Rockwell Automation 1747-L40 SLC 500 Fixed Hardware Style - Manual (Page 42)

Chapter 2
System Installation Recommendations
2–3
In solid–state control systems, grounding helps limit the effects of noise due
to electromagnetic interference (EMI). The grounding path for the controller
and its enclosure is provided by the equipment grounding conductor.
Chassis
Mounting Tab
#10 AWG to
Ground Bus
Chassis Mounting Tab
Ground
Lug
Size 12 Internal
Star Washer
Tapped Hole
(Minimum of Three
Threads)
Metal Panel
(Must be connected to earth
ground.)
Scrape paint off panel to insure
electrical connection between chassis
and grounded metal panel.
Tapped Hole
(Minimum of Three
Threads)
Size 12 Internal
Star Washer
Scrape paint off panel to insure
electrical connection between chassis
and grounded metal panel.
Normal Electrical Noise Conditions Severe Electrical Noise Conditions
Metal Panel
(Must be connected to
earth ground.)
Size 10 or 12
Hardware Screw
Size 10 or 12
Hardware Screw
Size 12 Internal
Star Washer
!
ATTENTION: The SLC 500 controller, other control devices,
and the enclosure must be properly grounded. All applicable
codes and ordinances must be observed when wiring the
controller system.
Ground connections should run from the chassis and power supply on each
controller and expansion unit to the ground bus. Exact connections will
differ between applications. An authoritative source on grounding
requirements for most installations is the National Electrical Code. Also,
refer to Allen–Bradley Programmable Controller Grounding and Wiring
Guidelines, Publication Number 1770–4.1.
In addition to the grounding required for the controller and its enclosure, you
must also provide proper grounding for all controlled devices in your
application. Care must be taken to provide each device with an acceptable
grounding path.
Grounding Guidelines