Mitsubishi Q80BD-J71GP21S-SX User Manual page 21

(2) Connection of power and ground cable
The power supply cable and ground cable for a personal computer
should be laid out as follows:
(a) Provide a grounding point near the power supply of personal
computer. Ground the FG (frame ground) terminal of the
personal computer and the SLD (shield) terminal of the CC-
Link IE Controller Network board with the thickest and shortest
grounding wire (wire for grounding) possible (about 30 cm
(11.81 in.) or less in length). Since the FG and SLD terminals
function to ground the noise generated in the personal
computer, it is necessary to ensure the lowest possible
impedance.
As the wires are used to relieve the noise, the wire itself
contains a large amount of noise and thus short wiring
prevents from functioning as an antenna.
(b) Twist the ground cable leading to the ground point with the
power supply cable. By twisting it with the ground cable, the
noise leaking from the power supply cable may be grounded at
a higher rate. However, twisting the power supply cable with
the ground cable may not be necessary if a noise filter is
installed on the power supply cable.
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