Penn System 450 User Manual

System 450 Series Modular Controls Product

Bulletin

LIT-12011458

2021-07-21

Introduction

The System 450™ is a family of modular, digital electronic
controls that you can assemble and set up to provide
reliable temperature, pressure, and humidity control for a
wide variety of HVAC, commercial, and industrial process
applications.

The System 450 control system replaces the System
350™ and System 27 control systems, and provides
additional features and benefits with fewer than 20 model
variations. The System 450 control modules provide a
field-configurable out-of-the-box solution. Most System
450 control modules can control temperature, pressure,
and humidity systems simultaneously.

You can set up a single C450 control module as a stand­alone control or to connect with expansion modules to
control up to 10 On/Off relay and proportional analog
outputs, based on any of the three available inputs.

Use the System 450 control modules with communications
to connect System 450 control systems to Modbus® or
Ethernet networks for remote monitoring and setup. The
Modbus communications control module is an RS485,
rooftop unit (RTU) compliant subordinate device. The
Ethernet communications control module has an integral
web server that can deliver web pages through a direct
connection, on your LAN, or across the internet.

The System 450 reset control modules provide many of
the features of the standard models for temperature
and humidity control. In addition, these modules provide
setpoint reset, real-time setback scheduling, and equal
run-time balancing capability.

The System 450 control module with hybrid analog output
has a single self-selecting analog output to optimize and
extend the controlled speed range of variable speed
electronically commutated (EC) motors.

Figure 1: System 450 Control System with control,
power, and expansion modules

Features and benefits

Durable, compact, interchangeable modular
components with plug-together connectors and DIN
rail or direct wall mount capability

Eliminate field wiring between modules and quickly and
easily design, assemble, install, and upgrade your control
systems.

Versatile, multipurpose, field-configurable control
modules and expansion modules designed for global
use

Create a wide variety of application-specific control
systems to control temperature, pressure, or humidity, or
all three conditions simultaneously, with only a small suite
of module models.

Control modules with bright backlit LCDs and four­button touchpad UIs, up to three hard-wired input
sensors, and up to 10 relay or analog outputs in any
combination for each control system

Provide a quick, clear, visual status of your System 450
control system inputs and outputs with the touch of a
button and quickly and easily set up and adjust your
control system.

Extensive suite of compatible temperature and
humidity sensors and pressure transducers

Monitor and control a wide range of HVAC and process
conditions in a variety of standard and global units of
measurement.

Differential control

Enables your control system to monitor and maintain a
temperature, pressure, or humidity differential between
two sensor points within a system, process, or space.

On/Off delays

Configure an on delay and an off delay to set the times
between a setpoint trip and the energizing or de­energizing of a relay.

C450Cxx, C450Rxx, C450Sxx, C450Yxx

Overview

The System 450 Series is a family of compact digital
electronic control, expansion, and power modules that
you can assemble and set up to provide reliable on/
off and proportional control of temperature, pressure,
and humidity conditions in a wide variety of HVAC,
commercial, and industrial process applications.

A System 450 Series control system includes the following
features:

• A single control module with LCD and 4-button
touchpad

• One to three inputs

• One to 10 relay or analog outputs provided by the
control module and expansion modules

• An optional power module

Compact modular plug-together design

All System 450 modules feature a compact, durable,
gray LEXAN® housing with DIN rail clips and slotted
mounting holes molded into the back of the housing for
easy installation.

The System 450 modules also feature 6-pin connectors on
the sides of the housing for easy assembly, upgrade of
your control systems, and to eliminate the need for field
wiring between modules.

A System 450 control system provides compact, clean, and
consistent control system assemblies that are simple to
build, install, and maintain.

Multipurpose and field-configurable design

The System 450 control, expansion, and power modules
are multipurpose devices that you can configure in the
field to control temperature, pressure, and humidity
simultaneously.

On/Off relay control

Relay outputs provide low and line-voltage on/off control
for devices and equipment in the controlled systems.
Each relay is a single-pole, double-throw (SPDT) set of dry
contacts.

Note: The System 450 output relays are SPDT dry
contact relays only and do not provide any power
source for the controlled equipment.

See Technical Specifications for output relay electrical
rating information. See Table 1 for information on the
System 450 control modules with this feature.

Analog proportional control

Analog outputs provide proportional analog signals for
devices and equipment in your controlled systems.

Each analog output can generate either a 4 mA to 20
mA or 0 VDC to 10 VDC signal. The output signal type is
self-selecting; after you connect the analog output to
the controlled equipment, the output detects the analog
input on the controlled equipment and generates the
appropriate analog signal for the connected input.

You can set up an analog output to generate a direct
acting or reverse acting proportional output signal. You
can also set up the output signal strength to increase
or decrease in either the direct acting or reverse acting
mode. See the example in Figure 4.

An analog output’s control action is automatically
determined by the setup values you select for the
setpoint, end point, % output at setpoint, and % output at
endpoint values when you set up the output in the UI.

A control ramp indicator appears on the output status
screen for each analog output to represent the analog
output’s control action.

Figure 2: Proportional analog output operation for
reverse acting room heating application

Global design

A System 450 control system is the next generation of
System 350 and System 27 modular controls.

The System 450 modular control system has fewer than
20 model variations and provides far more features and
flexibility than either the System 350 modular control
system with 54 models, or the System 27 modular control
system with 40 models.

The System 450 modules are designed, tested, and
certified for global application and are Underwriters’
Laboratories, Inc. (cULus) Listed and CE compliant.

You can set up the System 450 control systems in the
global standard units of measurement such as Fahrenheit,
Celsius, psi, bar, inches water column (in. W.C.), and
relative humidity (RH).

Control capabilities

The System 450 control system provides a variety of
control capabilities depending on the model you select.
See Table 1 for information on System 450 control
modules with specific features.

System 450 Series Modular Controls Product Bulletin2

See Table 1 for information on the System 450 control
modules with this feature.

Proportional plus integral control

In addition to standard proportional only control analog
signals, a System 450 control system provides integral

control capability and six time integral selections that
you can use to set up analog outputs to generate a
proportional plus integral signal.

Proportional plus integral (PI) control incorporates a
time-integral control action with proportional control
action. If correctly set up, a PI control loop can effectively
eliminate offset error and enable a controlled system to
drive much closer to the preferred setpoint, even under
large constant loads. On a properly sized system with
predictable loads, PI control can maintain the controlled
system very close to the setpoint.

The integration constant that you select establishes the
rate at which the control readjusts the analog output
signal. The faster the integration constant, the faster the
control readjusts the output signal, and the faster the
recovery rate of a properly sized and setup control loop.
See Table 1 for information on the System 450 control
modules with this feature.

Multistage On/Off and proportional control

You can set up multiple outputs to create a variety of
equipment staging control systems. Depending on the
control module and expansion modules, a System 450
multistage application may use On/Off control relay
outputs or proportional control analog outputs. See Table
1 for information on the System 450 control modules with
this feature.

High input signal select

The High Input Signal Selection feature enables a System
450 control system to monitor a temperature, pressure, or
humidity condition with two or three sensors of the same
type and control relay and analog outputs based on the
highest condition value sensed.

See Table 1 for information on the System 450 control
modules with this feature.

Differential control

The Differential Control feature enables a System 450
control system to monitor and maintain a temperature,
pressure, or humidity differential between two sensors
of the same type. This feature also enables the control
system to control relay outputs, analog outputs, or a
combination of relay and analog outputs, based on
the sensed differential value relative to user-selected
differential values. An example is the water pressure drop
across an in-line water filter. See Table 1 for information
on the System 450 control modules with this feature.

Reset control

The System 450 reset control modules automatically
adjust the setpoint for a supply control loop, based on
input from the outdoor or ambient master sensor and the
user-selected reset setpoint settings. This functions saves
energy by using only the required capacity of the supply
to heat, cool, dehumidify, or humidify the preferred space
or environment.

See Figure 3 for an example of Setpoint Reset Control for
both a chilled water temperature reset application and a
boiler water temperature reset application. See Table 1 for
information on the System 450 control modules with this
feature.

Figure 3: Reset setpoint application for boiler water
supply (BWS) and chiller water supply (CWS) showing
relationships between the reset

Setback scheduling

Use the reset control module’s real-time clock to schedule
outputs by day of week and time of day.

You can also set up setback temperatures and humidity
to create an occupied or unoccupied setback schedule
for the outputs in your control system. You can select a
negative setback value for heating or humidification, or
a positive setback value for cooling or dehumidification
control. See Table 1 for information on the System 450
control modules with this feature.

Run-time balancing

The reset control module’s run-time balancing feature
enables your control system to even out the runtimes of
staged equipment by automatically selecting the stage
with the smallest runtime when it responds to increases in
the system load.

Use run-time balancing to control up to four staged
outputs. See Table 1 for information on the System 450
control modules with this feature.

Analog output signal limiting

The analog output signal limiting feature on the System
450 control modules with communications reduces the
rate at which an analog output updates its output signal
strength in response to input signal changes.

When it controls a device such as a modulating actuator,
the analog output signal limiting feature can help
lengthen actuator life by reducing the actuator position
update frequency. The following parameters control this
feature:

• Output signal update rate: Select the rate in seconds
at which an analog output updates the output signal to
the controlled equipment

System 450 Series Modular Controls Product Bulletin 3

• Output signal dead band: Create a deadband for the
analog output signal within which the output signal
strength remains constant

See Table 1 for information on the System 450 control
modules with the analog output signal limiting feature.

Binary input control for relay outputs

A binary input is a user-supplied pair of dry contacts.
Connect a binary input to any of the three control module
input terminals and control the output relays in your
control system based on whether the binary input’s state
is open or closed. Examples of dry contacts include door
switches, timers, occupancy sensors, and other switching
devices.

A sensor set up as a binary input can be referenced
only by a relay output. Analog outputs cannot reference
sensors set up as binary inputs.

On/Off duration time control

Use the four time control parameters on the control
modules with communications to set up the relay outputs
with On or Off time delays and minimum On or Off times.

You can set each of the four On or Off duration control
parameters from 0 seconds to 300 seconds or 5 minutes,
in 1-second intervals.

Hybrid analog output control

The hybrid analog output control on C450CPW-400 control
modules enables an analog VDC output to transition to a
pulse output at low signal levels.

This function ensures more efficient low-speed control of
variable speed EC motors in condenser fan applications.

Network communications

The System 450 communications control modules provide
network connectivity and communications. Depending
on the communications control module, your controls
system can connect to and communicate over either
Ethernet networks or Modbus networks. See Table 1 for
information on the System 450 control modules with this
feature.

Ethernet communications

The System 450 control modules with Ethernet
communications have an integral web server that delivers
web pages to client browsers on desktop and laptop
computers, as well as smart phones, devices, and tablets.

Use the System 450 web UI to monitor your control
system status and set up or change the configuration
in simple, user-friendly web pages delivered to your
computer through a direct connection, a LAN connection,
or the internet.

Figure 4: System 450 System Overview page example

You can monitor control system status and configure the
control system parameters in both the local UI through
the LCD and four-button touchpad, and the web UI.

Use the System 450 control modules with Ethernet
communications to perform the following tasks:

• Directly connect your computer to the System 450
control module with an Ethernet cable, and set up,
monitor, and modify your control system

• Connect your control system to an existing network
and establish a static IP address or use a Dynamic Host
Configuration Protocol (DHCP) server to provide a
dynamic address

• Set up Dynamic Domain Name Server and browse to
your System 450 control system on a local network or
across the internet using a text-based host name URL
instead of a numeric IP address and port number

The System 450 web UI provides easy remote access to
your System 450 controls systems through your LAN or
the internet. Use the web UI to log on directly, locally, or
remotely and view the web UI system status, system setup
parameters, and parameter values in the UI.

Use the system configuration web pages to set up or
change the parameters for your system outputs in the
web UI. When the remote access lock feature is activated
in the web UI, users can view the control system status
but cannot make system changes.

RS485 Modbus communications

The System 450 control module with Modbus
communications is an RS485, RTU compliant Modbus
subordinate device. You can use it to connect your
System 450 control system to Modbus networks and
communicate over them.

The System 450 Modbus communication control module
also enables your entire control system to respond to data
requests and commands from a Modbus master device on
the Modbus network.

System 450 Series Modular Controls Product Bulletin4

Table 1: System 450 Control Module capabilities

Control by ________

Controlled condition

Temperature X X X X

Pressure X X - X

Humidity X X X X

Combination of
conditions

Control capabilities

On/Off relay control X X X X

Analog proportional
control (direct and
reverse action)

Analog proportional
plus integral control
(direct and reverse
action)

Combination of On/
Off relay and analog
output control

Stand-alone control X - X X

Multi-stage control
(relay or analog)

Network
communications

High input signal
selection

Differential control X X - X

Output signal
limiting

output signal
update rate
Output signal
deadband

Binary input control
for relay outputs

On/Off duration
time control

Minimum On/Off
time
On/Off time delay

Temperature and
humidity reset
control

Scheduling and
temperature
setback control

Reset setpoint
control

Setback scheduling - - X -

Run-time balancing - - X -

Hybrid analog
output control

1 Only on output OUTA1.

System 450 Control Modules

Standard Communications Reset Hybrid

C450CPN-4
C450CQN-4

C450CBN-4
C450CCN-4

C450CEN-1
C450CRN-1

X X X X

X X X X

X X X X

X X X X

X X X X

- X - -

X X - X

X X - -

X X - -

X X - -

- - X -

- - X -

- - X -

- - -

C450RBN-3
C450RCN-3

C450CPW-400

1

1

X

System 450 control modules

The System 450 control module is the supervisor of your
control system and the interface for the system’s inputs,
supply power, and outputs.

Figure 5 shows an example System 450 control module.
See Table 1 and Table 2 for information on all of the
available control modules.

Figure 5: C450CBN Standard control module

All System 450 control systems require a control module
to set up the control system’s inputs and outputs, monitor
the control system’s status, and control the system’s
outputs.

System 450 control modules can monitor up to three
inputs and control up to 10 outputs in any combination of
relay and analog outputs provided by expansion modules.

User-friendly LCD and touchpad UI

The System 450 control modules feature a backlit LCD
screen that displays the real-time status of the sensors
that are set up in your control system during normal
operation. The four-button touchpad enables you to
quickly scroll through and view the output status screens
and access the system setup screens to set up or adjust
the sensors and outputs in your control system.

After you assemble and power your control system, and
select the Sensor Types in the UI, the control module
automatically determines the output numbers and output
types. The control module then generates the menu­based setup screens and supplies all of the default setup
values required to set up your custom control system.

System 450 standard control modules

Configure the System 450 standard control modules out
of the box as stand-alone controls that can provide SPDT
control or proportional analog signal control, depending
on the model, for a wide range of HVAC, commercial, and
industrial process applications. The following standard
control modules are available:

• C450CBN-4 control module has one SPDT relay output

• C450CCN-4 control modules have two SPDT relay
outputs

• C450CPN-4 control modules have one analog output
(0VDC to 10 VDC or 4 mA to 20 mA)

• C450CQN-4 control modules have two analog outputs
(0 VDC to 10 VDC or 4 mA to 20 mA)

With a standard control module and the available sensors
and transducers, almost any temperature, pressure, or
humidity control you may encounter in the field can be

System 450 Series Modular Controls Product Bulletin 5

quickly replaced with a System 450 control system. See
Table 1 for capabilities of the standard control modules.

System 450 reset control modules

Reset control modules provide many of the features of the
standard control modules for temperature and humidity
control. In addition, these modules provide temperature
and humidity reset, real-time setback, and run-time
balancing capability. The following reset control modules
are available:

• C450RBN-3 (one SPDT relay output)

• C450RCN-3 (two SPDT relay outputs)
See Table 1 for capabilities of the System 450 reset control

modules.
Reset control modules control temperature and humidity,

but not pressure.

System 450 hybrid analog output control modules

A System 450 hybrid analog output control module
can provide the same control as the standard control
modules, while providing a hybrid analog output control
option for controlling EC motors.

The hybrid analog output control feature enables an
analog VDC output to transition to a pulse output at
low signal levels. This provides more efficient low­speed control of EC variable speed motors. These EC
variable speed motors are typically used in condenser fan
applications on a wide variety of refrigeration and HVAC
condensing units.

The onboard analog output can also be configured
for High Input Signal Selection, which enables precise
and efficient EC motor speed control on multi-circuit
condensing units.

See Table 1 for capabilities of the System 450 Hybrid
Analog Output control modules.

including multipurpose control systems that control
temperature, pressure, and humidity simultaneously.

You do not need to purchase additional and unnecessary
features and components associated with packaged
control systems, which reduces your control system costs
to just the inputs, outputs, and features required by your
application.

System 450 components allow you to build control
systems that include:

• one to 10 outputs provided by the control module and
expansion modules, each output providing either on/
off control or a proportional analog signal (0 VDC to
10 VDC or 4 mA to 20 mA) to the equipment in your
controlled system

• one to three sensors or transducers, which are hard­wired directly to the control module and provide input
signals for monitoring and controlling your system
equipment

• an optional power module to provide power to the
control module, expansion modules, and the input
sensors and transducers

Expansion modules

Figure 6: C450SCN Relay Expansion Module

System 450 control modules with communications

A System 450 control module with communications
provides the same types of control as the standard control
modules. See Table 1 for capabilities of the System 450
control modules with communications.

C450CEN-1 control modules feature an RJ45 Ethernet
network port that enables you to connect your control
system to an Ethernet network and communicate across
it.

C450CRN-1 control modules feature an RS485 terminal
block that enables you to connect your control system to
an RS485 MODBUS network and communicate on it.

System 450 communications control modules do not
provide onboard outputs and require expansion modules
to provide outputs.

Other System 450 components

The System 450 suite of components enables you to
build a wide variety of cost-effective, custom control
systems that meet your specific application requirements;

System 450 Series Modular Controls Product Bulletin6

The System 450 expansion modules allow you to increase
the number of outputs in your control system to meet
your application requirements. The following models are
available:

• C450SBN-4 or C450SBG-4: Relay expansion module with
one relay output

• C450SCN-4 or C450SCG-4: Relay expansion module with
two relay outputs (Figure 6)

• C450SPN-4: Analog expansion module with one analog
output

• C450SQN-4: Analog expansion module with two analog
outputs

For further information, see Ordering Information and

Technical Specifications.