.2.
In this case, mask the inner wall surface when coating the control panel,
and contact the exposed shield section with the clamp at the exposed
bare metal surface.
Shield section
Figure 15.1 Part to be exposed
Note) The method of grounding with a vinyl-coated wire soldered onto
the shielded section of the shielded cable as in shown Figure
15.3 is not recommended. Doing so will raise the high-frequency
impedance, resulting in loss of the shielding effect.
Figure 15.3 Shield grounding (Incorrect example)
(4) Precautions for static electricity
There are weak points to static electricity on a surface of modules. Before
touching the modules, always touch grounded metal, etc. to discharge static
electricity from human body. Failure to do so may cause the modules to fail or
malfunction. And do not directly touch the module's conductive parts and
electronic components. Touching them could cause an operation failure or give
damage to the module.
Exposed bare
metal surface
Figure 15.2 Shield grounding (Correct example)
Shield cable
Wire
Solderless terminal, crimp contact
15 - 4
Screw
Clamp fitting
Shield cable