Grounding Of Process Signals - ABB Advant Controller 450 User Manual

2.2.5.7 Grounding of Process Signals

3BSE 002 415R701 Rev A
CE-marked Design
A EMC-proof cabinet must be used for the I/O subrack and the connection units as well.
The cable shield shall be grounded in both ends according to
Not CE-marked Design
The description given under the heading General is adequate. The cable is mechanically
anchored to the horizontal mounting bar close to the bottom of the cabinet. Leave the cable
unstripped.
There are three applications of signal grounding directly to the chassis. (High-frequency
grounding by capacitors is always provided and not discussed in this context.)
1. Signals are automatically grounded to the chassis by the connection unit. This quality is
determined by the selection of I/O unit or connection unit. Some board types require
grounded signals while others can be applied to non-grounded signals (and grounded).
Please see the connection unit documentation on a case-by-case basis.
2. Signals can be commonly grounded by grounding the reference 0V of centralized power
supply for loads and sensing. Such a power supply system must be grounded to the same
earth line as the Advant OCS.
If the power supply unit is placed in the controller or I/O cabinet, 0V is grounded to the
protective earth screw.
Local grounding of loads and sensors is then impossible!
3. Individual grounding of a signal in the controller cabinet is possible (if it is applicable with
respect to board type and connection unit type selected).
The 0 V signal connection at the connection unit is reconnected and grounded to the
mounting rail. Lead length is not critical.
Use a self-tapping screw. See
Such an application requires that the signal not be grounded otherwise, for example, not
locally grounded at load/sensor or not grounded via a power supply grounding.
Advant
Figure 2-13.
®
Controller 450 User's Guide
Section 2.2.5 Grounding
Figure 2-12.
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