Emerson NELSON HEAT TRACE CM-2201 User manual

NELSON
™
CM-2201/CM-2202
HEAT TRACE CONTROLLERS
Installation and Operating Instructions

Contents
CM-2201/CM-2202
©2017 Nelson Heat Tracing Systems
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GA2497 Rev.5
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1.0 Introduction 4
1.1GettingStarted
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 8
5.2 Display
5.3 Keypad
5.4 LED Functions
5.5 Monitoring
5.6 Alarm Management
5.7 Current-Limiting Feature
5.8 GroundFaults
5.9 Soft Start Feature
6.0 Control Modes 11
6.1 On-Off Control
6.2 Proportional Control
6.3 Forced Control Feature
7.0 Programming 12
7.1 Setpoints
7.2 Heater Setup
7.3 System Setup
8.0 Communications 18
9.0 Troubleshooting 20
10.0 Maintenance 24

CM-2201/CM-2202
Contents
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GA2497 Rev.5
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Appendix A – Specifications 25
Appendix B – Wiring Diagrams 26
Appendix C – Typical Installation Diagram 28
Appendix D – Modbus Parameters 29
Appendix E – RTD Tables 39
Appendix F – Warranty 48

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Introduction CM-2201/CM-2202
1.1 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.
The CM-2202 can monitor/control two heating circuits in
those same locations.
This manual provides information pertaining to the Installation,
operation, testing, communications and maintenance of these
controllers. See Appendix A for detailed specifications
1.2 Getting Started
The CM-2201/CM-2202 is typically connected to external RTDs,
power or communication based on Appendix B and C. Detailed set-
up of the operating/control/monitoring program is entered
throughout the following sections.
For addition help, call Nelson Technical Support or follow the
Troubleshooting section.

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CM-2201/CM-2202 Application Information
2.0 General Application Information
The CM-2201/CM-2202 are designed to operate on input
voltages between 100 and 277 Vac and 50/60Hz. 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/CM-2202 are designed tocontrol heating
circuits bymonitoring one ortwo temperature inputsfor
each circuit via industry standard 3-wire, 100Ω, Platinum
RTDs. The twoseparateRTDs for each circuit maybe
utilized to customizethe temperature control inputs.
Several different modes are user selectable aswell as the
sensor failure operational mode.
The CM-2201 and CM-2202 can be operated in
temperatures of-40°Ft o+104°F(-40°Cto +40°C).

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InstallationandInitialSetup CM-2201/CM-2202
3.1 Installation
The CM-2201/CM-2202 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.
3.2 Selecting Installation Location
The CM-2201/CM-2202 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 becarefully considered to ensure it
is always in operating conditions consistent with
specifications. See Appendix A for additionaldetails.
3.3 Mounting
The CM-2201/CM-2202 should be mounted at a convenient
height to suit operator interaction.Conduit entriesshould
be madeinthe bottomofthe enclosureto preventdamageto
the internal electronics from moisture intrusion. Conduit
entries should be drilled and the use of suitable bushings is
required to maintain the environmental ratings.
3.4 Wiring
Electrical wiring diagrams and schematics are provided in
Appendix B andC of this manual. Ensure that all wiring
and connections are in accordance with applicable wiring
codes. Enclosure grounding must be in accordance with
applicablewiringcodes fornon-metallic devices.
The power supply for the CM-2201 isderived from the
power provided for the load. However, the power supply
forthe CM-2202 can be provided independentofthe
powersupply for the loads being controlled.For
example, the powersupply forthe CM-2202 can be120
VAC whilethe loads being controlled canbe277 VAC.
Further,the power supplyforthe CM-2202 may also be
derived from either oftheloads being controlled –thisis
implemented by connecting appropriate jumpers.
Refer to Wiring Diagram in Appendix B for details.

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4.1 Initial Set-Up
Upon initial power-up, the CM-2201/CM-2202 display will
run self-check, display the software version and then start
the main program.
4.2 Display Modes
This feature determines what messages and functions
are
displayed during normal operations. If set to “normal user” only
basic information i
sdisplayed. If set to “advanced user” all
controllerinformationis displayed. Each parameter shown in
this manual will list the Display Mode required to view
information and access each function duringprogramming.
4.3 Password Protection
The CM-2201/CM-2202 may 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 mayalsoreplace the default
password value (1234) with their own unique value for greater
protection of operational parameters.
4.4 Security Levels
CM-2201/CM-2202 has two levels of security. The high level
(Advanced Display) requires password protection. Disabling
the password from the Password Enable/Disable menu will keep
the password disabled indefinitely –any parameter can be
changed without theuse ofa password. At this level all the
functionsand monitoring parameters are open.The low
level (Normal Level) does not give accesstoparameters
settings,butis open for fewparameters monitoring like
temperature, current, GFI, etc.
If the password is“Enabled”,whengoingdirectlyto the
parameter to be changed,afterthe‘up’ or‘down’ arrowis
pressed,the controller willask for the password. Then the
parameter can be changed and saved.The password will stay
disabled for 15 min, then be automatically re-enabled. During
the15min period whenthepassword is disabled, other
parameters can be changed and saved.
CM-2201/CM-2202
InstallationandInitialSetup

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GA2497 Rev.5
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CM-2201/CM-2202 General Operation
5.1 General Operation
5.2 Display
The CM-2201/CM-2202 utilizes a 2 line x 16 character
alphanumeric displayviewable fromthe front keypad.
The toplineis reserved for the function or operation
and the bottom line displays the value range.
5.2.1 Navigation for CM2201
The CM2201 monitors one heating circuit consisting of
load (typically a heating cable) and controls theload
based on the temperature of the item being heated
(typically a pipe) as provided via one or two RTD’s
attached to the pipe and connected to the controller.
To monitor the load, press Actual until “Operating
Values” is displayed, then press Right or Left arrow to
scroll through thevarious values.
To review the statistics that have been collected,
press Actual until “Statistics” is displayed then press
Right or Left arrow to scroll through the various
statistics.
To change the control and monitoring settings
(including alarm settings), press the Program key and
then Right or Left arrowto scroll through the various
settings. Any setting can be altered by pressing the
Up or Down arrow. Note that a 4-digit password
may berequiredtochange certain settings –when
required, the cursor will flash on the left most digit –
use the Up arrow to increase this digit value or
the Down arrow to decrease it. Move the cursor to
the second leftmost digit using the Right or Left
arrow and it will flash until adjusted using Up/
Down arrows. When the last digit has been
selected, press Enter and then changes will be
allowed to the setting. Once the setting is
adjusted, press the Enter key to store it.
To view alarms, press the Alarms key and then Right
or Left arrowto scroll through the various alarms.
Alarms that are not active can be erased bypressing
the Reset key.
5.2.2 Navigation for CM2202
The CM2202 can monitor/control two separate heating
circuits (channels). The controller defaults to Channel 1
upon first start-up. All parameters for Channel 1 can
be displayed and modified using standard techniques as
described for the CM2201 inSection 5.2.1.
To changeto Channel 2, simply press the “ Actual ”
key and then right arrow –the active channel will be
displayed. To change the channel, press the Up arrow.
In general, when the active channel is displayed
(eg. "CH.2"), the channel can be changed by
pressing the Up or Down arrow.

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GA2497 Rev.5
General Operation CM-2201/CM-2202
5.3 Keypad
The keypad is “capacitive” touch sensitive and keys
are activated by simply touching the area ofthe
desired key with a finger, even when wearing gloves.
Note that a stylus or other item used to touch the
keypad will usually not activate the keys.
5.4 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 any
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 or any
circuit; the alarm LED will illuminate solid when an alarm
was previously present but is not currently active.
5.5 Monitoring
By touching the“ Actual” button follow the arrow
and the controller will scroll through all
the active parameters .
5.6 Alarm Management
All alarm(s) will be saved in the alarm log. If no
alarms are active (alarm LED solid red) the Alarm
LED can be turned off by touching “Reset” once for
every alarm that previously occurred. If any alarm is
active (alarm LED flashing red) the user cannot reset
the alarm. The two alarm relays are SSR type. To set
the contacts of the relays go to Settings –Heater
Setup –Alarm contact. By choosing up/down arrow,
the contacts can be selected to function as Normally
Open or Normally Closed. Press “Enter” to save the
selection. Note: By setting the contacts to NC,
these contacts will be open when there is no power
applied to the unit (this can be useful for signaling
loss of power to the unit) OR there is an active
alarm OR there previously was an active alarm that
has not been acknowledged.
The alarm contacts function as follows:
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 isenergized 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% ofthetime.
5.8 Ground Faults
Ground faults typically are the result of damaged or
improperlyinstalledcableswhichallowcurrent-
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 thecable and/or the pipe itself. This
type of fault can eventually become serious, resulting
in overheating/fire/shock hazards. Current leakage to
ground can bemonitored by electronic circuitryand
the SPC can be programmed to either alarm or trip
when leakage c u r r e n t e x ce e d s t h e s p e c i f i e d
m a x i mu m a l l o wa b l e a m o u n t .

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The Soft-Start feature enables self-regulating cables to be
energized at low temperatures without causing excessive load
on the electrical system and extending cable life by reducing
cable internal heating due to inrush currents. The resistance
of self-regulating cables decreases as the cables get
colder, which results in higher current and can result in
breaker trips if temperatures are very cold and the
installed length of cable is long. 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.
5.9 Soft-Start Feature
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.
CM-2201/CM-2202 General Operation

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CM-2201/CM-2202
Control Modes
6.1 Control Modes
TheCM-2201/CM-2202 allows the user to select different
control modes based on their individual process control
parameters.
6.2 On-Off Control
This control method simply energizes the cable until the
actual monitored temperature rises to the set point 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. Notethat
thistype ofcontrol canresult in some temperature
“overshoot;”.Thisis because the cable isde-energized when
the monitored temperature reaches the upper limit. However,
theresidual 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.”
6.3 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 set point value and the actual monitored
temperature increases, theamount oftime the cableis
energized increases proportionately. This helps reducethe
“overshoot”and“undershoot”commonly associated with
On/Off control.
6.4 Forced Control Feature
This control method simply allows the user to force the
cable on or off as desired using an external signal (eg +5
VDC or 24 VAC) applied to the IN and G terminals or an
external dry contact across the +5V and IN terminals.
The External Disable must be set to “ON” to allow for
external control, at which point the controller operates
as follows:
A) If the Temperature setpoint is “OFF” or “None”,
then the heater gets energized by applying the
external signal or closing the external contact.
B) If the Temperature setpoint is a specific value
(eg 55C), then the setpoint will be maintained as
per normal operation ONLY when the external
signal is present or the external contact is closed
–otherwise, the heater will be disabled.

CM-2201/CM-2202
Programming
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GA2497 Rev.5
7.1 Programming
7.2 Program-Setpoints
7.2.1 Setpoint Value
This message displays the name of the sub-menu when
entered.
1. DisplayMode:All
2. Range: N/A
3. Default:N/A
7.2.2 Maintain Temp
This value sets the control setpoint temperature for all
operating modes.For On-Offcontrol,the circuit is
energized ifthecontrol temperature is less than the
maintain temperature minus the deadband. The circuitis
de-energized if the control temperature is greater than
the maintain temperature plus thedeadband. Ifmaintain
temp isset toNone then theheater 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. DisplayMode:All
2. Range: -50 to 500°C, none or -58°F to 932°F,
none, Off
3. Default:10°or 50°F
7.2.3 Low Temp Alarm
This value sets the Low TemperatureAlarm 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 RTDA 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. DisplayMode:All
2. Range: -50C to Maintain Temperature,Off, -58°F to
Maintain Temperature, Off
3. Default:5°Cor 41°F
4. Restrictions: Message does not exist if Maintain
Temperature issetto Off.
7.2.4 High Temp Alarm
Thisvalue sets the High Temperature Alarm setpoint.
Itmust begreater than the maintain temperature plus
deadband. To disablethis alarm set the value to “Off”.
When the measured temperature ofeither RTDA orRTDB (if
activated) isgreater than orequal to this set point, the High
TemperatureAlarm is activated and a “HIGH TEMP ALARM”
message is added to the alarm stack. The alarm deactivates
when the temperature falls below this alarm set point.
1. DisplayMode:All
2. Range: Maintain Temperatureto +500°C, Off,
Maintain Temperature to +932°F, Off
3. Default: Off
4. Restrictions: Message does not exist if Maintain
Temperature issetto Off.
7.2.5 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 theHeater
Currentrisesabovethisalarmsetpoint.Note: This set point
is based on the heater at 100% power. If Proportional
ControlorCurrentLimitingisenabled,all current
measurements will be scaled to 100% power, based on a
constant resistive load, before being compared to the alarm
setpoint.
1. DisplayMode:All
2. Range: 0.1A to High Current Alarm, Off
3. Default: Off
7.2.6 High Current Alarm
Thisvalue sets the High Current Alarm setpoint. Itmust be
greater than the low current alarm setpoint. To disable this
alarmsetthe value to“Off’.When theheatercurrent is
greaterthanorequaltothissetpoint, theHighCurrent Alarm
is activated and a “HIGH CURRENT ALARM” message is
addedtothealarm stack.Thealarm deactivates when the
heatercurrentfallsbelowthisalarmset point.This setpoint
is based on the heater at 100% power.

Programming
CM-2201/CM-2202
7.1.6 High Current Alarm Continued
If Proportional Control or Current Limitingis enabled, all
current measurements will be scaled to 100% power, based
on aconstant resistive load, before being compared to the
alarm setpoint.
1. DisplayMode:All
2. Range:LowCurrentAlarm 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. Todisable 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. DisplayMode:All
2. Range: 10 to Ground Fault Trip, Off
3. Default: 30mA
7.1.8 Ground Fault Trip
This value sets the Ground Fault Tripsetpoint. 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 isgreater than orequal to this setpoint, the
heater circuit isde-energized,theGroundFaultTripAlarm
is activated and a “GROUND FAULT TRIP”message is added
to the alarm stack.This is a latching alarm and trip.
When the cause ofthealarm has been corrected, the
circuit may be energized by the manual reset function.
1. DisplayMode: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 Voltageis 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
Voltagerises above this alarm setpoint.
Low Voltage Alarm Continued
1. DisplayMode: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 theLowVoltageAlarm setpoint.To
disable this alarm set the value to “Off’. When the Heater
Voltage is greater than or equal to this setpoint, the High
VoltageAlarm is activated and a “HIGH VOLTAGEALARM”
message is added to the alarm stack messages. The
alarm deactivates when the Heater Voltage drops below
this alarm setpoint.
1. DisplayMode:All
2. Range: Low VoltageAlarm to 280VAC, Off
3. Default: Off
7.2 Program- Heater Setup
7.2.1 Heater Setup
This message displays the name of the sub-menu when
entered.
1. DisplayMode:Advanced
2. Range: N/A
3. Default:N/A
7.2.2 Enable Heater
Thisselectionenables control and monitoringoftheheater
circuit. Setpoints and measured value messages cannot be
accessed unless the heater is enabled. Select “No” if the
circuit is not used.
1. DisplayMode:All
2. Range:yes,no
3. Default: yes
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CM-2201/CM-2202
Programming
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GA2497 Rev.5
7.2.3 Heater ID
This selection allows for user defined Heater Identification.
It provides aunique, 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[SELECTUP/DOWN]arrow keys to change
thecharacter.Move to the nextcharacter by pressing [NEXT]
arrow. Press [ENTER] in the last character position to save the
Heater ID.
1. DisplayMode:Advanced
2. Range: 20 Characters
3. Default: Blank
7.2.4 Manual Override
This selection sets theresponse ofthe heater circuit tothe
Override inputs. The Override inputs respond to contact closure.
If the Over rideisset to“Off”,theover ride inputs are ignored
and control of the heater circuit operates normally based onthe
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 thecontact on the Override
inputis closed,the heater controlresumes innormal manner.
1. DisplayMode:Advanced
2. Range:On,Off
3. Default: Off
7.2.5 Deadband
TheDeadband isdefinedasthedifference 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 butalso increases theheater switching frequency.
1. DisplayMode:Advanced
2. Range:1C°to5C°,1F°to10F°
3. Default:2C°or5F°
4. Note:Deadbandis disabled forProportionalControl
mode.
Control Type
This selection determines the type of control method
used by the controller, either On-Off (Deadband) or
Proportional Control.TheOn-Offcontrolmodeisavailable
forall 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
theconstantly changing characteristics ofself-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.
5. DisplayMode:Advanced
6. Range: On-Off, Proportional
7. Default: On-Off
8.
Selection does not exist if Maintain Temperature is set
to Off.
7.2.6 Current Limiting
This selection sets the maximum average current limit
allowed for the heater circuit. Itis useful for reducing the
power output ofconstant wattage heaters. The load will be
turned on for a period of time and then turned off for a
periodof time to maintain theaverage current draw to the
value set.
1. DisplayMode:Advanced
2. Range: 0.5 to 30.0 A, Off
3. Default: Off
4. Note: The valuerange is in 0.5A increments.
7.2.7 Soft Start Mode
This function ramps the heater output from Off tonominal
current of the heater over the set soft start cycle time. It
is useful for reducing inrush currents of self-regulating
heaters. Atthe end of the soft start cycle time, theload will
no longerbe controlled by the softstart function.
1. Display: Advanced
2. Range: 10 to 999 seconds, Off
3. Default: Off
14

Programming
CM-2201/CM-2202
7.2.8 Auto Test Cycle
This value sets the frequency at which the Auto Test Cycle is
activated. Auto Testisafeature that exercises the system by
automatically applying power to the heater at specified
time intervals. If analarm condition is detected during this
period the Auto TestAlarm 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 messsage in the Alarm Menu and press
[ENTER]. To disable this feature, set the value to “Off”.
The AutoTestCycle does notoperate ifheaterisforcedoff for
any reason, including ground fault trip.
Auto Testdecreases maintenance by providing an early
warning ofproblems that would otherwise go undetected
until the heater was needed.
1. DisplayMode:Advanced
2. Range: 1 to 720 hours, Off
3. Default: 24 hours
7.2.9 RTD Operation
This selection determines how the control temperature is
utilizedby 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.
InAverage Mode, the controltemperature is based onthe
averageof RTD-A and RTD-B measured temperatures.
InLowestMode,controltemperatureisbased 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
basedon RTD-A,but ifthe 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.
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:OneRTD,Backup,Average,Lowest,Highest,
High Temperature Cutoff
3. Default: One RTD
4. Restrictions: Message does not exist if Maintain
Temperature is set to Off.
7.2.10 RTD Failure Mode
This selection setsthe controllersfail-safemode.The
controller detects if RTD-A has failed and will use RTD-B if
available.IfRTD-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 isapotential hazard from
overheating, you may select “Off”, to de-energize the circuit
until one ofthe RTD’sbecomesavailable.
1. DisplayMode:Advanced
2. Range:On,Off
3. Default: Off
4. Restrictions: Message does not exist if Maintain
Temperature is set to Off.
7.3 Program– System Setup
7.3.1 System Setup
This message displays the name of the sub-menu when
entered.
1. DisplayMode: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 “disable”
if program access is currently enabled and show “enable” if
program access is currently disabled.
1. DisplayMode:All
2. Range: Enable or Disable
3. Default: Enable
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©2017 Nelson Heat Tracing Systems
www.nelsonheaters.com GA2497 Rev.5

CM-2201/CM-2202
Programming
©2017 Nelson Heat Tracing Systems
www.nelsonheaters.com
GA2497 Rev.5
7.3.3 Change Password
This selection allows the user to change the default password.
The user isprompt toenter the old password, press [ENTER].
Ifverified,theuser is then to enter the new password, press
[ENTER). The user is prompt to re-enter the new password.
Bynot entering a password and pressing [ENTER], the
controller assumes nopassword.
1. DisplayMode:Advance
2. Range:Any combination of2to16characters0–9,
A–Z.
3. Default:1234
7.3.7 Default Display
This function specifiesthe informationthat will be
displayed when no key has been pressed for the Display
Time out interval as described below.
VALUE
INFORMATION
System status
Heaterstatus
Heater temp
DISPLAYED
Alarm status of all the
heaters
Alarm status of the
heater
Temperature of the heater
7.3.4 Units
This selection determines the unit of measure for
temperature values. All temperatures are displayed in the
selected units ofeither Celsius degrees (C°) orFahrenheit
degrees (F°).
1. DisplayMode:Advance
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. DisplayMode:Advance
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. DisplayMode:All
2. Range:Normal,Advance
3. Default: Advance
DisplayMode:Advance
1. Range:System Status, Heater Status, Heater Temp
2. Default: system status
3.
Restrictions: Temperature messages are not displayed
if Maintain Temperatureis 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. DisplayMode:Advance
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 Section8.0for completeinformationon
Modbus communications.
1. DisplayMode:Advance
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
operateon the same baudrate.
1.Display Mode:Advance
2.Range:1200,2400,4800,9600,19200
3. Default: 9600
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Programming
CM-2201/CM-2202
7.3.11 Reset Module
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. DisplayMode:Advance
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. DisplayMode:Advanced
2. Range: N/A
3. Default:N/A
7.4.2 Alarm Output Test
This function is used for testing and commissioning
purposes allowing thealarm output tobeforced Oneither for
ashortperiodoftimeorcontinuously.Attheendofthe
specified time duration, the testing option is automatically
disabled. The alarm testfunction will not operate ifthe
alarm configuration is set to disable and the message
“ALARMDISABLED”will appear.
1. DisplayMode:Advanced
2. Range: 1-24 hours, Disabled, Continuously
3. Default: disabled
7.4.3 Heater Test
This function overrides heater control for maintenance
purposes.Fornormaloperation,set to “disable”. If a period
of time is selected, the heater is forced On or Off for the
selectedinterval. If “continuous” is selected the heater is
forced On or Offuntil “disable" is selected.
1. DisplayMode:Advanced
2. Range: 1-24 hours, Disabled, On Continuously
3. Default: disabled
Ground Fault Test
This function will test the ground fault trip function of the
controller toensure 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 capa- ble 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.
4. DisplayMode:Advanced
5. Range:Autotestcycle,Now,Disabled
6. Default: Disabled
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©2017 Nelson Heat Tracing Systems
www.nelsonheaters.com GA2497 Rev.5

©2017 Nelson Heat Tracing Systems
www.nelsonheaters.com
GA2497 Rev.5
CM-2201/CM-2202 Communications
8.0 Communications
The Nelson Heat Trace CM-2201 supports a subset of the
Modbus
®
RTUprotocol format that providesmonitoring,
programming, and control functions using Read (03) and
Write(05-06)register commands.
8.1 General Information
Serial Port:
Baud Rate:
Selecttheserial portthat
corresponds to your RS-485
adapter. USB to Serial adapter
may be used for devices without
serial connections.
User Defined at 1200, 2400,
4800,9600 or 19200
Data Bits: 8
Stop Bits:
Parity:
Device Address:
1
None
User Defined between 1 and 255
8.2 Modbus Registers
For all Modbus registers, see Appendix D.
Example of checking alarms via Modbus from a remote
terminal.
Controller SETTINGS and Status used on this example:
a. Modbus address 04
b. Baud rate 19200; non-parity; Stop bit 1.
c. High Temperature alarm active
1.
To check if any alarm is activated, send the
following instruction:
04 03 0046 0026 2590
04 = controller Modbus number
03 = Modbus function code 3
0046 = start reading from data address
70
0026 = the next 38 addresses
2590 = CRC
2.
The controller will answer with value 0x02 (High
Temperature Alarm) active Alarm
3.
Once the alarm condition has been resolved, the
alarm can be cleared by sending the following
instruction:
04 05 0045 FF00 9C4C
04 =controller Modbus number
05 = Modbus function code 5
0045 = writing to data address 165
FF00 = erase command
9C4C = CRC
At this point the controller enters the
alarm into the alarm log memory and
clears the active alarm. To check the
alarm log memory, see below.
4.
If the command to check if any alarm is
activated (as shown in (1) above) is now sent to
the controller, and assuming no other alarms
have since been activated, the controller will
answer with 0x0000 (no active alarms).
5.
To check the alarm log memory, issue the
following instructions:
04 03 006E 0026 A598
04 = controller Modbus number
03 = Modbus function code 3
006E = start reading from data address
110
0026 = the next 38 addresses
A598 = CRC
6.
The High Temperature Alarm will be listed here,
so the controller will answer 0x02. The Alarm
log can hold 20 alarms. After 20 alarms the
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©2017 Nelson Heat Tracing Systems
www.nelsonheaters.com
GA2497 Rev.5
oldest alarm will be erased to allow for storage of
the new alarm. To erase all alarms on alarm log,
see below.
7.
To erase all alarms on the Alarm log from the
remote terminal, send the following instruction:
04 05 0097 FF00 3D83
04 = controller Modbus number
05 = Modbus function code
0097 = data address 151 to write FF00 =
command to erase all memory log.
3D83 = CRC
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CM-2201/CM-2202
Communications

©2017 Nelson Heat Tracing Systems
www.nelsonheaters.com
GA2497 Rev.5
CM-2201/CM-2202
Troubleshooting
9.1 Troubleshooting
9.2 Operator Checks
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 todetermine ifafaultisassociated 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 ofthenewCM2201/CM-2202.
Refer to the following sections for the appropriate topic.
9.2.1 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. Somespecific RTD problems and the correct
methods for troubleshooting are outlined as follows.
1. RTD Failure Alarm(s)
If the CM2201/CM-2202 controller indicates a failure of an
RTD:
a)
Ensure that the RTD is a 3-wire 100 (Platinum Type).
TURN THE POWER TO THE CONTROLLER OFF BEFORE
PROCEEDING!
b) DisconnecttheRTD wiringfrom theinputterminals.
c) Measure the RTD’sresistancebetweenthesource
(RED) and sense (RED) leads at the controller (it should
not exceed 40Ω). Excessive lead resistance will cause
a RTD FAILURE ALARM and must be corrected. Look for
loose terminals, excessive lead length, or insufficient wire
gauge and correct as necessary.
d)
Measures the RTD’sresistancebetweenthesource
(RED) or sense (RED) lead and the common (WHT) lead
of the RTD at the controller (should be between 60
and 330Ω depending on the temperature and the lead
resistance. Verify that the RTD is wired correctly —the
heat tracing conrtrollers will always be terminated in
the order: source (RED), common(WHT), sense (RED).
When wiring to theCM2201/CM2202, the terminals are marked
as follows:
Terminal No.
Description
GNDBus
Shield
RA
RTD A Source (RED)
WA
RTDA Common (WHT)
RA
RTDASense(RED)
GNDBus
Shield
RB
RTD B Source (RED)
WB
RTDBCommon(WHT)
RB
RTD B 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-White-Red
triad color code for the RTD connections. Usually, the RED
lead is the common connection (same as the White-White-
Redcolorscheme)and theWhiteandBlack connectionsmay
beusedinterchangeably.
2. Temperature Verification
Ifyou consider that the indicated ordisplayedtemperature
isnot correct,thecontrollerandtheRTDcanbequickly
checked forcorrectoperation.To verify the RTD:
TURN THE POWER TO THE CONTROLLER OFF BEFORE
PROCEEDING!
a) DisconnecttheRTD wiringfrom theinputterminals.
b) To calculate the temperature indicated by the RTD,
measure the resistance from source (red wire) or sense
(redwire)to common(whitewire)andsubtract the
resistance measured between source and sense.This
will give acompensated resistance value that can be
cross- referenced to one of the RTD tables found in
Appendix EorAppendixF. Compare the measured
resistanceand 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/CM2202 and the RTD.
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