Rockwell Automation System Design for the Control of Electrical Noise - Manual (Page 23)

Publication GMC-RM001A-EN-P — July 2001
High Frequency (HF) Bonding 2-5
Extending the Ground Plane Principle
The same theory holds true regardless of scale, (the earth being the
ultimate and literal ground plane) and can be used at control cabinet
level or even building level, but requires rigorous implementation.
A ground plane does not have to be flat, but gentle curves prove more
effective than sharp corners. Area is what matters. Even the outer
surface of a machine structure can be used.
Grounding a PCB to the Drive Chassis
In the figure below, a PCB ground plane is extended by bonding it to
the drive chassis.
Figure 2.4
PCB ground plane extended to the drive chassis
Guidelines for the system builder include:
• When permitted, the control circuit common should be grounded.
• Some products do not permit grounding of the control common,
but may allow grounding to chassis via a 1.0
µ
F, 50V ceramic
capacitor. Check your installation manual for details.
PCB copper
ground plane layer
bonded to drive chassis
PCB copper
interconnection
layer
Drive
chassis
Printed circuit
board (PCB)