Rockwell Automation 1747-L5xx SLC 500 Modular Hardware Style User Manual - Manual (Page 66)

Publication 1747-UM011G-EN-P - June 2008
66 System Installation Recommendations
Determining the Date of the SLC 500 Series A Chassis
The date of the chassis is found within the serial number imprinted on the
chassis nameplate on the right side of the chassis.
Master Control Relay A hard-wired master control relay (supplied by you) provides a convenient
means for emergency controller shutdown. Since the master control relay
allows the placement of several emergency-stop switches in different locations,
its installation is important from a safety standpoint. Overtravel limit switches
or mushroom head push buttons are wired in series so that when any of them
opens, the master control relay is de-energized. This removes power to input
and output device circuits.
Place the main power disconnect switch where operators and maintenance
personnel have quick and easy access to it. If you mount a disconnect switch
inside the controller enclosure, place the switch operating handle on the
outside of the enclosure, so that you can disconnect power without opening
the enclosure.
CAT
MADE IN U. S. A.
SLC 500
RACK
SER
UL
A 1746 - A7
SERIAL NO.
A7 -1195A1357
SA
® ®
Month
Year
Right Side
ATTENTION
Never alter these circuits to defeat their function, since serious
injury and/or machine damage could occur.
IMPORTANT
If you are using a dc power supply, interrupt the dc side rather
than the ac side to avoid the additional delay of power supply
turn-on and turn-off. The dc power supply should receive its
power directly from the fused secondary of the transformer.
Connect the power to the dc input and output circuits through a
set of master control relay contacts.