Power Supply Module; Others - Mitsubishi Electric QS001CPU User Manual

9
EMC, LOW VOLTAGE, AND MACHINERY DIRECTIVES

9.1.4 Power Supply Module

Always ground the LG and FG terminals after short-circuiting them.

9.1.5 Others

(1) Ferrite core
9
- 7 9.1 Requirements for Conformance to EMC Directive
9.1.4 Power Supply Module
A ferrite core has the effect of reducing conduction noise in around 10MHz band and
radiated noise in the 30MHz to 100MHz band.
It is recommended to fit ferrite cores if shielded cables pulled out of the panel do not
provide sufficient shielding effects or if the emission of conduction noise from the
power supply line has to be suppressed.
It is also recommended to fit a ferrite core to the USB cable which connects the CPU
and the personal computer as measures against noise.
Regarding the number of winding to the ferrite core, the more the better. The two turns
or more is recommended as the number of winding.
Figure 9.10 For number of winding is two turns or more
Note that the ferrite cores should be fitted to the cables in the position immediately
before they are pulled out of the panel. If the fitting position is improper, the ferrite will
not produce any effect.