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.
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).
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.
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.
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.
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.
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.
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.
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.
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
12
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.
VALUEINFORMATION
DISPLAYED
System statusAlarm status of all the
heaters
Heater statusAlarm status of the
heater
Heater tempTemperature 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.
This selection resets controller memory parameters to
factory default values. If the controllers memory becomes
corrupt, resetting the module will force the controller to
overwrite each register and may correct any problems that
exist.
1. Display Mode: Advanced
2. Range: yes, no
3. Default: no
7.4 Program - System Test
7.4.1 System Test
This message displays the name of the sub-menu when
entered.
1. Display Mode: Advanced
2. Range: N/A
3. Default: N/A
7.4.4 Ground Fault Test
This function will test the ground fault trip function of the
controller to ensure proper operation. When selected, the
controller will generate an artificial ground fault current; if
the ground fault current is sensed as being greater than 30
mA, the test passes. The GF test function will verify actual
ground fault current and heater trip. Status of the test will
be displayed as pass or fail. If this test has been invoked
by the “Now” option and it passes, the user is prompted to
reset the ground fault trip, at which time the load is capable of being re-energized as required. If this test has been
invoked by the “Autotest” option, and it passes, the load is
allowed to be reenergized as required. If this test has been
invoked by the Autotest cycle, and it fails, an Autotest alarm
is generated, but the load is allowed to be reenergized as
required.
1. Display Mode: Advanced
2. Range: Autotest cycle, Now, Disabled
3. Default: Disabled
7.4.2 Alarm Output Test
This function is used for testing and commissioning
purposes allowing the alarm output to be forced On, either
for a short period of time, or continuously. At the end of the
specified time duration, the testing option is automatically
disabled. The alarm test function will not operate if the
alarm configuration is set to “Disabled”; the message
“ALARM DISABLED” will appear.
1. Display Mode: Advanced
2. Range: 1-24 hours, Disabled, Continuously
3. Default: Disabled
7.4.3 Heater Test
This function overrides heater control for maintenance
purposes. For normal operation, set to “Disabled”. If a
period of time is selected, the heater is forced On or Off for
the selected interval. If “continuous” is selected, the heater
is forced On or Off until “Disabled” is selected.
Upon receipt of the controller, or to check the controller for
an indication of normal operation, follow the operational
procedures shown below. These procedures are designed to
familiarize the operator with the controller and to provide an
understanding of its operation.
In order to determine if a fault is associated with the
heat tracing, wiring, or the controller, it will be necessary
to troubleshoot the wiring and tracer circuit. If the
fault remains, remove power from the controller and
exchange it with another controller. This may require some
reprogramming of the new CM2201. Refer to the following
sections for the appropriate topic.
9.1.1 RTDs
RTD failures after installation can generally be attributed
to incorrect wiring or improper installation of the sensor.
Troubleshooting of these failures is a very simple procedure
if the proper steps are undertaken in the correct order.
Some specific RTD problems and the correct methods for
troubleshooting are outlined as follows.
1. RTD Failure Alarm(s)
If the CM2201 controller indicates a failure of an RTD:
a) Ensure that the RTD is a 3-wire 100Ω (Platinum Type).
TURN THE POWER TO THE CONTROLLER OFF BEFORE
PROCEEDING!
b) Disconnect the RTD wiring from the input terminals.
c) Measure the RTD’s resistance between the source (RED)
and sense (RED) leads at the controller (it should not
exceed 40 Ω). Excessive lead resistance will cause an
RTD FAILURE ALARM, and must be corrected. Look for
loose terminals, excessive lead length, or insufficient
wire gauge, and correct as necessary.
d) Measure the RTD’s resistance between the source (RED)
or sense (RED) lead and the common (WHT) lead of the
RTD at the controller (should be between 60 and 330 Ω
depending on the temperature and the lead resistance.
Verify that the RTD is wired correctly—the heat tracing
controllers will always be terminated in the order: source
(RED), common (WHT), sense (RED). When wiring to the
CM2201, the terminals are marked as follows:
GND BusShield
R1RTD 1 Source (RED)
W1RTD 1 Common (WHT)
R1RTD 1 Sense (RED)
GND BusShield
R2RTD 2 Source (RED)
W2RTD 2 Common (WHT)
R2RTD 2 Sense (RED)
The RTD manufacturer will typically color code the leads
with the source and sense being the same color, and the
common a different color. Ensure that the RTD extension
wire shield is terminated at one end only, normally using the
terminal block provided at the terminal board.
Note: Some manufacturers use the common Black-WhiteRed triad color code for the RTD connections. Usually,
the RED lead is the common connection (same as the
White-White-Red color scheme) and the White and Black
connections may be used interchangeably.
2. Temperature Verification
If you feel that the indicated or displayed temperature is not
correct, the controller and the RTD can be quickly checked
for correct operation. To verify the RTD:
TURN THE POWER TO THE CONTROLLER OFF BEFORE
PROCEEDING!
a) Disconnect the RTD wiring from the input terminals.
b) To calculate the temperature indicated by the RTD,
measure the resistance from source (red wire) or sense
(red wire) to common (white wire) and subtract the
resistance measured between source and sense. This will
give a compensated resistance value that can be crossreferenced to one of the RTD tables found in Appendix
E or Appendix F. Compare the measured resistance and
cross-referenced temperature value obtained from the
RTD table to the indicated or displayed value. These
should agree to within the accuracy standards of the
CM2201 and the RTD.
Note: Ensure you refer to the correct RTD table for the type
of RTD you are using.
16
CM-2201 Troubleshooting
2. Temperature Verification Continued
To verify the Controller:
TURN THE POWER TO THE CONTROLLER OFF BEFORE
PROCEEDING!
a) Disconnect the RTD wiring from the input terminals.
b) Connect a 100 Ω resistor across the source or sense
terminal and common. Insert a jumper between the
source and sense terminals.
c) Apply power to the controller. The indicated or displayed
temperature should be about 32°F (0°C), depending on
the actual resistance of the test resistor if RTD TYPE is
set to 100Ω Platinum. Any resistor may have a +/- 10%
tolerance.
3. Unstable Temperature
An erratic indication of temperature can be caused by
several factors external to the controller. The controller’s
accuracy and resolution will result in an indicated
temperature change of a couple of degrees if the measured
resistance temperature falls between two discrete values
(this is sometimes referred to as quantization error).
If the instability is excessive, check:
3. Unstable Temperature Continued
d) Check, one by one, if the all RTD leads are connected to
the connector.
e) Lastly, it is possible for the RTD itself to fail on an
intermittent basis but this failure mode should be
considered unusual. This kind of failure is probably the
most difficult to find, but fortunately, it is also the least
likely as a failure mechanism.
9.2 Ground Fault
Ground fault warning/alarms can be due to incorrect
installation as well as leakage resulting from wet system
components or faulted cables.
The CM2201 Controller detects ground faults by summing
the outgoing and return trace currents through an internal
current transformer. Under normal operating conditions (no
ground fault condition), this current will be zero. When there
is a flow of current from one of the trace supply wires to
ground, a ground fault condition occurs.
If a ground fault alarm is present on start-up of a new
installation, it is likely due to a wiring error or damaged
cable. To verify this condition:
a) Wire used for extension of the RTD should be three-wire,
twisted and shielded with the shield grounded at the
controller only. Each of the three lead wires must be of
the same gauge.
b) The ideal installation has a separate conduit for the
RTD leads (if they have been extended).It is not usually
a problem to run low signal levels in the same conduit
as the power leads even in high power applications, as
long as the RTD wire is a twisted, shielded type with an
insulation rating equal to or greater than the highest
voltage in the conduit. Follow the proper Electrical Code
requirements for your particular installation.
c) Check the specifications for the particular cable
being used to ensure that it does not have excessive
capacitance when used in long lengths. This can cause a
temperature offset between what the controller reads and
what the RTD actually measures. This again is normally
not a problem since the controller compensates for all
but the worst cases of this.
a) Check that the heating circuit neutrals return to
the controller and are not connected directly to the
distribution panel. This can be a common problem if the
installation is a retrofit situation.
b) On paralleled circuits, be certain that ALL neutrals
return. The late addition of a circuit may not be obvious
Note: The controller monitors the integrity of the ground
fault (GF) detection. If a fault is detected, the controller will
generate a GFI warning/alarm, depending on the settings.
9.3 Common Warnings/Alarms - What to Look for
The CM-2201 has a wide range of warning and alarming
features that may be selectively enabled or disabled to
allow the monitoring and indication of trouble conditions.
Described below are the different warning and alarm
conditions available on the CM2201, their meanings, and
possible causes. The warning settings must be below alarm
settings. If an alarm is activated, the two low power SSRs
will be activated.
This warning/alarm appears when the temperature exceeds
the HIGH RTD WARNING/ALARM temperature setting.
Cause of Warning/Alarm:
• Warning/Alarm temperature setting too close to maintain
temperature
• Flow of hot product
• Steaming out lines
• Incorrect tracer wiring
9.3.2 Low RTD 1/ RTD 2 Temperature Reading
This warning/alarm appears when the temperature
decreases below the LOW RTD WARNING/ALARM temperature
setting.
Cause of Warning/Alarm:
• Warning/Alarm temperature setting too close to maintain
temperature
• Flow of cold product
• Empty pipe
• Damaged, wet, or missing insulation
• Heating cable not sized properly for the application
9.3.3 RTD 1/ RTD 2 Failure
This alarm indicates a sensor is not operating properly. The
temperature sensor may fail due to an “open” or “shorted”
condition.
Cause of Alarm:
• Incorrect or damaged eld wiring - open leads or excess
resistance (either intermittent or continuous) may be due
to broken or damaged wires or loose terminals.
• Damaged or inoperative temperature sensors
9.3.4 High Current Warning/Alarm
This warning/alarm activates when current levels are
greater than the HIGH CURRENT WARNING/ALARM setting
for the application.
9.3.4 High Current Warning/Alarm Continued
Cause of Warning/Alarm:
• Warning/Alarm setting too close to normal operating
current
• High in-rush current from “cold start” of self regulating
cable
• Damaged or partially shorted heating cable
• “As built” cable length is greater than design value
9.3.5 Low Current Warning/Alarm
This alarms current levels which are less than the LOW
CURRENT WARNING/ALARM setting.
Cause of Warnings/Alarm:
• Warning/Alarm setting too close to normal operating
current
• Low source voltage
• Damaged or inoperative heating cable
• Open connection—wiring problem
• SSR or contactor failed open
9.3.6 High GFI Warning
This warns that ground fault current levels are greater than
the HIGH GFI WARNING setting.
Cause of Warning:
• Warning setting too close to normal leakage current
• Moisture provides conductive ground path, which allows
ground fault current
9.3.7 GFI Alarm
This value sets the upper limit of allowable ground fault
leakage. Exceeding this limit will result in the output switch
being latched off, and the alarm activated to indicate a
ground fault condition.
• Moisture provides conductive ground path, which allows
ground fault current
9.3.8 High Voltage Warning/Alarm
This warning/alarms voltage levels that are greater than the
HIGH VOLTAGE WARNING/ALARM setting.
Cause of Warning/Alarm:
Warning/Alarm setting too close to normal operating voltage
•
• Incorrect wiring
• Power surge
9.3.9 Low Voltage Warning/Alarm
This warns/alarms of voltage levels that are less than the
LOW VOLTAGE WARNING/ALARM setting.
Cause of Warning/Alarm:
• Warning/Alarm setting too close to normal operating
voltage
• Damaged power cable
• Incorrect VOLTAGE TURNS RATIO
• “Brown-out” conditions
• Loss of power to the circuit
9.3.11 Switch Failure
This alarm indicates that the controller senses current flow
when the output switch should be off.
Cause of Alarm
• Some other device energized heat trace
• Output switch has failed “closed”
9.3.12 Power Limiting (Current Limiting)
This alarm indicates that the solid state relay is limiting the
average amount of power that is applied to the trace circuit
as defined by the MAXIMUM POWER setting.
Cause of Alarm:
• Power applied to trace circuit is being limited to the
MAXIMUM POWER setting
9.3.13 EEPROM Data Failure
This alarm indicates that the controller has detected a
failure in its non-volatile memory (this is where all of the
controller’s configuration and calibration settings are
stored). This indicates an internal problem, and the CM2201
should be replaced and returned to the factory for repair.
Cause of Alarm:
• The CM-2201 cannot bypass the failed area of its memory
and has loaded factory defaults into this failed area.
9.3.10 Overcurrent Trip
If the controller is unable to start the cable due to high
current, or after attempting to soft-start it, the controller
will trip its output switch off.
The CM-2201 should be regularly maintained as follows:
a) Check fit of door gasket and adjust as required. Clean
door gasket.
b) Verify that moisture is not entering enclosure; repair as
required.
c) Check terminals to ensure connections are secure.
d) Check wiring for any signs of overheating.
e) Clean front panel with mild soap on damp cloth.
Do not use any cloth from synthetic material or similar.
During the cleaning process, the front label may charge
electrostatically, and touching the front panel may generate
sparks.
2. Install Jumper at JP1 (120 OHM Resistor) on both terminals if CM-2201 is last device on network. Else install jumper on one terminal only of JP1.
3. If “Force “ feature is activated by external “dry contact”, use “+5V” and “IN” terminals; Ground connection is not required. If activated by external voltage signal, use
“IN” and “G” (Ground) terminals as noted.
Nelson Heat Trace Products
LIMITED WARRANTY AND LIABILITY
Appleton Grp LLC - d/b/a Appleton Group warrants that if there are any
defects in material or workmanship in any heating cable or accessory
during the first year after the date of purchase, we will provide new
products to replace any defective items, or we will refund the purchase
price paid for the accessory or cable, not including any labor or other
installation costs. As an alternate, we may elect to repair the cable or
accessory at our factory with all shipping and other removal costs borne
by the purchaser.
We further warrant that, for a period of twelve (12) months after the
date of performance, any services performed hereunder will be in a
good and skillful manner, based on our understanding of pertinent
technical data as of the date of performance of such services. Appleton
Group’s sole responsibility and liability in the event of any defect, error,
omission, or failure in the services rendered hereunder shall be to
provide corrected services of the type provided for herein, designed to
correct such defect, error, omissions, or failure, and in no event shall
Appleton Group’s liability with respect to such warranty exceed the
amount received by it from the Buyer on account of such services.
Our obligation to provide corrected services, new products, refund the
purchase price, or perform the repair described above is conditioned
upon (a) the installation of the accessory or cable conforming to the
directions set forth in our installation instructions and (b) the accessory
or cable not having been damaged by mechanical or electrical activities
unrelated to the operation of the accessory or cable.
A refund of your purchase price, provision of replacement products,
repair of the accessory or cable or provision of corrected services as
described above, shall be your sole and exclusive remedy for a breach
of this warranty. THESE ARE THE SOLE AND EXCLUSIVE WARRANTIES
GIVEN BY APPLETON GROUP WITH RESPECT TO THE GOODS AND
SERVICES AND ARE IN LIEU OF AND EXCLUDE ALL OTHER WARRANTIES,
EXPRESS OR IMPLIED, ARISING BY OPERATION OF LAW OR OTHERWISE,
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SPECIFICALLY DESIGNED AND/OR MANUFACTURED BY NELSON FOR YOUR
USE OR PURPOSE.
This warranty does not extend to any losses or damages due to
misuse, accident, abuse, neglect, normal wear and tear, negligence,
unauthorized modification or alteration, use beyond rated capacity, or
improper installation, maintenance or application. To the extent that you
or your agents have supplied specifications, information, representation
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If within thirty (30) days after your discovery of any warranty defects
within the warranty period, you notify Appleton Group thereof in writing.
Appleton Group shall, at its option, repair, correct or replace F.O.B. point
of manufacture, or refund the purchase price for, that portion of the
Goods found by Appleton Group to be defective. Failure by you to give
such written notice within the applicable time period shall be deemed
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Goods repaired or replaced during the warranty period shall be covered
by the foregoing warranty for the remainder of the original warranty
period or ninety (90) days from the date of shipment of the repaired or
replaced goods, whichever is longer.
This limited warranty does not cover any costs relating to the repair
or replacement of any accessory or cable at the installation site. Our
accessories and cables are not easily accessible. A failed accessory
or cable usually cannot be easily repaired. Replacement of a failed
accessory or cable will require that the materials under which it is
installed be removed to permit replacement of the accessory or cable.
We will not reimburse any costs relating to the repair or replacement of
any accessory or cable at the installation site.
IN NO EVENT, REGARDLESS OF THE FORM OF THE CLAIM OR CAUSE OF
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THAT WE SHALL NOT BE LIABLE TO YOU OR YOUR CUSTOMERS FOR ANY
INCIDENTAL, SPECIAL OR CONSEQUENTIAL OR PUNITIVE DAMAGES. No
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To obtain new products, arrange repair of existing product, or a refund
under this warranty, please contact Appleton Group (800-621-1506)
with a description of the defect and proof of purchase at the address
noted herein.
Appleton Grp LLC - d/b/a Appleton Group
9377 W. Higgins Rd.
Rosemont, IL 60018