24 Rockwell Automation Publication 1766-UM001O-EN-P - September 2021
Chapter 2 Install Your Controller
• In the following illustration, input and output circuits are shown with
MCR protection. However, in most applications, only output circuits
require MCR protection.
Figure 3
and Figure 4 show the Master Control Relay wired in a grounded
system.
Figure 3 - Schematic (Using IEC Symbols)
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.
Disconnect
Isolation
Transformer
Emergency-Stop Push
Button
Fuse MCR
230V AC
I/O Circuits
Operation of either of these contacts will remove
power from the external I/O circuits, stopping
machine motion.
Fuse
Overtravel
Limit Switch
MCR
MCR
MCR
Stop Start
Line Terminals: Connect to terminals of Power Supply
(1766-L32AWA, 1766-L32AWAA, 1766-L32BWA, 1766-L32BWAA).
115V AC or
230V AC
I/O Circuits
L1
L2
230V AC
Master Control Relay (MCR)
Catalog Number 700-PK400A1
Suppressor
Catalog Number 700-N24
MCR
Suppr.
24V DC
I/O Circuits
(Lo)
(Hi)
DC Power Supply.
Use IEC 950/EN 60950
X1 X2
115V AC
or 230V AC
Line Terminals: Connect to 24V DC terminals of Power Supply
(1766-L32BXB, 1766-L32BXBA)
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