Rockwell Automation 1747-L40 SLC 500 Fixed Hardware Style - Manual (Page 47)

Chapter 2
System Installation Recommendations
2–8
Safety considerations are an important element of proper system installation.
Actively thinking about the safety of yourself and others, as well as the
condition of your equipment, is of primary importance. Several safety areas
are discussed below.
High Voltages -
SLC 500 Fixed Hardware Style Controller (Series C)
(Applies to 1747-L20A, -L30A, -L40A, -L20C, -L30C, and -L40C
controllers)
Front Cover
!
ATTENTION: The printed circuit board, located under the front
cover of Series C Fixed Hardware Style Controllers, has high
voltages (120 VAC and 240 VAC) available at certain points
when the controller is powered up. If the front cover is removed,
exercise extreme care and consider all points on the circuit board
to be electrically hazardous. Therefore, whenever possible, turn
off power to the controller before removing the front cover. Do
not remove the protective insulation covering the circuit board.
Cutouts in the insulation are provided to allow access to the
high–speed counter jumper, memory module, and battery
connector. If the insulation is missing, do not touch any portion
of the circuit board. Failure to heed this warning may result in
personal injury or death.
Disconnecting Main Power
The main power disconnect switch should be located where operators and
maintenance personnel have quick and easy access to it. Ideally, the
disconnect switch is mounted on the outside of the enclosure, so that it can
be accessed without opening the enclosure. In addition to disconnecting
electrical power, all other sources of power (pneumatic and hydraulic) should
be de–energized before working on a machine or process controlled by an
SLC controller.
Safety Considerations