VX121P/151P/171P(-QM57)
User’s manual rev.0.0 (Preliminary)
MU-C656.xxxxxxxxxx r.0.0-EN
31 of 68
5.6 Equipotential bonding
Low impedance connections toward earth reduce the interference current from
external power supply cables, signal cables and peripheral connection cables.
The Panel PC equipotential bonding is located near the input terminal of the
power supply.
Between different parts of an electric plant it makes electrical potential that, in
some cases, can generate high equalization currents. It occurs for example when
both sides of the shield of a cable are grounded at different point of the plant.
Potential differences can be for example different power supply.
If necessary is possible to reduce the potential difference by laying the
equipotential bonding cable as the electronic devices function properly.
For the equipotential bonding see as follow:
•
If two system parts are connected trough shielded cable and their shields
are connected both sides to ground or protection conductor, the following
must be observed: the impedance of the equipotential bonding cable should
be having an impedance max. of 10% of the shield impedance.
•
The section of the equipotential bonding cable has to be sized for the
maximum compensation current present. The cross-section in any case
should be not less than 5mm
2
and bigger size is better.
•
Use equipotential bonding cables made of copper or galvanized steel.
Connect the cables to ground over a wide area. Protect the ground or the
protective conductor against the corrosion.
•
The surface area between the signals cable and the equipotential bonding
cable should be as small as possible.
5.7 Connecting external keyboard/mouse
Two PS/2 style connectors allow the connection of an external keyboard and
mouse. These connectors are on the I/O panel. The mouse connector is green
while the keyboard one is violet.
Notice
If commercial PS/2 peripheral are used, the EMC immunity often is
suitable for office use only. For the start up and for the assistance
these devices are enough.
Moreover for industrial use of industry-standard devices are
recommended. Furthermore proper EMC practice must be considered
in cabling the external keyboard or mouse.
Caution
Do not connect or disconnect the external keyboard or mouse when
the Panel PC is switched on. Switch off input power before
connecting or disconnecting the keyboard or the mouse.