Samsung SSA-S3020 ユーザーズマニュアル
16_
installation and external connection
installation and external connection
EARTH-GROUNDING THE COMMUNICATION CABLES
We recommend you to use a proper grounding system for the communication cables.
The best grounding method is to earth-ground the shield wire of the communication cable. However, earth-grounding the
communication cable isn’t that easy, apart from the cost increase.
communication cable isn’t that easy, apart from the cost increase.
There are three grounding points available for installation:
1. Earth Ground
2. Chassis Ground
3. Power Ground
The most important thing about the earth-grounding is not connecting both ends of the shield wire to the same grounding
system; Connecting both to the same end will cause a current fl ow through the shield wire due to the voltage level
difference between the both ends of the shield wire, and this current fl ow will introduce some noise and interference to
communications.
system; Connecting both to the same end will cause a current fl ow through the shield wire due to the voltage level
difference between the both ends of the shield wire, and this current fl ow will introduce some noise and interference to
communications.
We recommend you connect ONLY one end of the shield wire of the communication cable to the grounding system. If you
can locate an earth grounding point nearby, connect one end of the shield wire to that point.
can locate an earth grounding point nearby, connect one end of the shield wire to that point.
If you could hardly locate an earth grounding point nearby, connect one end of the shield wire to the chassis ground point.
If you could locate neither of an earth or chassis grounding point nearby, connect one end of the shield wire to the power
ground point (GND). Note that if the chassis is not properly earthed and fl oated from the ground level, then grounding
communication cable to the chassis will produce the worst communication. If this is the case, use the power grounding
point rather than the chassis grounding.
If you could locate neither of an earth or chassis grounding point nearby, connect one end of the shield wire to the power
ground point (GND). Note that if the chassis is not properly earthed and fl oated from the ground level, then grounding
communication cable to the chassis will produce the worst communication. If this is the case, use the power grounding
point rather than the chassis grounding.
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Earth Ground
or Chasis Ground
or Power Ground
HOST PC
RS-485/RS-232
Converter
Communication
Wires
Connect
ShieldWire
Open
GND
GND
GND
GND
RS-485
RS-485
RS-485
RS-232