Advantech TPC-300 Series, Руководство пользователя

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TPC-300 Series/TPC-B510 User Manual 20
2.5 Power/Digital Ground and Earth/Ground
The power/digital ground blocks external electrical interference to the chassis,
thereby ensuring that bad grounding does not cause electric shocks. This is known
as Level 1 isolation, which is not typically implemented in consumer-grade devices.

TPC chassis and ground (Power Pin 3) are short.

TPC chassis and power/digital ground are open.
Figure 2.9 TPC Chassis and Power Supply
The TPC devices are industrial-grade products. The hardware is designed to protect
against external interference and eliminate the risk of electric shock. To ensure isola -
tion protection, the following must be considered:

The Ethernet connection is isolated. LAN connections will not affect the isolation
design.

General USB devices are built to minimize EMI and ESD issues, such as a
chassis or digital short. The TPC devices block EMI and ESD, protecting USB
devices from damage. The devices are designed to use Power GND as a vent
path to ensure Power GND and Chassis GND do not differ abnormally.

For various COM port designs, long-distance connections can cause voltage dif -
ferences between the two COM port chassis. Therefore, the shell ground of the
cable must be isolated to the signal digital ground.
Use of a third-party device or cable can disrupt Level 1 isolation. In such circum -
stances, users should short all grounds (Power GND/Digital GND/Earth GND) and
ensure adequate earth/ground connection.