CM332 PLC Based Circuit Management System
SPECIFICATION
APPLICATION
INFORMATION
Description of Circuit Management System
This heat trace circuit management system (CM332) provides
a compact, tightly integrated, factory assembled/tested
solution for high density plant locations. The unit is based on
a standard PLC platform, specifically integrated for use with
electric heat trace systems.
Benefits Include:
•
•
•
•
•
Optimized process control temperatures
Energy conservation
Elimination of separate ground fault branch circuit breakers
Automated trace heater monitoring
Predictive maintenance monitoring
Compliances and Certifications
Conforms to UL508A, Certified to CSA-22.2 No
14-05
• Ordinary Locations
• Hazardous (Classified) Locations
- Class I, Division 2
- Groups A, B, C, D
- Temp Code T4 (135ºC)
CM332-4-C-P
Description of System Functions:
Temperature Control
An RTD based temperature control function optimizes energy
consumption, while maintaining tight temperature control on
your process piping. High and low temperature alarms will
alert you to any upset conditions that could cause problems
with your processes.
Heat Trace Ground Fault Protection
The system provides continuous monitoring of ground
fault conditions with each circuit, eliminating the need for
expensive ground fault protection branch circuit breakers.
Separate values can be inserted for alarm and trip functions,
alerting you to problems before the problem becomes severe
enough to require the heat trace be taken out of service.
Adjustable trip values allow you to compensate for normal
capacitive ground fault leakage that occurs in cables.
Predictive Maintenance System
Ground fault and load current values are compared to earlier
values. Adverse trends in a trace heater will get that circuit
put on a maintenance log alert system. This log allows the
limited maintenance resources to be optimally deployed.
©2016 Nelson Heat Tracing Systems
Heat Trace Power Output Monitoring
Adjustable high and low load current alarms for each heat
trace circuit provide a constant monitor of the power output
of each heat tracer. A low current alarm can identify the loss
of a heater segment before the pipe can plug up and stop the
process. A high current alarm can identify a developing short
circuit in the tracer allowing the circuit to be taken off line with
a minimum of damage to the rest of the heat tracer.
Automatic Testing
The system will continuously test the system, even when it is
not in use. This allows any problems to be identified as they
occur, rather than allowing problems to cascade over a long
period. The unit turns each circuit on at selected intervals
and checks for ground fault leakage and load currents. Any
problems will be alarmed.
www.nelsonheaters.com
319-SA-021 Rev.1
CM332 PLC Based Circuit Management System
SPECIFICATION
APPLICATION
INFORMATION
Description
The system provides temperature monitoring and control of the trace heating system. The system automatically checks the health
of the trace heating system. Negative trends are noted on a maintenance pending list, while more severe problems are removed
from service and alarmed.
Key Features:
Temperature control
Heat Trace power control
Heat Trace
Load switching, 24 Amps- 277Vac or 600Vac
Adjustable ground fault alarm
Adjustable control temperature
Adjustable ground fault trip
Adjustable hi & lo temperature alarms
Adjustable low current alarm
Adjustable dead band
Adjustable high current alarm
Interface
Other
Color touch screen operator interface
High Density – 32 circuits
Displays all alarms
NEMA 12, 4, 4X constructions, purge for hazardous locations
Displays actual temperature
PLC based system
Displays heat trace circuit status- on or off
Modbus communications
Displays actual heat trace ground fault and load currents
Proven, robust heat trace control program
Displays all set points
Processor failure alarm
Global programming
RTD sensor probe failure
Intuitive, easy to navigate
All data accessible thru communications port
Automated monitoring
Testing of heat trace circuit – voltage, current, ground fault
Predictive maintenance, trend monitoring of heat trace
Touch Screen Functions
Operator interaction with the Nelson CM332 is provided by a touch sensitive screen with high resolution LED graphics. Developed with simplified operations in mind. Each main control and monitor function is designed for direct
user access. Automatic activation of a scrolling alarm banner and direct resetting of alarm relays are provided on the
main page, as well as a channel summary page providing individual alarm indication and direct access to the specific
channel status information.
Touch Screen Graphic Display HMI
•Analog touch pad, resolution 1024 x 1024
•Backlighting, CFL, up to 75,000 hours life
•Compact flash card application backup
•Direct access to status and setup pages
•Scrolling alarm status banner
©2016 Nelson Heat Tracing Systems
Intuitive Operator Interfacing
•Direct channel selection, reduced access time
•Real-Time status of individual control channels
•Temperature, load current, and ground fault leakage values
•Heater output and alarm status indication
•Ground fault trip reset function
www.nelsonheaters.com
319-SA-021 Rev.1
CM332 PLC Based Circuit Management System
Simplified Controller Setup Features
•Direct access to control system setup options
•Control system override function
•Individual channel or global programming option
•Display settings for contrast, brightness, and comm
•Password protected
Programming Screen – Temperature Control
•Individual channel input values
•Control setpoint
•Control deadband
•Hi and lo temperature alarm settings
•Selectable sensor failure mode
•Password protected
©2016 Nelson Heat Tracing Systems
SPECIFICATION
APPLICATION
INFORMATION
System Setup Features
•Selectable temperature units, ºF or ºC
•Ground fault alarm/trip delay option
•Automatic test-cycle enable and programming
•Password protected
Programming Screen – Heater Monitoring
•Individual channel input values
•Hi and lo load current alarm settings
•Individual ground fault alarm setting
•Individual ground fault trip setting
•Selectable ground fault trip control mode
•Password protected
www.nelsonheaters.com
319-SA-021 Rev.1
CM332 PLC Based Circuit Management System
SPECIFICATION
APPLICATION
INFORMATION
Specifications:
Ground fault alarm 1-500ma, adjustable
50/60 Hz
Ground fault trip 1-500ma, adjustable
277Vac (R2), 600Vac (C)
Heat trace low current alarm 1-30 amps, adjustable
24 amps
Heat trace high current alarm 1-30 amps, adjustable
Modicon M340 platform
Auto-Test cycle 1-720 hrs, adjustable
Display Color LED, CFL 75,000h
Predictive maintenance log On or off
Operator interface Analog touch pad,
Predictive log trigger values adjustable
1,024 x 1,024
Sensor inputs RTD, 100 ohm, platinum,
Control 120-240Vac, 1-phase,
Heat trace load Controller Programming options 3-wire
By channel or global
On or off for each channel
Temperature Units °F or °C
Sensor failure mode Channel (circuit) activation On or off for each channel
Alarm contact Common for all alarms
Alternate alarm contact Ground fault only
adjustable
Ambient temperature -20°C to +40°C
Control dead band adjustable
Relative humidity, NEMA 12 0-85%, non-condensing
High temperature alarm adjustable
Relative humidity, NEMA 4, 4X 0-100%
Low temperature alarm adjustable
Enclosure options NEMA 4, 4X and 12
Approvals ETL Control: 4000560
Control temperature set point -328 to +1392 °F range,
Nelson’s CM332 Circuit Management System is available in multiple configurations of circuit count, enclosure ratings
and power ratings. The selection tables below allow for the proper specifying of the standard systems
(example: CM332-4X-R2). For custom configurations or modifications, consult factory.
CM3
32
–
4X
–
R2
–
EC
SPECIFY OPTIONS
ET - Ethernet capable HMI with web gate
EC - External Modbus® communications
NC - External Modbus TCP/IP Ethernet Communications
P - Type Z purge for CI, D2 installations
SPECIFY POWER OUTPUT MODULES
R2 - 24A @ 277 Vac, DPST switching
C - 24A @ 600 Vac DPST switching
SPECIFY ENCLOSURE TYPE
4-N
EMA 4, polyester powder coated steel
4X - N
EMA 4x, type 304 stainless steel
12 - N
EMA 12, polyester powder coated steel
Select multiples of 8 circuits up to 32 circuits
©2016 Nelson Heat Tracing Systems
www.nelsonheaters.com
319-SA-021 Rev.1