Rockwell Automation 1761 MicroLogix 1000 Programmable Controllers - Manual (Page 36)

Preface MicroLogix 1000 Programmable Controllers User Manual
2–2
Grounding Guidelines
In solid-state control systems, grounding helps limit the effects of noise due to
electromagnetic interference (EMI). Use the heaviest wire gauge listed for wiring
your controller with a maximum length of 152.4 mm (6 in.). Run the ground
connection from the ground screw of the controller (third screw from left on output
terminal rung) to the ground bus.
Note This symbol denotes a functional earth ground terminal which provides a low
impedance path between electrical circuits and earth for non-safety purposes, such
as noise immunity improvement.
Protective
Wrap (remove after wiring)
All devices that connect to the user 24V power supply or to the RS-232 channel
must be referenced to chassis ground or floating. Failure to follow this
procedure may result in property damage or personal injury.
Chassis ground, user 24V ground, and RS-232 ground are internally
connected. You must connect the chassis ground terminal screw to chassis
ground prior to connecting any devices.
On the 1761-L10BWB, 1761-L16BWB, 1761-L16BBB, 1761-L20BWB-5A,
1761-L32BBB, and 1761-L32BWB controllers, the user supply 24 V dc IN and
chassis ground are internally connected.
You must also provide an acceptable grounding path for each device in your
application. For more information on proper grounding guidelines, see the
Industrial Automation Wiring and Grounding Guidelines publication 1770-4.1.
Remove the protective wrap before applying power to the controller. Failure
to remove the wrap may cause the controller to overheat.