Ferrite Core; Noise Filter (Power Line Filter) - Mitsubishi A-Melsec A1FXCPU User Manual

5. EMC DIRECTIVE, LOW VOLTAGE DIRECTIVE

5.1.4 Ferrite core

5.1.5 Noise filter (Power line filter)

(2) I/O signal lines and other communication cables
For I/O signal lines and other communication cables (RS-232C, RS-422, etc.)
drawn to outside the control box, their shields must also be grounded as
described in (1).
A ferrite core has an effect on noise reduction in the 30MHz to 100MHz bandwidth of
radiation noise. With the exception of some models, ferrite cores are not required to
be fitted to cables. However, if the shields of shielded cables drawn to outside the
control box do not produce sufficient effects, it is recommended to fit ferrite cores.
The ferrite cores we used in our tests are TDK's ZCAT3035.*
Ferrite cores should be fitted immediately before cables are drawn to outside the
control box. If ferrite cores are not fitted in proper position, they will lose their effects.
*: To ensure the compliance with CE (EN6111-21/A11), make sure to short the LG
and FG terminals using a wire of 6 to 7cm.
A noise filter has an effect on conduction noise. With the exception of some models,
a noise filter is not required to be fitted to the power line, but fitting it can further
suppress noise. (A noise filter is effective on noise reduction in the 10MHz or less
bandwidth of conduction noise.) Use any of the following noise filters (double π type
filters) or equivalent:
Type FN343-3/01
Maker SCHAFFNER
Rated current
Rated voltage
The instructions below should be followed when fitting a noise filter.
(1) Do not bundle the input and output side wirings of the noise filter. Doing so will
induce output side noise into the input side wiring whose noise has been
removed by the filter.
Filter
(a) Noise will be induced if input and
output wirings are bundled
(2) Connect the ground terminal of the noise filter to the control box in the shortest
possible distance (about 10cm).
FN660-6-06
SCHAFFNER
3A 6A
250V
Input side Input side
(Power supply side) (Power supply side)
Induction
Output side
(Equipment side)
5 - 5
ZHC2203-11
TDK
3A
Filter
(b) Route input wiring away from
output wiring.
MELSEC-A
Induction
Output side
(Equipment side)