Johnson Controls Penn System 450 Series Technical Bulletin page 38

IMPORTANT: Do not connect supply power to the System 450 modules
before checking all wiring connections. Short circuits or improperly connected
wires can result in damage to the modules and void any warranty.
IMPORTANT: A System 450 control module and module assembly can be
connected to an internal power source (a System 450 power module) or an
external power source (24 V power connected to the 24V and COM terminals on
the control module), but must not be connected to both power sources
simultaneously. Connecting a control module to both internal and external
power sources can damage the modules and void any warranty.
IMPORTANT: When connecting System 450 compatible sensors with
shielded cable to a System 450 control module, connect the cable shield drain
lead to one of the C (common) terminals on the input sensor terminal block. Do
not connect the shield at any other point along the cable. Isolate and insulate the
shield drain at the sensor end of the cable. Connecting a cable shield at more
than one point can enable transient currents to flow through the sensor cable
shield, which can cause erratic control operation.
Figure 15 and Figure 16 show the locations of and designations for the wiring
terminals for System 450 standard control modules and expansion modules.
System 450
Expansion Module
with Relay Output
(C450SCN-x)
Line-Voltage
Relay Output Terminals
(on Relay Control and
Expansion Modules)
Note: The C450xCN-x Control and Expansion module models have two output
relays and a second terminal block labeled LNC2, LNO2, and LC2.
Figure 15: Wiring Terminal Details for System 450 Control
and Expansion Modules with Relay Output
38 System 450™ Series Modular Control Systems with Standard Control Modules Technical Bulletin
Sn2
24V
C
C
Sn3
Sn1
5V
C
Common terminals (C)
are internally
connected.
Internal SPDT Relay
(Normally Closed Position)
System 450
Control Module
with Relay Output
(C450CCN-x)