Nelson CM-2201 User Manual

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NELSON

HEAT TRACE CONTROLLER

Installation and Operating Instructions

CM-2201

Contents CM-2201

1.0 Introduction 4

1.1 Getting Started

2.0 General Application Information 5

3.0 Installation 6

3.1 Selecting Installation Location

3.2 Mounting

3.3 Wiring

4.0 Initial Set-up

4.1 Display Modes

4.2 Password Protection

4.3 Security Levels

5.0 General Operation 7

5.1 Display

5.2 Keypad

5.3 LED Functions

5.4 Monitoring

5.5 Alarm Management

5.6 Soft-Start Feature

5.7 Current-Limiting Feature

5.8 Ground Faults

6.0 Control Modes 8

6.1 On-Off Control

6.2 Proportional Control

6.3 Forced Control Feature

7.0 Programming 9

7.1 Setpoints

7.2 Heater Setup

7.3 System Setup

8.0 Communications 15

9.0 Troubleshooting 16

10.0 Maintenance 20

CM-2201 Contents

Appendix A – Speciﬁcations 21

Appendix B – Wiring Diagrams 22

Appendix C – Typical Installation Diagram 23

Appendix D – Modbus Parameters 24

Appendix E – RTD Tables 29

Appendix F – Warranty 38

Introduction CM-2201

1.0 Introduction

The Nelson Heat Trace CM-2201 is designed to monitor and control one heating circuit in ordinary and Class I, Division 2, Class I, Zone 2, and Zone 2 hazardous locations. This manual provides information pertaining to the installation, operation, testing, communications and maintenance of this device. See Appendix A for additional details.

1.1 Getting Started

The CM-2201 should be connected to external RTDs; power and communication based on Appendix B and C. If any problems occur, call Nelson technical support or follow the Troubleshooting section.

CM-2201 Application Information

2.0 General Application Information

The CM-2201 is designed to operate on input voltages between 100 and 277 Vac and 50/60 Hz. Load switching is handled by a 2-Pole solid-state relay and can control resistive loads of 30A continuous @ 40°C ambient.

The CM-2201 is designed to control one heating circuit by monitoring one or two temperature inputs via industry standard 3-wire, 100Ω, Platinum RTDs. Two separate RTDs may be utilized to customize the temperature control inputs. Several different modes are user selectable as well as the sensor failure operational mode.

The CM-2201 assembly is rated UL Type 4X (IP66) and can be operated in temperatures of -40°F to +104°F (-40°C to +40°C).

Installation and Initial Set up CM-2201

3.0 Installation

The CM-2201 must be installed only in areas for which it has been approved and in accordance with all applicable electrical codes and ordinances. All conduit entry holes must be appropriately installed and sealed to maintain ingress protection rating.

Do not install this unit prior to functional testing if shipping container or internal packaging shows signs of damage. Notify the appropriate individuals immediately if damage is suspected.

3.1 Selecting Installation Location

The CM-2201 should be installed in an area protected from the elements as much as possible. It is possible to install the unit in unprotected areas, but such often limits maintenance/access. Further, installation in unprotected areas must be carefully considered to ensure it is always in operating conditions consistent with speciﬁcations. See Appendix A for additional details.

3.2 Mounting

The CM-2201 should be mounted at a convenient height to suit operator interaction. Conduit entries should be made in the bottom of the enclosure to prevent damage to the internal electronics from moisture intrusion. Conduit entries should be drilled, and the use of suitable bushings is required to maintain the environmental ratings.

3.3 Wiring

Electrical wiring diagrams and schematics are provided in Appendix B and C of this manual. Ensure that all wiring and connections are in accordance with applicable wiring codes. Enclosure grounding must be in accordance with applicable wiring codes for non-metallic devices.

4.0 Initial Set-Up

Upon initial power-up, the CM-2201 display will run selfcheck, display the software version, then the main program will start.

4.1 Display Modes

This feature determines what messages and functions are displayed during normal operations. If set to “normal user,” only basic information is displayed. If set to “advanced user,” all controller information is displayed. Each parameter shown in this manual will list the Display Mode required to view information and access each function during programming.

4.2 Password Protection

The CM-2201 can have password protection enabled to ensure that sensitive operating parameters are not inadvertently adjusted. If password protection is enabled, the user will be prompted to enter a valid value to access any protected features. The user may also replace the default password value (1,2,3,4) with their own unique value for greater protection of operational parameters. The password can be disabled indeﬁnitely if no protection is desired.

4.3 Security Levels

CM-2201 has two levels of security; the high level (Advanced Display) uses password protection. Disabling the password from the Password Enable / Disable menu will keep the password disabled indeﬁnitely – any parameter can be changed without the use of a password. At this level, all the functions and monitoring parameters are open. The low level (Normal Display) does not give access to parameter settings, but is open for monitoring a few parameters, such as temperature, current, GFI, etc.

If the password is “Enabled”, by going to the parameter to be changed, after the ‘up’ or ‘down’ arrow is pressed, the controller will ask to type the password, and after that, the parameter can be changed and saved. The password will stay disabled for 15 min, then be automatically re-enabled. During the 15 min period when the password is disabled, other parameters can be changed and saved.

CM-2201 General Operation

5.1 Display

The CM-2201 utilizes a 2 line x 16 character alphanumeric display, viewable from the front keypad. The top line is reserved for the function or operation and the bottom line displays the value range.

5.2 Keypad

The keypad is touch sensitive. The operator must touch the area on the main label and the controller will respond.

5.3 LED Functions

LED indicators will show the status of the respective functions. The power LED will be illuminated when the controller is connected to a source voltage. The heater LED will be illuminated when voltage is applied to the heater. The system LED will illuminate if there is an internal hardware issue with the controller. The comm LED will illuminate when the controller is sending data through external communication. The alarm LED will ﬂash when there is a current active alarm condition; the alarm LED will illuminate solid when an alarm was present, but is not currently active.

5.4 Monitoring

By touching the “Actual” button, followed by an arrow, the controller will display all the active parameters, one at a time.

5.5 Alarm Management

All the alarm(s) will be saved in the alarm log. If the alarm is not active (alarm LED solid red), the Alarm LED can be turned off by touching “Reset”, one alarm at a time. If the alarm is active (alarm LED ﬂashing red), the user cannot reset the alarm.

5.6 Soft-Start Feature

The Soft-Start feature enables self-regulating cables to be energized at low temperatures without causing excessive load on the electrical system, and extends cable life by reducing cable internal heating due to inrush currents. The resistance of self-regulating cables decreases as these cables get colder, which results in higher current draw.

5.6 Soft-Start Feature Continued

This can result in breaker trips if temperatures are very cold and the installed length of cable is high. The Soft-Start feature operates by initially only energizing the cable for a very short period of time – while the current draw may be high during this period, the period is usually short enough to reduce average load on the electrical system. This short energization period is repeated and eventually increased; after a few minutes, the cable is usually warm enough such that the resistance has increased and the current decreased to the point where it can be continuously energized.

5.7 Current-Limiting Feature

The Current-Limiting feature operates similarly to the Soft-Start in that it restricts the amount of time the cable is energized during any given period, thereby reducing the average current draw of the cable during that period. For example, if a cable normally draws 8 Amps, but current limit is set to 6 Amps, then the cable would be energized only 75% of the time.

5.8 Ground Faults

Ground faults typically are the result of damaged or improperly installed cables which allow current-carrying conductors/surfaces/parts to be in contact with grounded objects. For example, if a heating cable has been secured to a pipe with a clamp, and if the clamp has been overtightened, then the ground braid and/or the pipe may come in contact with current carrying parts within the cable. This would result in current leakage to ground through the ground braid of the cable and/or the pipe itself. This type of fault can eventually become serious, resulting in overheating/ﬁre/shock hazards. Current leakage to ground can be monitored by electronic circuitry, and the SPC can be programmed to either alarm or trip when leakage current exceeds the speciﬁed maximum allowable amount.

Control Modes CM-2201

6.0 Control Modes

The CM-2201 allows the user to select different control modes based on their individual process control parameters.

6.1 On-Off Control

This control method simply energizes the cable until the actual monitored temperature rises to the setpoint value plus half the deadband value (upper limit). The cable is then de-energized until the actual monitored temperature drops to the setpoint value minus half the deadband value. Note that this type of control can result in some temperature “overshoot”; this is because the cable is de-energized when the monitored temperature reaches the upper limit. However, the residual heat in the cable continues to transfer to the pipe, and this will cause the pipe temperature to increase slightly above the upper limit. Similarly, there can be some temperature “undershoot”.

6.2 Proportional Control

This control method uses the typical proportional control algorithm, wherein the cable is cycled on and off at a rate proportional to the difference between the setpoint value and the actual monitored temperature. As the difference between the setpoint value and the actual monitored temperature increases, the amount of time the cable is energized increases proportionately. This helps reduce the “overshoot” and “undershoot” commonly associated with On/Off control.

6.3 Forced Control Feature

This control method simply allows the user to force the cable on or off as desired.

CM-2201 Programming

7.0 Programming

7.1 Program - Setpoints

7.1.1 Setpoint Value

This message displays the name of the sub-menu when entered.

1. Display Mode: All

2. Range: N/A

3. Default: N/A

7.1.2 Maintain Temp

This value sets the control setpoint temperature for all operating modes. For On-Off control, the circuit is energized if the control temperature is less than the maintain temperature minus the deadband. The circuit is de-energized if the control temperature is greater than the maintain temperature plus the deadband. If maintain temp is set to None then the heater circuit will have temperature monitoring with no control temperature. If the maintain temp is set to Off then the heater circuit will have no temperature monitoring or control.

1. Display Mode: All

2. Range: -50°C to 500°C, none or -58°F to +932°F, none, Off

3. Default: 10°F or 50°F

7.1.3 Low Temp Alarm

This value sets the Low Temperature Alarm setpoint. It must be less than the maintain temperature minus the Deadband. To disable this alarm set the value to “Off’. When the measured temperature of either RTD A or RTD B (if activated) is less than or equal to this setpoint, the Low Temperature Alarm is activated and a “LOW TEMP ALARM” message is added to the alarm stack. This alarm deactivates when the temperature rises above the alarm setpoint value.

1. Display Mode: All

2. Range: -50C to Maintain Temperature, Off, -58°F to Maintain Temperature, Off

3. Default: 5°C or 41°F

4. Restrictions: Message does not exist if Maintain Temperature is set to Off.

7.1.4 High Temp Alarm

This value sets the High Temperature Alarm setpoint. It must be greater than the maintain temperature plus deadband. To disable this alarm set the value to “Off”. When the measured temperature of either RTD A or RTD B (if activated) is greater than or equal to this setpoint, the High Temperature Alarm is activated and a “HIGH TEMP ALARM” message is added to the alarm stack. The alarm deactivates when the temperature falls below this alarm setpoint.

1. Display Mode: All

2. Range: Maintain Temperature to +500°C, Off, Maintain Temperature to +932°F, Off

3. Default: Off

4. Restrictions: Message does not exist if Maintain Temperature is set to Off.

7.1.5 Low Current Alarm

This value sets the Low Current Alarm setpoint. It must be less than the high current alarm setpoint. To disable this alarm set the value to “Off’. When the heater current is less than or equal to this setpoint, the Low Current Alarm is activated and a “LOW CURRENT ALARM” message is added to the alarm stack. The alarm deactivates when the Heater Current rises above this alarm setpoint. Note: This setpoint is based on the heater at 100% power. If Proportional Control or Current Limiting is enabled, all current measurements will be scaled to 100% power, based on a constant resistive load, before being compared to the alarm setpoint.

1. Display Mode: All

2. Range: 0.1A to High Current Alarm, Off

3. Default: Off

7.1.6 High Current Alarm

This value sets the High Current Alarm setpoint. It must be greater than the low current alarm setpoint. To disable this alarm set the value to “Off’. When the heater current is greater than or equal to this setpoint, the High Current Alarm is activated and a “HIGH CURRENT ALARM” message is added to the alarm stack. The alarm deactivates when the heater current falls below this alarm setpoint. This setpoint is based on the heater at 100% power.

Programming CM-2201

7.1.6 High Current Alarm Continued

If Proportional Control or Current Limiting is enabled, all current measurements will be scaled to 100% power, based on a constant resistive load, before being compared to the alarm setpoint.

1. Display Mode: All

2. Range: Low Current Alarm to 30.0A, Off

3. Default: Off

7.1.7 Ground Fault Alarm

This value sets the Ground Fault Alarm setpoint. It must be less than the ground fault trip setpoint. To disable this alarm set the value to "Off'. When the Ground Fault Current is greater than or equal to this setpoint, the Ground Fault Alarm is activated and a "GROUND FAULT ALARM" message is added to the alarm stack. The alarm deactivates when the Ground Fault Current falls below this alarm setpoint.

1. Display Mode: All

2. Range: 10 to Ground Fault Trip, Off

3. Default: 30mA

7.1.9 Low Voltage Alarm Continued

1. Display Mode: All

2. Range: 85VAC to High Voltage Alarm, Off

3. Default: Off

7.1.10 High Voltage Alarm

This value sets the High Voltage Alarm setpoint. It must be greater than the Low Voltage Alarm setpoint. To disable this alarm set the value to “Off’. When the Heater Voltage is greater than or equal to this setpoint, the High Voltage Alarm is activated and a “HIGH VOLTAGE ALARM” message is added to the alarm stack messages. The alarm deactivates when the Heater Voltage drops below this alarm setpoint.

1. Display Mode: All

2. Range: Low Voltage Alarm to 280VAC, Off

3. Default: Off

7.2 Program - Heater Setup

7.1.8 Ground Fault Trip

This value sets the Ground Fault Trip setpoint. It must be greater than the ground fault alarm setpoint. To disable this trip alarm set the value to “Off’. When the Ground Fault Current is greater than or equal to this setpoint, the heater circuit is de-energized, the Ground Fault Trip Alarm is activated and a “GROUND FAULT TRIP” message is added to the alarm stack. This is a latching alarm and trip. When the cause of the alarm has been corrected, the circuit may be energized by the manual reset function.

1. Display Mode: All

2. Range: Ground Fault Alarm to 500mA, Off

3. Default: 50mA

7.1.9 Low Voltage Alarm

This value sets the Low Voltage Alarm setpoint. It must be less than the high voltage alarm setpoint. To disable this alarm set the value to “Off’. When the Line Voltage is less than or equal to this setpoint, the Low Voltage Alarm is activated and a “LOW VOLTAGE ALARM” message is added to the alarm stack. The alarm deactivates when the Line Voltage rises above this alarm setpoint.

7.2.1 Heater Setup

This message displays the name of the sub-menu when entered.

1. Display Mode: Advanced

2. Range: N/A

3. Default: N/A

7.2.2 Enable Heater

This selection enables control and monitoring of the heater circuit. Setpoints and measured value messages cannot be accessed unless the heater is enabled. Select “No” if the circuit is not used.

1. Display Mode: All

2. Range: yes, no

3. Default: yes

CM-2201 Programming

7.2.3 Heater ID

This selection allows for user deﬁned Heater Identiﬁcation. It provides a unique, identiﬁable tag or label for each heater circuit. The Heater Name allows up to 20 alphanumeric characters which are entered one at a time from left to right. The cursor indicates which character is being selected. Press the [SELECT UP/DOWN] arrow keys to change the character. Move to the next character by pressing [NEXT] arrow. Press [ENTER] in the last character position to save the Heater ID.

1. Display Mode: Advanced

2. Range: 20 Characters

3. Default: Blank

7.2.4 Manual Override

This selection sets the response of the heater circuit to the Override inputs. The Override inputs respond to contact closure. If the Override is set to “Off”, the override inputs are ignored and control of the heater circuit operates normally based on the measured temperature and maintain temperature setpoint. If the Override is set to “On”, an open contact on the override inputs forces the heater Off. When the contact on the override input is closed, the heater control resumes in normal manner.

1. Display Mode: Advanced

2. Range: On, Off

3. Default: Off

7.2.5 Deadband

The Deadband is deﬁned as the difference between the setpoint temperature and the actual maximum temperature that is ideally allowed in excess of the setpoint temperature. Decreasing the deadband increases the temperature control accuracy but also increases the heater switching frequency.

1. Display Mode: Advanced

2. Range: 1 °C to 5 °C, 1 °F to 10 °F

3. Default: 2 °C or 5 °F

4. Note: Deadband is disabled for Proportional Control mode.

7.2.6 Control Type

This selection determines the type of control method used by the controller: either On-Off (Deadband), or Proportional Control. The On-Off control mode is available for all heating devices. Proportional Control mode is only available for series type heating devices.

Warning: Proportional Control should never be selected for use with self-regulating heating cable types due to the constantly changing characteristics of self-regulating cables – this will cause the control to be unstable. Further, the continual cycling associated with Proportional Control can result in internal heating of the cable and lead to reduced life expectancy.

1. Display Mode: Advanced

2. Range: On-Off, Proportional

3. Default: On-Off

4. Selection does not exist if Maintain Temperature is set to Off.

7.2.7 Current Limiting

This selection sets the maximum average current limit allowed for the heater circuit. It is useful for reducing the power output of constant wattage heaters. The load will be turned on for a period of time, then turned off for a period of time to maintain the average current draw to the value set.

1. Display Mode: Advanced

2. Range: 0.5 to 30.0 A, Off

3. Default: Off

4. Note: The value range is in 0.5A increments.

7.2.8 Soft Start Mode

This function ramps the heater output from Off to nominal current of the heater over the set softstart cycle time. It is useful for reducing inrush currents of self-regulating heaters. At the end of the soft start cycle time, the load will no longer be controlled by the soft start function.

1. Display: Advanced

2. Range: 10 to 999 seconds, Off

3. Default: Off

Programming CM-2201

7.2.9 Auto Test Cycle

This value sets the frequency at which the Auto Test Cycle is activated. Auto Test is a feature that exercises the system by automatically applying power to the heater at speciﬁed time intervals. If an alarm condition is detected during this period, the Auto Test Alarm is activated and an “ALARM DURING AUTO TEST” message is added to the System Status messages. This is a latching alarm. To clear the alarm, locate the alarm message in the Alarm Menu and press [ENTER]. To disable this feature, set the value to “Off”. The Auto Test Cycle does not operate if heater is forced off for any reason, including ground fault trip. Auto Test decreases maintenance by providing an early warning of problems that would otherwise go undetected until the heater was needed.

1. Display Mode: Advanced

2. Range: 1 to 720 hours, Off

3. Default: 24 hours

7.2.10 RTD Operation

This selection determines how the control temperature is utilized by the RTD inputs.

In One RTD Mode, the temperature is based on the measured temperature from RTD-A.

In Backup Mode, control temperature is based on RTD-A. If for any reason RTD-A fails, then RTD-B takes over.

7.2.10 RTD Operation Continued

Functions requiring two RTDs to operate, such as Average, Lowest, Highest and High Temperature Cutoff, will operate in One RTD mode if one of the two RTDs fail.

1. Display Mode: Advanced

2. Range: One RTD, Backup, Average, Lowest, Highest, High Temperature Cutoff

3. Default: One RTD

4. Restrictions: Message does not exist if Maintain Temperature is set to Off.

7.2.11 RTD Failure Mode

This selection sets the controller’s fail-safe mode. The controller detects if RTD-A has failed and will use RTD-B if available. If RTD-B is not installed or has also failed, the heater will be set to its fail-safe state as selected in this mode. For freeze protection where there is no hazard from overheating, you may select “On” to operate the heater continuously and prevent freeze up.

For processes where there is a potential hazard from overheating, you may select “Off”, to de-energize the circuit until one of the RTDs becomes available.

1. Display Mode: Advanced

2. Range: On, Off

3. Default: Off

4. Restrictions: Message does not exist if Maintain Temperature is set to Off.

In Average Mode, the control temperature is based on the average of RTD-A and RTD-B measured temperatures.

In Lowest Mode, control temperature is based on the lowest of the two temperature measurements.

In Highest Mode, control temperature is based on the highest of the two temperature measurements.

In High Temperature Cutoff Mode, control temperature is based on RTD-A, but if the temperature from RTD-B exceeds the high temperature alarm, the heater is turned Off and a high temperature alarm is activated. The High Temperature cutoff mode will operate in One RTD mode if the high temperature alarm is turned Off.

7.3 Program – System Setup

7.3.1 System Setup

This message displays the name of the sub-menu when entered.

1. Display Mode: Advanced

2. Range: N/A

3. Default: N/A

7.3.2 Password

This selection determines if password protection is required for programming changes. The display will show “Disabled” if program access is currently enabled, and show “Enabled” if program access is currently disabled.

1. Display Mode: All

2. Range: Enabled or Disabled

3. Default: Enabled

CM-2201 Programming

7.3.3 Change Password

This selection allows the user to change the default password. The user is prompted to enter the old password, press [ENTER]. If veriﬁed, the user is then able to enter the new password, press [ENTER]. The user is prompted to re-enter the new password. By not entering a password and pressing [ENTER], the controller assumes no password.

1. Display Mode: Advanced

2. Range: Any combination of 2 to 16 characters 0 – 9, A – Z.

3. Default: 1234

7.3.4 Units

This selection determines the unit of measure for temperature values. All temperatures are displayed in the selected units of either Celsius degrees (°C) or Fahrenheit degrees (°F).

1. Display Mode: Advanced

2. Range: Celsius, Fahrenheit

3. Default: Celsius

7.3.5 Operational Costs

This value sets the cost per kWh of electrical power. This is used to calculate energy costs for operating this control circuit.

1. Display Mode: Advanced

2. Range: $0.01 to 1.00

3. Default: $0.05

7.3.6 Display Mode

This selection determines what messages are displayed by the controller for operations personnel. If set to “advanced user”, all messages are displayed. If set to “normal user,” only the basic messages are displayed. Each message listed throughout this manual shows the Display Mode required to see the message. “Advanced only” indicates that the display mode must be set to “advanced user” to view the message.

1. Display Mode: All

2. Range: Normal, Advanced

3. Default: Advanced

7.3.7 Default Display

This function speciﬁes the information that will be displayed when no key has been pressed for the Display Timeout interval as described below.

VALUE INFORMATION

DISPLAYED

System status Alarm status of all the

heaters

Heater status Alarm status of the

heater

Heater temp Temperature of the

heater

1. Display Mode: Advanced

2. Range: System Status, Heater Status, Heater Temp

3. Default: system status

4. Restrictions: Temperature messages are not displayed if Maintain Temperature is set to Off.

7.3.8 Display Timeout

This function sets the length of time from the last key press to automatically return to the Default Display information. Selecting “Off’ disables this function.

1. Display Mode: Advanced

2. Range: 5 to 600 seconds, Off

3. Default: 120 seconds

7.3.9 Modbus Address

This selection sets a unique address to ensure only one CM-2201 attempts communications with the master unit at any time. See Section 8.0 for complete information on Modbus communications.

1. Display Mode: Advanced

2. Range: 1 to 255 to accommodate multiple devices on same network.

3. Default: 1

7.3.10 Baud Rate

Sets the communication baud rate for the RS485 serial port. All controllers connected to the same data highway must operate on the same baud rate.

1. Display Mode: Advanced

2. Range: 1200, 2400, 4800, 9600, 19200

3. Default: 9600

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Nelson CM-2201 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual