Allen-Bradley 2080-LC20-20QWB User Manual page 28

Chapter 2 About Your Controller
20
• 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.
In most applications input circuits do not require MCR protection;
TIP
however, if you need to remove power from all field devices, you must
include MCR contacts in series with input power wiring.
Rockwell Automation Publication 2080-UM005B-EN-E - March 2015