Rockwell Automation 2755-DM9, -DM9E High Speed Decoder - Manual (Page 76)

Chapter 5
Installing the Decoder
5–2
!
WARNING: Do not remove the housing of the decoder. No user
maintenance of the decoder is required. An access panel is
provided for installation and wiring of output modules.
Install this equipment using publication NFPA 70E, Electrical Safety
Requirements for Employee Workplaces. We have set up a few specific
guidelines for you to follow in addition to the general guidelines of NFPA
70E.
Before connecting the decoder to the incoming power, verify that the source
power is 85 to 264 volts AC, 47 to 63 Hz.
Careful wire routing helps to cut down on electrical noise. To reduce
electrical noise, the decoder should be connected to its own branch circuit.
The input power must be externally protected by a fuse or circuit breaker
rated at no more than 15 amps. Route incoming power to the Decoder by a
separate path from the communication cables. Do not run signal wiring
and power wiring in the same conduit! Where paths must cross, their
intersection should be perpendicular.
With solid-state systems, grounding helps to limit the effects of noise due to
electromagnetic interference (EMI). To avoid problems caused by EMI,
shielded cables should be used.
The recommendations given above will provide favorable operating
conditions for most installations.
When the decoder is operating in a noise-polluted industrial environment,
special consideration should be given to possible electrical interference. The
effect of electrical interference has been minimized by the basic design of the
hardware. Properly grounding the equipment, correctly routing wires and the
use of shielded cables will also help minimize interference.
Grounding is an important safety measure in electricalinstallations. With
solid-state systems, grounding also helps limit the effects of noise due to
electromagnetic interference (EMI).
An authoritative source on grounding requirements is the National Electrical
Code published by the National Fire Protection Association of Boston,
Massachusetts. Article 250 of the Code discusses the types and sizes of wire
conductors and safe methods of grounding electrical equipment and
components.
Electrical Precautions
How to Handle Excessive Noise
Grounding Recommendations