Chapter 3 Installation Guidelines
Manual VIPA HMI
3-10
HB160E - TP - RE_610-3B2J0 - Rev. 09/09
In exceptional cases it may be necessary to ground the screen on one side
only. However, this will only attenuate the lowest frequencies. The one-
sided grounding of screens may provide advantages when:
•
It is not possible to install an equipotential bonding conductor
•
Analogue signals (a few mV or
µ
A) must be transmitted
•
Foil-type screening (static screening) is employed.
You should always use metallic or metallic covers for serial data lines.
Connect the screen of the data line to the cover. Do
not
connect the
screen to PIN 1 of the connector!
In case of stationary operations it is recommended that the remove the
insulation from the screened cable without cutting the screen and to attach
this point to the screening/neutral rail.
Note!
Potential differences can give rise to an equalization current via the screen
connected between the two ground connections.
In this case you must install an additional equipotential bonding conductor.
Please observe the following points when you handle the screens:
•
Use only metallic cable clamps when connecting the screening of
cables. These clamps must provide a good electrical contact and a
large-surface connection to the screen.
•
Attach the screens to the screening rail directly at the point where the
cables enter the enclosure.
The screening conductor must be continued to the module without
interruption, however, it must not be connected to the module!
One-sided
grounding of
screens
Connecting the
screen
