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14. EMC AND LOW VOLTAGE DIRECTIVES
14.1.2 Installation instructions for EMC directive
(1) Installation
Installing inside a control panel not only ensures safety but also ensures effective shielding of position
board-generated electromagnetic noise.
(a) Control panel
1) Use a conductive control panel.
2) When attaching the control panel's top plate or base plate, expose bare metal surface and weld so
that good surface contact can be made between the panel and plate.
3) To ensure good electrical contact with the control panel, mask the paint on the installation bolts of the
inner plate in the control panel so that contact between surfaces can be ensured over the widest
possible area.
4) Ground the control panel with a thick wire so that a low impedance connection to ground can be
ensured even at high frequencies.
5) Holes made in the control panel must be 10cm (3.94inch) diameter or less. If the holes are 10cm
(3.94 inch) or larger, radio frequency noise may be emitted. In addition, because radio waves leak
through a clearance between the control panel door and the main unit, reduce the clearance as much
as practicable. The leakage of radio waves can be suppressed by the direct application of an EMI
gasket on the paint surface.
(2) Connection of power line and ground wire
Ground wire and power supply cable for the host controller must be connected as described below.
(a) Provide a grounding point near the FG terminal. Ground the FG terminals (Frame Ground) with the
thickest and shortest wire possible. (The wire length must be 30cm (11.81inch) or shorter.) The FG
terminals function is to pass the noise generated in the position board to the ground, so the ground wire
ensures a low impedance as possible.
Because the wire does the role to transfer the noise, the wire itself carries a large noise content and thus
short wiring means that the wire is prevented from acting as an antenna.
(b) Twist the ground wire drawn out from grounding point with the power line. By twisting the power line with
ground wire, it can transfer the noise more from power line to the ground. However, if the noise filter is
attached to the power line, it might be unnecessary to twist with the ground wire.
(3) Forced stop input cable
The forced stop input cable length must be within 30m (98.43ft.).