Mitsubishi Electric LCPU-U-HW Safety Manuallines page 48

(2) Installation in a control panel
The programmable controllers are open type devices and must be
installed inside a control panel.
This ensures safety as well as effective shielding of programmable
controller-generated electromagnetic noise.
*1 Modules on the remote station in each network must be also installed inside the control
panel. However, the waterproof type remote station can be installed outside the control
panel.
(a) Control panel
(b) Wiring power cables
• Use a conductive control panel.
• When securing the top or bottom plate using bolts, cover the
grounding part on the control panel so that the part will not
be painted.
• To ensure electrical contact between the inner plate and
control panel, take measures such as covering the bolts so
that conductivity can be ensured in the largest possible
area.
• Ground the control panel with a thick ground cable so that
low impedance can be ensured even at high frequencies.
• Holes in the control panel must be 10cm diameter or less. If
the holes are larger than 10cm, radio wave may be emitted.
In addition, because radio waves leak through a clearance
between the control panel and its door, reduce the clearance
as much as possible. The leakage of radio waves can be
suppressed by the direct application of an EMI gasket on the
paint surface.
Our tests have been carried out on a panel having the
attenuation characteristics of 37 dB (max.) and 30 dB (mean)
(measured by 3m method, 30 to 300MHz).
• 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.
*1
47