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Nelson™ Heat Trace CM 2201 Single Point Circuit Management System
Nelson™ Heat Trace™ CM 2201 Single Point Circuit Management System
Nelson™ Heat Trace CM 2201 single point circuit management system is a microprocessor based digital control and monitoring system that has been specifically designed for stand-alone or networked electric heat tracing applications.
This system provides temperature control and heater cable monitoring while communicating additional information to operations personnel such as temperature alarms, voltage and current alarms, ground fault leakage, sensor failures and communications failures.
Nelson™ Heat Trace CM 2201 Single Point Circuit Management System


Certifications and Compliances
CSA Certified: Hazardous (Classified) Locations
Class I, Division 2, Groups A, B, C, D; Class I, Zone 2, Groups IIC; Temperature Code T4 (+135 °C)
NEMA Type 4X
Molded fiberglass polyester
Ambient Temperature
-40 °C to + 40 °C (-40 °F to +104 °F); Start up at -20 °C (-4 °F)
Temperature Input
Range: -50 °C to +500 °C (-58 °F to 932 °F). Accuracy: ±2 °C. Repeatability: ±1 °C. RTD: 100 ohm platinum, 3W RTD, (lead compensated up to 20 ohms). RTD Configuration: single, backup, highest, lowest, average or high
Heater Switching
Configuration: Two-pole, dual SSR per phase, 800 Amp, 1 cycle inrush. Ratings: 100-277 Vac, 30 Amp continuous. Line Frequency: 50 or 60Hz. Current Measurement: 0.1 to 40A 3% ±0.1 Amp. GF Measurement: 10 to 500 mA 5% ±2 mA. Voltage Measureme
Control Power
Power Requirement: Control power from heater voltage, 110-277 Vac
Port: (1) RS-485. Protocol: Modbus™ RTU. Transmission Rate: up to 115 Kbps. Wiring: 2-wire, shielded, twisted pair.
Measured Values
Temperature (Min. and Max.): -50 to +500 °C (-58 to +932 °F). Heater Current: 0.1 to 30 Amp. Ground Fault Current: 10 to 500 mA. Min. Heater Voltage: 90 Vac. Max. Heater Voltage: 305 Vac.
User Interface
16-character x 2-line LCD alphanumeric display. Controller parameters password protected. Panel Indicators: Power/heater on. Serial communication active. System failure. Process alarm. Keypad: 9 polyester keys. Actual, alarm, program, reset. Select up, s
Operating temperature: -40 °C to +40 °C, starting at -20 °C. Conformal Coating: Boards conformal coated for hostile environments
10H x 8W x 6D, NEMA Type 4X molded fiberglass polyester enclosure. Quick release latches to open door
Alarm Output
Alarm: Normally Open contacts. One DC opto-isolated contact. One AC opto-isolated contact. Alarm Rating: DC contact, 30 Vdc/100 mA max. AC contact: 24-277 Vac @ 0.5A max. Alarm Output: LED Indication
Alarm Function
Temperature: High temperature alarm/low temperature alarm. Current: Low current alarm/high current alarm. Ground Fault Current: Ground fault current alarm/ground fault current trip. Voltage: High voltage alarm/low voltage alarm. Hardware: Self-check fail


  • The circuit management system is housed in a NEMA 4X durable molded fiberglass polyester enclosure that can be wall or rack mounted. The system is provided with dual pole solid-state heater switching and is environmentally hardened for use in various pla
  • Easy to use interface: The 2 line, 16 characters/row, alphanumeric LCD display enables the use of English language prompts for set point entry and operation. There are no cryptic codes or key press combinations to remember
  • On/off or proportional control: The desired control mode can be easily selected via the front panel user interface
  • Ground fault alarm and trip settings: Separate alarm and trip settings for ground fault interrupt allow alarming of developing faults prior to circuit interruption
  • Dual RTD input: The optional second RTD can easily be configured in a variety of ways, including working with one RTD/two RTDs and high temperature cutout
  • Programmable auto test cycle: The user can select an interval from 1 to 24 hours to have the unit automatically check the heater operating current and ground fault conditions. This allows problems to be detected and fixed before the heating system is nee
  • Host communications: The RS-485 Modbus™ RTU communications capability is included as a standard feature. There are no expensive ""daughter boards"" or firmware updates required
  • LCD display is 2 Line, 16 characters per row
  • 30 A max (resistive load only) current rating with 0.1 to 40 Amp current monitoring
  • 100 Vac to 277 Vac voltage range with 10 mA to 500 mA ground fault monitoring