Rockwell Automation 8520 9/Series CNC Integration Maintenance Manual Documentation Set - Manual (Page 428)

Section 7C
Power Distribution and Wiring Guidelines
7C-10
The following sections explain different types of noise and measures to
reduce them.
Electrical Noise
Electrical noise can be considered to be unwanted electrical signals, which
produce undesirable effects in the circuits of the control systems in which
they occur. High intensity noise can interfere with system functioning.
The following sections explain electrical noise and the measures to reduce
them.
Electrical noise is transmitted in two ways. One means of transmission is
through cables (conducted noise). The other is transmission through the
air (radiated noise).
Figure 7C.12
Noise Transmission Routes
Radiated noise
Conducted noise
Wire or cable
Source Destination
11233-I
Conducted Noise
Conducted noise is transmitted to the control through conductors such as
power source cables, signal cables, and grounding cables. Conducted
noise is further divided into two modes; normal mode and common mode.
As shown in Figure 7C.13, normal mode noise reaches the control by
passing through the two lines. Common mode noise reaches the control by
passing through each line and the conductor that functions as the common
potential for the two lines.
7C.2
Reducing Noise