Rockwell Automation 1764-xxxx MICROLOGIX 1500 PROGRAMMABLE CONTROLLERS - Manual (Page 35)

Publication 1764-UM001B-EN-P - April 2002
Installing Your Controller 2-9
equipment within the enclosure, use the disconnect to shut off power
to the rest of the system.
Using Emergency-Stop Switches
When using emergency-stop switches, adhere to the following points:
•
Do not program emergency-stop switches in the controller
program. Any emergency-stop switch should turn off all
machine power by turning off the master control relay.
•
Observe all applicable local codes concerning the placement
and labeling of emergency-stop switches.
•
Install emergency-stop switches and the master control relay in
your system. Make certain that relay contacts have a sufficient
rating for your application. Emergency-stop switches must be
easy to reach.
•
In the following illustration, input and output circuits are shown
with MCR protection. However, in most applications, only
output circuits require MCR protection.
The following illustrations show the Master Control Relay wired in a
grounded system.
TIP
Do not control the master control relay with the
controller. Provide the operator with the safety of a
direct connection between an emergency-stop switch
and the master control relay.
TIP
In most applications input circuits do not require
MCR protection; however, if you need to remove
power from all field devices, you must include MCR
contacts in series with input power wiring.