Nelson CM-2201 User manual

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

Table of Contents CM-2201/CM-2202
©2018 Nelson Heat Tracing Systems www.nelsonheaters.com GA2497 Rev.6
1.0 Introduction 4
1.1 GettingStarted
2.0 General Application Information 4
3.0 Installation 5
3.1 Selecting Installation Location
3.2 Mounting
3.3 Wiring
4.0 Initial Set-up 5
4.1 DisplayModes
4.2 Password Protection
4.3 Security Levels
5.0 General Operation 6
5.1 Display
5.2 Keypad
5.3 LED Functions
5.4 Monitoring
5.5 Alarm Management
5.6 Current-Limiting Feature
5.7 GroundFaults
5.8 Soft Start Feature
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 SystemSetup
8.0 Communications 15

CM-2201/CM-2202 Table of Contents
©2018 Nelson Heat Tracing Systems www.nelsonheaters.com GA2497 Rev.6
9.0 T roubleshooting 16
9.1 Operator Checks
9.2 Ground Faults
9.3 RTDs
9.4 Common Warnings/Alarms
10.0 Maintenance 20
AppendixA – Specifications 21
AppendixB –WiringDiagrams 22
AppendixC–TypicalInstallationDiagram 24
AppendixD– Mounting Details 25
AppendixE– ModbusAddress List 26
AppendixF–ASCIITable 38
AppendixG – RTD Tables 39
Appendix H – Warranty 48

Introduction CM-2201/CM-2202
©2018 Nelson Heat Tracing Systems www.nelsonheaters.com GA2497 Rev.6
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1.0 Introduction
The Nelson Heat Trace CM-2201 is designed to monitor and
controloneheatingcircuitinordinaryandClassI,Division 2,
ClassI,Zone2,andZone2 hazardous locations.
The CM-2202 can monitor/control two heating circuits in
those same locations.
This manualprovidesinformationpertainingtothe
installation,operation,testing,communicationsand
maintenance of these controllers.SeeAppendixAfor
detailedspecifications
1.1 Getting Started
TheCM-2201/CM-2202istypicallyconnected to external
RTDs, power orcommunicationbasedonAppendixBand
C.Detailedset-upoftheoperating/control/monitoring
programis entered throughout the following sections.
Foradditionhelp,callNelsontechnicalsupportorfollow the
Troubleshootingsection.
General Application Information CM-2201/CM-2202
2.0 General Application Information
The CM-2201/CM-2202aredesignedtooperateoninput
voltages between100and277Vacand50/60Hz. Load
switching is handledby a2-Pole solid-state relay and can
control resistive loads of 30A continuous @40°C
ambient.
TheCM-2201/CM-2202aredesignedtocontrolheating
circuits bymonitoringoneortwotemperature inputsfor
each circuitviaindustry standard3-wire,100Ω, Platinum
RTDs.The twoseparateRTDsfor each
circuit maybe
utilized to customize the temperature control inputs.
Severaldifferentmodesareuser
selectableaswellasthe
sensorfailureoperational
mode.
TheCM-2201andCM-2202can beoperatedin
temperaturesof-40°Fto+104°F(-40°Cto+40°C) .

CM-2201/CM-2202 Installation and Initial Setup
©2018 Nelson Heat Tracing Systems www.nelsonheaters.com GA2497 Rev.6
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3.0 Installation
The CM-2201/CM-2202 must be installed only in areas for
which it has been approved and in accordance with all
applicable electricalcodesandordinances. Allconduit entry
holes mustbeappropriatelyinstalledandsealedto
maintain
ingress protection rating.
Donot installthisunitprior to functional testingif shipping
container or internalpackagingshows signs of damage.
Notifytheappropriateindividualsimmediatelyifdamageis
suspected.
3.1 Selecting Installation Location
TheCM-2201/CM-2202should beinstalledinan area
protected from the elements as much as possible. It is
possible to installthe unit in unprotected areas but such
often limits maintenance/access. Further, installation in
unprotected areasmustbecarefullyconsideredtoensure it
isalways inoperatingconditionsconsistentwith
specifications. See AppendixAforadditionaldetails.
3.2 Mounting
TheCM-2201/CM-2202shouldbemountedat a convenient
heightto suit operator interaction.
(See Appendix D for mounting details.)
Conduit entriesshouldbe madeinthebottomofthe
enclosureto
preventdamagetothe 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
Electricalwiring diagramsandschematicsareprovidedin
AppendixB andC of this manual.Ensure that all wiring
andconnectionsareinaccordancewithapplicablewiring
codes. Enclosuregroundingmustbein accordancewith
applicablewiringcodes for non-metallic devices.
ThepowersupplyfortheCM-2201isderivedfromthe
power provided for the load. However, the power supply for
theCM-2202canbeprovidedindependentofthe
power
supplyfortheloadsbeingcontrolled.For
example,the
powersupplyfortheCM-2202canbe120 VACwhilethe
loadsbeingcontrolledcanbe277VAC.
Further,thepower
supplyfortheCM-2202mayalsobe
derivedfromeitherof
theloadsbeingcontrolled–thisis
implemented by
connecting appropriate jumpers.
4.0 InitialSet-Up
Upon initial power-up, the CM-2201/CM-2202 display will
runself-check,displaythesoftwareversionandthenstart
the main program. Default settings are set to disable
heating cables, (See 7.0 Programming to enable heaters
and program set points.)
4.1 Display Modes
Thisfeaturedetermineswhat messagesandfunctions
aredisplayedduringnormaloperations.Ifsetto“normal
user,”onlybasicinformationisdisplayed.Ifsetto
“advanced user,”allcontrollerinformationisdisplayed.
Each parameter shown in this manual will list the Display
Moderequiredtoviewinformationandaccesseachfunction
during programming.
4.2 Password Protection
TheCM-2201/CM-2202may havepasswordprotection
enabledto ensurethatsensitiveoperatingparametersare
not inadvertently adjusted. If password protection is
enabled,the userwillbepromptedtoenteravalidvalueto
access any protected features. Theusermayalsoreplace
thedefault passwordvalue(1234)withtheirownunique
value for greater protection of operational parameters.
4.3 Security Levels
CM-2201/CM-2202hastwolevelsofsecurity.Thehigh
level
(AdvancedDisplay)requires passwordprotection.
Disabling
the password from the Password Enable/Disable
menu will
keep the password disabled indefinitely – any
parameter can
bechangedwithouttheuseofapassword.
At this level all
thefunctionsand monitoring parameters
are open.
The low level(NormalLevel)does not giveaccessto
parameters settings,but certainparameters(suchas
:
temperature, current,GFI, etc.) are open for monitoring.
Ifthepassword is“Enabled”,goingdirectlytothe
parameter to be changed,and pressing the ‘up’or‘down’
arrow, will cause thecontroller to askforthepassword. If
correctly entered then
theparametercanbechangedand
saved.Thepasswordwill
stay disabled for 15 min, then be
automatically re-enabled. When disabled the password does
not need to be entered to change and save parameters.

General Operation CM-2201/CM-2202
©2018 Nelson Heat Tracing Systems www.nelsonheaters.com GA2497 Rev.6
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5.1 Display
TheCM-2201/CM-2202utilizes a 2-line x 16-character
alphanumeric displayviewablefromthefrontkeypad. Thetop
lineis reserved for the function or operation and the
bottom line displaysthevaluerange.
5.1.1 Navigation for CM2201
TheCM2201monitorsoneheatingcircuitconsistingof load
(typicallyaheatingcable)andcontrolstheload
basedonthe
temperatureoftheitembeingheated
(typicallyapipe)as
providedviaoneortwoRTD’s
attachedtothepipeand
connectedtothecontroller.
Tomonitortheload,press
Actual until“Operating Values”isdisplayed,thenpress
Right or Left arrowto scrollthroughthevariousvalues.
Toreviewthestatisticsthathavebeencollected,press Actual
until“Statistics”isdisplayedthenpress Right or Left arrowto
scrollthroughthevariousstatistics.
To change the control and monitoring settings (including
alarm settings), press the
Program key and then Right or
Left arrowtoscrollthroughthevarious settings. Any
settingcanbealteredbypressingthe
Up or Down arrow.
Notethata4-digitpasswordmay
berequiredtochange
certainsettings–when
required,thecursorwillflashonthe
leftmostdigit–
usethe Up arrowtoincreasethisdigitvalue
orthe
Down arrowtodecreaseit. Movethecursortothe
secondleftmostdigitusingthe Right or Left arrow andit
willflashuntiladjustedusing
Up/Down
arrows. Whenthelastdigithasbeenselected,press Enter
andthenchangeswillbeallowedtothe setting. Oncethe
settingisadjusted,pressthe
Enter keytostoreit.
Toviewalarms,pressthe Alarms keyandthen Right or
Left arrowtoscrollthroughthevarious alarms. Alarms
thatarenotactivecanbeerased
bypressingthe Reset
key.
5.1.2 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 in Section 5.2.1.
To change to 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 (e.g.
"CH.2"), the channel can be changed by pressing the
Up or Down arrow.

CM-2201/CM-2202 General Operation
©2018 Nelson Heat Tracing Systems www.nelsonheaters.com GA2497 Rev.6
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5.2 Keypad
The keypad is “capacitive” touch sensitive and keys are
activated by simply touching the area of the 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
LEDindicatorswillshowthestatusoftherespective functions.
The power LED will be illuminated when the
controller is
connected to a source voltage.The heater LED willbe
illuminatedwhenvoltageisappliedtoanyheater. Thesystem
LED willilluminateifthereisaninternal hardwareissuewiththe
controller.ThecommLEDwill illuminatewhenthecontrolleris
sendingdatathrough external communication.The alarmLED
will flash when thereisacurrentactivealarmcondition or any
circuit; thealarmLED willilluminate solid when an alarm was
previously presentbutisnotcurrentlyactive.
5.5 Monitoring
By touching the “ Actual” button follow the arrow and
the controller will scroll through allthe 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. (See 7.2.12 for further
information on the Alarm contacts setting).
Power-Limiting Feature
The Power-Limiting feature operates similarly to the Soft-
Startinthatitrestrictstheamountoftimethecable is
energizedduringanygivenperiodtherebyreducingthe
averagecurrentdrawofthecableduringthatperiod.
For example,ifacablenormallydraws8Amps,butcurrent
limitissetto6Amps,thenthecable wouldbeenergized
only75%of the time.
5.7 Ground Faults
Groundfaultstypicallyaretheresultofdamagedor
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 resultincurrentleakagetoground throughthe
groundbraidofthecableand/orthepipeitself. Thistypeof
faultcaneventuallybecomeserious,resulting
in
overheating/fire/shock hazards. Current leakage to
ground
canbemonitoredbyelectroniccircuitryandtheSPC/DPC can
beprogrammedtoeitheralarmortripwhenleakage
current exceeds the specified maximum
allowable amount.
5.9 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 extending cable life by
reducing cable internal heating due to inrush currents. The
resistanceofself-regulatingcables 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. TheSoft-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; afterafewminutes,the cableis usuallywarm
enoughsuch that the resistance has increasedandthe
current decreased to the point where it can be continuously
energized.

Control Modes CM-2201/CM-2202
©2018 Nelson Heat Tracing Systems www.nelsonheaters.com GA2497 Rev.6
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6.0 Control Modes
TheCM-2201/CM-2202allowstheusertoselectdifferent
control modesbasedontheirindividualprocesscontrol
parameters.
6.1 On-Off Control
Thiscontrol methodsimply energizesthecableuntilthe
actual monitored temperature rises to the setpoint value
plushalf thedeadbandvalue(upper limit).Thecableis then
de-energized until the actual monitored temperature
dropsto the
setpointvalueminushalfthedeadbandvalue. Notethatthis
typeofcontrolcanresultin some temperature “overshoot;”
thisisbecausethecableisde-energized
when the monitored
temperature reaches the upper limit.
However,theresidualheat
inthecablecontinuestotransfer
tothepipe,andthiswillcause
thepipetemperatureto
increaseslightlyabovetheupperlimit.
Similarly,therecan
be some temperature “undershoot.”
6.2 Proportional Control
This control method uses the typical proportional
control algorithmwhereinthecableiscycledonandoffata
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
temperatureincreases,theamountoftimethe
cableis
energizedincreasesproportionately.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 (e.g. +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 (ex. 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
©2018 Nelson Heat Tracing Systems www.nelsonheaters.com GA2497 Rev.6
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7.1 Program-Setpoints
7.1.1 Setpoint Value
This message displays thename ofthe sub-menu when
entered.
1. DisplayMode:All
2. Range: N/A
3. Default:N/A
7.1.2 Maintain Temp
This value sets the control setpoint temperature for
alloperating modes.ForOn-Off control,the circuitis
energizedifthecontroltemperatureislessthanthe
maintaintemperatureminusthedeadband.Thecircuit
is
de-energized if the control temperature is
greater than the maintaintemperatureplusthe
deadband.Ifmaintaintemp
issettoNone thenthe
heatercircuitwillhavetemperature
monitoring with no
control temperature. If the maintain
tempissettoOff
thentheheatercircuitwillhaveno
temperature
monitoring or control.
1. DisplayMode:All
2. Range: -50to 500°C, none or -58°Fto 932°F,
none,Off
3. Default:10°or50°F
7.1.3 Low TempAlarm
ThisvaluesetstheLowTemperatureAlarmsetpoint.It must
belessthanthemaintaintemperatureminusthe
Deadband.
To disablethisalarmsetthevalueto“Off’.
When the
measured temperature of either RTDA or RTD
B (if
activated) is less than or equal to this setpoint, the
LowTemperatureAlarmisactivatedanda“LOWTEMP
ALARM” message is added to the alarm stack. This alarm
deactivateswhen thetemperaturerisesabovethealarm
setpoint value.
1. DisplayMode:All
2. Range:-50CtoMaintainTemperature,Off,-58°Fto
Maintain Temperature, Off
3. Default:5°Cor41°F
4. Restrictions:Messagedoesnotexist ifMaintain
Temperature is set to Off.
7.1.4 High Temp Alarm
ThisvaluesetstheHighTemperatureAlarmsetpoint.
Itmustbegreaterthanthemaintaintemperatureplus
deadband.To disablethisalarmsetthevalueto
“Off”
WhenthemeasuredtemperatureofeitherRTDAorRTDB
(ifactivated)isgreaterthanorequaltothissetpoint,the
HighTemperatureAlarmisactivatedanda“HIGHTEMP
ALARM” message is addedto the alarm stack. The alarm
deactivateswhenthetemperaturefallsbelow thisalarm
setpoint.
1. DisplayMode:All
2. Range:MaintainTemperatureto+500°C,
Off,
MaintainTemperatureto+932°F,Off
3. Default:Off
4. Restrictions:Messagedoesnotexist if
Maintain
Temperature is set to Off.
7.1.5 Low Current Alarm
ThisvaluesetstheLowCurrentAlarmsetpoint.Itmust
be lessthan thehighcurrentalarmsetpoint.Todisable
this
alarmsetthevalueto“Off’.Whentheheatercurrent
is
lessthanorequaltothissetpoint,theLowCurrent
Alarm
is activated and a “LOW CURRENT ALARM”
message is
addedtothealarmstack.Thealarm
deactivateswhen
theHeaterCurrentrisesabove this
alarm setpoint.Note:
This setpoint is based on the
heater at 100% power. If
ProportionalControlor
CurrentLimitingisenabled,all
current measurements
will bescaledto100%power,based
onaconstant
resistiveload,beforebeingcomparedtothe
alarm
setpoint.
1. DisplayMode:All
2. Range:0.1AtoHighCurrentAlarm value,Off
3. Default:Off

Programming CM-2201/CM-2202
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7.1.6 High Current Alarm
Thisvalue setstheHighCurrentAlarmsetpoint.Itmust
begreaterthanthe low currentalarmsetpoint.To
disable thisalarmsetthe value to“Off’.When the
heatercurrent isgreaterthanorequaltothissetpoint,
theHighCurrent
Alarm is activated and a “HIGH
CURRENT ALARM” message
isaddedtothealarm
stack.Thealarmdeactivateswhen
theheatercurrent
fallsbelowthisalarmsetpoint.This
setpoint is based
on the heater at 100% power.
If ProportionalControl or CurrentLimiting isenabled,
all
current measurements will bescaledto 100%
power,based ona constantresistiveload,beforebeing
comparedtothe
alarm setpoint.
1. DisplayMode:All
2. Range:LowCurrentAlarm value to30.0A,Off
3. Default:Off
7.1.7 Ground Fault Alarm
ThisvaluesetstheGroundFaultAlarmsetpoint.Itmust be
lessthanthegroundfaulttripsetpoint.Todisablethis
alarmsetthevalueto"Off'.WhentheGroundFaultCurrent is
greaterthanorequaltothissetpoint,theGroundFault
Alarm
is activated and a "GROUND FAULT ALARM" message
is
addedtothealarmstack.Thealarmdeactivateswhen
the
GroundFaultCurrentfallsbelowthisalarmsetpoint.
1. DisplayMode:All
2. Range:10toGroundFaultTrip,Off
3. Default: 30mA
7.1.8 Ground Fault Trip
ThisvaluesetstheGroundFaultTripsetpoint.Itmustbe
greaterthanthegroundfaultalarmsetpoint.To disable this
tripalarmsetthevalueto“Off’.WhentheGround FaultCurrent
isgreaterthanorequaltothissetpoint,the
heater circuit is
de-energized,theGroundFaultTrip Alarm
isactivated anda
“GROUNDFAULTTRIP” messageis added
to the alarm
stack. This is a latching alarm and trip. When
thecause
ofthealarmhasbeencorrected,thecircuitmay
be
energized by the manual reset function.
1. DisplayMode:All
2. Range:GroundFaultAlarmto500mA,Off
3. Default: 50mA
7.1.9 Low VoltageAlarm
ThisvaluesetstheLowVoltageAlarmsetpoint.Itmust be
lessthanthehighvoltage alarmsetpoint.Todisablethis
alarmsetthevalueto“Off’.WhentheLineVoltageisless
thanorequaltothissetpoint,theLowVoltageAlarmis
activatedanda“LOWVOLTAGEALARM”messageisadded
tothealarmstack.ThealarmdeactivateswhentheLine
Voltagerisesabovethisalarmsetpoint.
Low Voltage Alarm Continued
1. DisplayMode:All
2. Range:85VACtoHighVoltageAlarm,Off
3. Default:Off
7.1.10 High Voltage Alarm
ThisvaluesetstheHigh VoltageAlarmsetpoint.Itmust
be greater than theLowVoltageAlarm setpoint.To
disablethisalarmsetthevalueto“Off’.WhentheHeater
Voltageisgreaterthanorequaltothissetpoint,theHigh
VoltageAlarmisactivatedanda“HIGHVOLTAGEALARM”
Message is added to the alarm stack messages. The
alarm
deactivates when the Heater Voltage drops below
thisalarm
setpoint.
1. DisplayMode:All
2. Range:LowVoltageAlarmto280VAC,Off
3. Default:Off
7.2 Program-HeaterSetup
7.2.1 Heater Setup
Thismessage displaysthename ofthesub-menuwhen
entered.
1. DisplayMode:Advanced
2. Range: N/A
3. Default:N/A
7.2.2 Heater Enable
Thisselectionenables control and monitoringofthe
heater circuit.Setpointsandmeasuredvaluemessages
cannotbe
accessedunlesstheheaterisenabled.Select
“No”ifthe
circuitisnotused.
1. DisplayMode:All
2. Range:Yes, No
3. Default: No

CM-2201/CM-2202 Programming
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7.2.3 HeaterID
This selection allows for user defined Heater
Identification.
Itprovidesaunique,identifiabletagorlabel
foreachheater
circuit.TheHeaterNameallowsupto16
alphanumeric
characterswhichareenteredoneatatime
fromleft toright.Thecursorindicateswhichcharacteris
being
selected.Press the[SELECTUP/DOWN]arrow keys
to change thecharacter.Move tothenext characterby
pressing[NEXT] arrow.Press[ENTER]inthelastcharacter
positiontosave
the Heater ID.
1. DisplayMode:Advanced
2. Range:16Characters (CM-2201)
12Characters (CM-2202)
3. Default: Blank
7.2.4 Heater Type
This selection allows the user to set which type of
heating cable is being used. Self regulating heating cable
should not be used with proportional control, soft-start
mode, or Power limiting; for this reason these options
are unavailable when heater type is set to self
regulating. When heater type is set to fixed resistance all
control options are available. DisplayMode:Advanced
1. DisplayMode:Advanced
2. Range:Self Regulating, Fixed Resistance
3. Default: Fixed Resistance
7.2.5 External Disable
Thisselectionsetstheresponseoftheheatercircuittothe
Override inputs. The Override inputs respond to contact
closure.IftheOverrideissetto“Disable”,theoverrideinputs
are ignored, and control of the heater circuit operates
normallybasedonthemeasuredtemperatureandmaintain
temperature setpoint.If the Override is set to
“Enable”,an
open contact on the override inputs forces
the heater Off.
When thecontact on the overrideinputis
closed,the heater controlresumesinnormalmanner.
1. DisplayMode:Advanced
2. Range:Enable,Disable
3. Default:Disable
7.2.6 Deadband
TheDeadbandisdefinedasthedifferencebetweenthe set
point temperature and the actual maximum temperature
that is ideally allowed in excess of the setpoint
temperature Decreasing the deadband increases the
temperature control
accuracybutalsoincreasestheheater
switchingfrequency.
1. DisplayMode:Advanced
2. Range:1C°to5C°,1F°to10F°
3. Default:2C°or5F°
4. Note:Deadband is disabled forProportional
Control
mode.
7.2.7 Control Type
This selection determines the type of control
method used
by the controller, either On-Off (Deadband)
or Proportional
Control.TheOn-Offcontrolmodeis
availableforallheating
devices. Proportional Control
mode is only available for
series type heating
devices.
1. DisplayMode:Advanced
2. Range: On-Off, Proportional
3. Default: On-Off
4. SelectiondoesnotexistifHeater type is set to
Self regulating.
5. SelectiondoesnotexistifMaintainTemperature
is
set toOff.
7.2.8 Power Limit
Thisselectionsetsthemaximumaveragecurrentlimit
allowedfortheheatercircuit.Itisusefulforreducing
the
poweroutputoffixed resistanceheaters. Theload
will
beturnedonforaperiodoftimeandthenturnedoff
fora
periodoftimetomaintaintheaveragecurrent
drawtothe
value set.
1. DisplayMode:Advanced
2. Range:20% - 100%,Off
3. Default:Off
4. Note:Thevaluerangeisin10%increments.

Programming CM-2201/CM-2202
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7.2.9 Soft Start Mode
ThisfunctionrampstheheateroutputfromOfftonominal
current of the heater over the set soft start cycle
time. It
isusefulforreducinginrushcurrentsofself-
regulating
heaters.Attheendofthesoftstartcycletime,
theloadwill
nolongerbe controlled by the soft start
function.
1. Display: Advanced
2. Range:10 to 999 seconds, Off
3. Default:Off
7.2.10 RTDOperation
This selection determines how the control temperature is
utilizedby the RTD inputs.
−
InOneRTDMode,thetemperatureisbasedonthe
measured temperature from RTD-A.
− InBackupMode,controltemperatureisbasedonRTD-A.
If
foranyreasonRTD-Afails,thenRTD-Btakesover.
− InAverageMode,thecontroltemperatureisbasedonthe
averageofRTD-AandRTD-Bmeasuredtemperatures.
− InLowestMode,controltemperatureisbased on the
lowest
of the two temperature measurements.
−
InHighestMode,controltemperatureisbasedonthe
highest of the two temperature measurements.
− In High Temperature Cut off Mode, control temperature is
basedonRTD-A,butifthetemperaturefromRTD-B
exceeds
thehightemperaturealarm,theheateris
turnedOffanda
high temperature alarm is
activated.TheHighTemperature
cut offmodewill
operateinoneRTDmodeifthehigh
temperature alarm
is turned Off.
FunctionsrequiringtwoRTDstooperate,suchasAverage,
Lowest,HighestandHighTemperatureCut off,willoperate
inOneRTDmodeifoneofthetwoRTDsfail .
1. DisplayMode:Advanced
2. Range:OneRTD,Backup,Average,Lowest,
Highest,
High Temperature Cut off
3. Default: One RTD
Restrictions :Messagedoesnotexist ifMaintain
Temperature is set to Off.
7.2.11 Auto Test Cycle
ThisvaluesetsthefrequencyatwhichtheAutoTestCycleis
activated.AutoTestisafeaturethatexercisesthesystem by
automatically applying power to the heater at
specified timeintervals.Ifanalarmconditionisdetected
duringthis
period,theAutoTestAlarmisactivatedandan
“ALARM
DURINGAUTOTEST”messageisaddedtothe
SystemStatus
messages.Thisisalatchingalarm. Toclearthe
alarm,
locate the alarm message in the Alarm menu
and press
[ENTER]. To disable this feature, set the
value to “Off”. The
AutoTestCycle does notoperateif
heaterisforcedofffor
anyreason,includinggroundfault
trip. AutoTestdecreases
maintenancebyprovidinganearly
warningofproblemsthat
would otherwise go undetected
until the heater was needed.
1. DisplayMode:Advanced
2. Range:1 to720 hours, Off
3. Default:24hours
7.2.11 RTD Failure Mode
Thisselectionsetsthe controllersfail-safemode.The
controllerdetectsifRTD-AhasfailedandwilluseRTD-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.
Forprocesseswherethereisa
potentialhazardfrom
overheating, you may select “Off”,
to de-energize the circuit
untiloneoftheRTD’s becomes
available.
1. DisplayMode:Advanced
2. Range:On,Off
3. Default:Off
Restrictions: MessagedoesnotexistifMaintain
Temperature is set to Off.
7.2.12 Alarm Contact
This selection sets the operating mode of the external
alarm indicator.
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:
1. DisplayMode:Advanced
2. Range:Normally Open, Normally Closed
3. Default:Normally Open

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7.3 Program–SystemSetup
7.3.1 System Setup
This message displaysthe name ofthe 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 forprogrammingchanges.Thedisplaywill
show“disable” ifprogramaccessiscurrentlyenabled
andshow“enable”if programaccessiscurrently
disabled.
1. DisplayMode:All
2. Range:EnableorDisable
3. Default: Enable
7.3.3 Change Password
This selection allows the user to change the default
password. The user is prompt to re-enter the old
password, press [ENTER]. If correct, the user is prompt to
enter the new password, press [ENTER]. The user is then
prompt to re-enter the new password. If the user does
not enter the new password and press [ENTER] then the
password does not change.
1. DisplayMode:All
2. Range:Yes, No
3. Default: No
7.3.4 Units
Thisselectiondeterminestheunitofmeasurefor
temperature values. All temperatures are displayed in
the selectedunitsofeitherCelsiusdegrees(C°)or
Fahrenheit degrees (F°).
1. DisplayMode:Advance
2. Range:Celsius,Fahrenheit
3. Default: Celsius
7.3.5 Operational Costs
ThisvaluesetsthecostperkWhofelectricalpower.This is
usedtocalculateenergycostsforoperatingthiscontrol
circuit.
1. DisplayMode:Advance
2. Range: $0.01to 1.00
3. Default:$0.05
7.3.6 Display Mode
Thisselectiondetermineswhatmessagesaredisplayedby
the controller for operations personnel. If set to
“advanced user”. allmessages aredisplayed.Ifset to
“normaluser”, only the basic messages are displayed.
Each message listed throughoutthismanualshowsthe
DisplayModerequired
toseethemessage.“Advancedonly”indicatesthatthe
displaymodemustbesetto “advanceduser”toviewthe
message.
1. DisplayMode:All
2. Range:Normal,Advance
3. Default: Advance
7.3.7 Default Display
Thisfunctionspecifiestheinformationthatwillbe
displayedwhennokeyhasbeenpressedfortheDisplay
Timeout interval as described below.
1. Range:SystemStatus,HeaterStatus,HeaterTemp
2. Default:systemstatus
3. Restrictions: Temperature messages are
not displayedifMaintainTemperatureisset
toOff.
VALUE INFORMATION
DISPLAYED
System status Alarm status of
all the heaters
Heaterstatus Alarmstatusof
the heater
Heater temp Temperature of
the heater

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7.3.8 Display Timeout
Thisfunctionsetsthelengthoftimefromthelastkey
press, to automatically return to the Default Display
information. Selecting“Off’disablesthisfunction.
1. DisplayMode:Advance
2. Range:5 to 600 seconds, Off
3. Default:120seconds
7.3.9 Modbus Address
This selection sets a unique addresstoensure only one
CM- 2201attemptscommunicationswiththemasterunit
atany time.SeeSection8.0forcompleteinformationon
Modbus communications.
1. DisplayMode:Advance
2. Range:1to255toaccommodatemultiple
deviceson same network.
3. Default: 1
7.3.10 Baud Rate
SetsthecommunicationbaudratefortheRS485serial
port. Allcontrollersconnectedtothesamedatahighway
must operateonthesamebaudrate.
1.DisplayMode:Advance
2.Range:2400,4800,9600,19200
3.Default:9600
7.3.11 Reset Module
This selection resets controller memory parameters to
factory default values. If the controller’s 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-SystemTest
7.4.1 System Test
This message displaysthe name ofthe 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
purposesallowingthealarmoutputtobeforcedOneither
forashortperiodoftimeorcontinuously.Attheendofthe
specified time duration, the testing option is
automatically disabled.Thealarmtestfunctionwillnot
operateifthe alarm configuration is setto disable andthe
message “ALARMDISABLED”willappear.
1. DisplayMode:Advanced
2. Range:1-24hours,Disabled,Continuously
3. Default: disabled
7.4.3 Heater Test
This function overrides heater control for
maintenance purposes.Fornormaloperation,setto
“disable”.Ifa period oftimeisselected,theheateris
forcedOnorOffforthe selectedinterval.If“continuous”is
selectedtheheateris forcedOnuntil“disable”isselected.
1. Display Mode:Advanced
2. Range:1-24hours,Disabled,OnContinuously
3. Default: disabled
7.4.4 Ground Fault Test
Thisfunctionwilltestthegroundfaulttripfunctionof
the controllerto ensure proper operation. When
selected, the controller will generate an artificial
ground fault current; if theground faultcurrent is
sensedasbeing greater than 30
mA,thetestpasses.
TheGFtestfunctionwillverifyactual groundfault
currentandheatertrip. Statusofthetestwill be
displayed as pass or fail. If this test has been
invoked bythe“Now”optionanditpasses,theuseris
promptedto
resetthegroundfaulttrip,atwhichtime
theloadiscapableofbeingre-energizedasrequired. If
thistesthasbeen invokedbythe“Autotest”option
anditpasses,theloadis allowedtobereenergizedas
required. Ifthistesthasbeen invokedbytheAutotest
cycleanditfails,an Autotestalarm isgeneratedbut
theloadisallowedtobere-energizedas required.
1. DisplayMode:Advanced
2. Range: Autotest cycle, Now, Disabled
3. Default: Disabled

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8.0 Communications
TheNelson HeatTraceCM-2201supportsa subsetof the Modbus
®
RTUprotocolformatthatprovidesmonitoring,
programming,andcontrolfunctions usingRead (03)and Write(05-06)registercommands.
General Information
Serial Port: Selecttheserialport that correspondstoyourRS-485 adapter.
USB to Serial adapter maybeusedfordeviceswithout serial connections.
BaudRate: UserDefinedat2400, 4800,9600or19200
Data Bits: 8
StopBits: 1
Parity: None
Device Address: UserDefinedbetween1and255
Modbus Registers
ForallModbusregister addresses, seeAppendixE .
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 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
Note: The DPC can read up to 45 addresses per command

Troubleshooting CM-2201/CM-2202
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9.1 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
u
nderstanding of its operation.
Todetermineifafaultisassociatedwiththe heattracing,
wiringorthecontroller,itwillbenecessary totroubleshoot
thewiringandtracercircuit.Ifthe
Fault remains, remove power from the controller and exchange
it with another controller. This may require some
reprogrammingofthenewCM2201/CM-2202.Refertothe
following sections for the appropriate topic.
9.2 Ground Fault
Groundfaultwarning/alarmscanbecaused byincorrect
installation as well as current leakage resulting from wet
system components or damaged cables.
TheCM2201/CM2202Controllerdetectsgroundfaultsby
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 isaflowofcurrent from
one of the trace supply wires to ground,a ground
fault condition occurs.
Ifagroundfaultalarmispresentonstart-upofanew
installationitislikely duetoawiringerroror damaged
cable.
To verify this condition:
a) Checkthattheheatingcircuitneutralsreturnto
the controller and are not connected directly to
the
distributionpanel.Thiscanbeacommon
problemifthe
installationisaretrofitsituation.
b) Onparalleledcircuits,becertainthatALLneutrals
return.Thelateadditionofacircuitmaynotbeobvious.
Note: The controller monitors the integrity of the ground
fault(GF)detection.If a fault is detected,the controller
will generateaGFIwarning/alarmdependofthesettings.
9.3 RTDs
RTD failuresafterinstallationcangenerallybeattributed to
incorrect wiring or improper installation of the sensor.
Troubleshootingofthesefailuresisaverysimpleprocedure
if
the proper steps are undertaken in the correct order.
SomespecificRTD problemsandthecorrectmethodsfor
troubleshooting are outlined as follows.
1. RTD Failure Alarm(s)
IftheCM2201/CM-2202controllerindicatesafailureofan RTD:
a) EnsurethattheRTDisa3-wire100(PlatinumType).
TURN THE POWER TO THE CONTROLLER OFF BEFORE
PROCEEDING!
b) DisconnecttheRTD wiringfromtheinputterminals.
c) MeasuretheRTD’sresistancebetweenthesource(RED) and
sense(RED)leadsat the controller(itshouldnot exceed40
Ω). Excessiveleadresistance willcausea RTD FAILURE
ALARMandmustbecorrected.Lookforloose
terminals,
excessive lead length, or insufficient wire
gaugeandcorrect
asnecessary.
d) MeasurestheRTD’sresistancebetweenthesource(RED) or
sense(RED)leadandthecommon(WHT)leadofthe RTDat
the controller(shouldbe between60and330 Ωdepending
on the temperature and the lead resistance. Verify
thattheRTDiswiredcorrectly—theheattracing
controllers
will always be terminated in the order: source
(RED),
common(WHT),sense(RED).
Whenwiringtothe CM2201/CM2202,theterminalsaremarkedas
follows:
Terminal No.
Description
GNDBus Shield
RA
RTD A Source (RED)
WA
RTD A Common(WHT)
RA
RTD A Sense(RED)
GNDBus
Shield
RB
RTD B Source (RED)
WB
RTD B Common(WHT)
RB
RTDB Sense(RED)
The RTD manufacturer will typically color code the leads with
thesourceandsensebeingthe samecolor,and the
common a
different color. Ensure that the RTD extension
wireshieldis
terminatedatoneendonly,normallyusingthe
terminal block
provided at the terminal board.

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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 asthe White-White-
Redcolorscheme)andtheWhiteandBlack connections maybe
used interchangeably.
2. Temperature Verification
Ifyouconsiderthattheindicatedordisplayedtemperature is
notcorrect,the controller and theRTD can be quickly
checkedforcorrectoperation.ToverifytheRTD:
TURNTHEPOWERTOTHECONTROLLEROFFBEFORE
PROCEEDING!
a) DisconnecttheRTD wiringfromtheinputterminals.
b) To calculate the temperature indicated by the RTD,
measure the resistance from source (red wire) or
sense
(red wire) to common(whitewire) and subtract
the resistancemeasuredbetweensourceandsense.This
will give a compensatedresistancevaluethat canbe
cross-
referenced to one of the RTD tables found in
Appendix
EorAppendixF. Comparethemeasuredresistanceand
cross-referenced temperature value obtained from the
RTD table to the indicated or displayed value. These
shouldagreetowithintheaccuracystandardsofthe
CM2201/CM2202and the RTD.
Note: Ensure you refer to the correct RTD table for the type of
RTDyouareusing
ToverifytheController:
TURNTHEPOWERTOTHECONTROLLEROFFBEFORE
PROCEEDING!
a) DisconnecttheRTD wiringfromtheinputterminals.
b) Connect a100Ωresistor across the source or
sense
terminal and common. Insert a jumper
betweenthe
sourceandsenseterminals.
c) Apply power to the controller. The indicated or
displayed
temperatureshouldbeabout32°F(0°C)
dependingon
theactualresistanceofthetestresistorif
RTDTYPEis
setto100ΩPlatinum.Anyresistormay
havea+/-10%
tolerance.
3. Unstable Temperature
Anerraticindicationoftemperaturecanbecausedby several
factors external to the controller. The controller’s
accuracyand
resolutionwillresultinanindicated
temperaturechangeofa
coupleofdegreesifthemeasured
resistance temperature
falls between two discrete values
(thisissometimes
referredtoasquantizationerror).
Iftheinstabilityisexcessive,check:
a) Wire used for extension of the RTD should be three-
wire,
twistedandshieldedwiththeshieldgroundedatthe
controlleronly.Eachofthethreeleadwiresmustbeof the
samegauge.
b) Theidealinstallationhasaseparateconduit forthe RTD
leads(iftheyhavebeenextended). Itisnotusually
a
problem torun lowsignal levelsin the sameconduit
as
thepowerleads even inhigh power applications,as
long
astheRTDwireis atwisted,shieldedtypewithan
insulationratingequaltoorgreaterthanthehighest
voltage in the conduit. Follow the proper Electrical Code
requirements for your particular installation.
c) Check thespecificationsfortheparticularcable
beingusedtoensurethatitdoesnothaveexcessive
Capacitance when used in long lengths. This can
cause a
temperature offset between what the controller
reads and
whattheRTDactuallymeasures.Thisagainis
normally
notaproblemsincethecontrollercompensates
forall
buttheworstcasesofthis.
d) CheckonebyoneiftheallRTDleadsareconnectedto
theconnector.
e) Lastly, it is possible for the RTD itself to fail
on an
intermittentbasis,butthisfailuremode
shouldbe
consideredunusual.Thiskindoffailureis
probablythe
mostdifficulttofindbutfortunatelyitis
alsotheleast
likelyasafailuremechanism.

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9.4 Common Warnings/Alarms - What to Look for
The CM-2201/CM-2202 has a wide range of warning
and
alarming featuresthatmaybeselectivelyenabledor
disabled to allow the monitoring and indication of
trouble
conditions. Describedbelowarethedifferent
warmingand
alarm conditionsavailableontheCM-
2201/CM-2202,their
meanings,and possible causes.The
warningsettings must
be below alarm settings.Ifan
alarmwill be activatedthe
twoSSRlowpowerwillbe
activated.
9.4.1 Continuity Failure
The “Continuity Failure” alarm indicates that the current being
drawn by the load is less than about 0.5 Amps and hence the
load is assumed to be disconnected
9.4.2 HighCurrentWarning/Alarm
ThisWarning/alarms currentlevelsthataregreaterthanthe
HIGHCURRENTWARNING/ALARMsettingfortheapplication.
Cause of Warning/Alarm:
• Warning/Alarm setting too close to normal
operating
current
• Highin-rushcurrentfrom“coldstart”ofselfregulating
cable
• Damagedorpartiallyshortedheatingcable
• “ Asbuilt” cablelength isgreater thandesign value
9.4.3 LowCurrentWarning/Alarm
This alarmscurrentlevelswhichare lessthantheLOW
CURRENT WARNING/ALARM setting.
Cause of Warnings/Alarm:
• Warning/Alarm setting too close to normal
operating current
• Low source voltage
• Damagedorinoperativeheatingcable
• Openconnection—wiringproblem
• SSRorcontactorfailedopen
9.4.4 Overcurrent Trip
Ifthecontrollerisunabletostartthecableduetohigh current or
after attempting to soft start it, the controller will
tripitsoutput
switchoff.
CauseofAlarm:
• Excessivein-rushcurrent
• IncorrectCM-2201/CM2202settings
• Incorrect wiring
• Damagedcable
9.4.5 Power Limiting (Current Limiting)
This alarm indicates that the solid-state relay is limiting the
averageamountofpowerthat isappliedtothetracecircuit
asdefinedbytheMAXIMUMPOWERsetting.
CauseofAlarm:
• Powerappliedtotracecircuitisbeinglimitedto
the
MAXIMUMPOWERsetting
9.4.6 HighGFIWarning
Thiswarninggroundfaultcurrentlevelswhicharegreater
thantheHIGHGFIWARNING setting.
CauseofWarning:
• Warningsettingtooclosetonormalleakagecurrent
• Damagedcableinsulationand/ormoisturepresent
• Moisture in junction box
• Poor splice or termination
• Moistureprovidesconductivegroundpathwhichallows
ground fault current
9.4.7 GFIAlarm
Thisvaluesetstheupperlimitofallowablegroundfault
leakage.Exceedingthislimitwillresultintheoutputswitch
beinglatchedoffandthealarmactivatedtoindicatea
ground fault condition.
CauseofAlarm:
• Tripsettingtoocloseto normalleakagecurrent
• Damagedcableinsulationand/ormoisturepresent
• Moisture in junction box
• Poor splice or termination
Moistureprovidesconductivegroundpath
whichallows
ground fault current
9.4.8 Switch Failure
Thisalarmindicatesthatthecontrollersensescurrentflow
whentheoutputswitchshould beoff.
Cause ofAlarm
• Some other device energized heat trace
• Outputswitchhasfailed“closed”

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9.4.9 High RTD A/ RTD BTemperatureReading
This warning/alarm appear 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
• Steamingout lines
• Incorrect tracer wiring
9.4.10 Low RTD A/RTD BTemperatureReading
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,ormissing insulation
• Heating cable not sized properly for the application
9.4.11 RTD A/RTD BFailure
This alarm indicates a sensor is not operating properly. The
temperature sensor may fail due to an “open” or “shorted”
condition.
CauseofAlarm:
• Incorrectordamagedfieldwiring-openleadsorexcess
resistance(eitherintermittentorcontinuous)maybedue to
brokenordamagedwiresorlooseterminals.
• Damaged or inoperative temperature sensors
9.4.12 EEPROM Data Failure
Thisalarmindicatesthatthecontrollerhasdetecteda
failureinitsnon-volatilememory(thisiswhereallofthe
controller’s configuration and calibration settings are
stored).Thisindicatesaninternalproblemandthe
CM2201/CM2202 should be replaced and returned to
the
factory for repair.
CauseofAlarm:
• TheCM-2201/CM2202cannotbypassthefailedareaofits
memoryandhasloadedfactorydefaultsintothisfailed
area
.
9.4.13 HighVoltageWarning/Alarm
Thiswarning/alarmsvoltagelevelsthataregreaterthanthe
HIGH VOLTAGE WARNING/ALARM setting.
Cause of Warning/Alarm:
• Warning/Alarmsettingtooclosetonormaloperatingvoltage
• Incorrect wiring
• Power surge
9.4.14 Low Voltage Warning/Alarm
Thiswarning/alarmsvoltagelevelsarelessthantheLOW
VOLTAGE WARNING/ALARM setting.
Cause of Warning/Alarm:
• Warning/Alarm setting too close to normal operating
voltage
• Damagedpowercable
• Incorrect VOLTAGE TURNS RATIO
• “Brown-out” conditions
• Lossofpowertothecircuit

Maintenance CM-2201/CM-2202
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10.0 Maintenance
TheCM-2201/CM-2202shouldberegularlymaintainedasfollows:
a) Checkfitofdoorgasketandadjustasrequired.Clean
door gasket.
b) Verifythatmoistureisnotenteringenclosure;repairas
required.
c) Checkterminalstoensureconnectionsaresecure.
d) Checkwiringforanysignsofoverheating.
e) Cleanfrontpanelwithmildsoapondampcloth.
Warning: Donotuseanyclothfromsyntheticmaterialor
similar. Thecleaningprocessmaycausethefrontlabelto charge
electrostatically and touching the front panel may generate
s parks.