Rockwell Automation 1762-Lxxxxx MicroLogix 1200 Programmable Controllers Installation Instructions - Manual (Page 20)

20 MicroLogix 1200 Programmable Controllers
Publication 1762-IN006C-EN-P - September 2009
Grounding the Controller
In solid-state control systems, grounding and wire routing helps limit the effects of noise due
to electromagnetic interference (EMI). Run the ground connection from the ground screw of
the controller to the ground bus prior to connecting any devices. Use AWG #14 wire. For
AC-powered controllers, this connection must be made for safety purposes.
You must also provide an acceptable grounding path for each device in your application. For
more information on proper grounding guidelines, refer to the Industrial Automation Wiring and
Grounding Guidelines, publication 1770-4.1.
ATTENTION
All devices connected to the RS-232 channel must be
referenced to controller ground, or be floating (not referenced
to a potential other than ground). Failure to follow this
procedure may result in property damage or personal injury.
• For 1762-L24BWA, 1762-L40BWA, 1762-L24BWAR and
1762-L40BWAR controllers:
The COM of the sensor supply is also connected to chassis
ground internally. The 24V dc sensor power source
should not be used to power output circuits. It should
only be used to power input devices.
• For 1762-L24BXB, 1762-L40BXB, 1762-L24BXBR and
1762-L40BXBR controllers:
The VDC NEUT or common terminal of the power supply
is also connected to chassis ground internally.