Rockwell Automation 1761-HHP-B30 MicroLogix 1000 with Hand-Held Programmer (HHP) - Manual (Page 20)

Chapter 1
Installing Your Controller
1–4
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.
Important: The illustrations only show output circuits with MCR
protection. 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.