User guide

Watlow EZ-ZONE
®
PM PID Controller • 109 • Appendix
Indication Description Possible Causes Corrective Action
[LP;o1]
Loop Open Error
Open Loop Detect is active and
the process value did not devi-
ate by a user-selected value in
a user specified period.
•SettingofOpenLoopDetect
Time incorrect
•SettingofOpenLoopDetect
Deviation incorrect
•Thermalloopisopen
•OpenLoopDetectfunctionnot
required but activated
•SetcorrectOpenLoopDetect
Time for application
•SetcorrectOpenLoopDevia-
tion value for application
•Determinecauseofopenther-
mal loop: misplaced sensors,
load failure, loss of power to
load, etc.
•DeactivateOpenLoopDetect
feature
[LP;r1]
Loop Reversed Error
Open Loop Detect is active and
the process value is headed
in the wrong direction when
the output is activated based
on deviation value and user-
selected value.
•SettingofOpenLoopDetect
Time incorrect
•SettingofOpenLoopDetect
Deviation incorrect
•Outputprogrammedforincor-
rect function
•Thermocouplesensorwiredin
reverse polarity
•SetcorrectOpenLoopDetect
Time for application
•SetcorrectOpenLoopDevia-
tion value for application
•Setoutputfunctioncorrectly
•Wirethermocouplecorrectly,
(red wire is negative)
[`rP1] Ramping 1
Controller is ramping to new set
point
•Rampingfeatureisactivated •Disablerampingfeatureifnot
required
[tUN1] Autotuning 1
Controller is autotuning the con-
trol loop
•Userstartedtheautotune
function
•Digitalinputissettostart
autotune
•Waituntilautotunecompletes
or disable autotune feature
•Setdigitalinputtofunction
other than autotune, if desired
No heat/cool action Output does not activate load •Outputfunctionisincorrectly
set
•Controlmodeisincorrectlyset
•Outputisincorrectlywired
•Load,powerorfuseisopen
•Controlsetpointisincorrect
•Incorrectcontrollermodelfor
application
•Setoutputfunctioncorrectly
•Setcontrolmodeappropriately
(Open vs Closed Loop)
•Correctoutputwiring
•Correctfaultinsystem
•Setcontrolsetpointinappro-
priate control mode and check
source of set point: remote, idle,
profile, closed loop, open loop
•Obtaincorrectcontrollermodel
for application
No Display No display indication or LED il-
lumination
•Powertocontrollerisoff
•Fuseopen
•Breakertripped
•Safetyinterlockswitchopen
•Separatesystemlimitcontrol
activated
•Wiringerror
•Incorrectvoltagetocontroller
•Turnonpower
•Replacefuse
•Resetbreaker
•Closeinterlockswitch
•Resetlimit
•Correctwiringissue
•Applycorrectvoltage,check
part number
No Serial Communication Cannot establish serial commu-
nications with the controller
•Addressparameterincorrect
•Incorrectprotocolselected
•Baudrateincorrect
•Parityincorrect
•Wiringerror
•EIA-485converterissue
•IncorrectcomputerorPLC
communications port
•Incorrectsoftwaresetup
•Terminationresistormaybe
required
•Setuniqueaddressesonnet-
work
•Matchprotocolbetweendevices
•Matchbaudratebetweende-
vices
•Matchparitybetweendevices
•Correctwiringissue
•Checksettingsorreplacecon-
verter
•Setcorrectcommunicationport
•Correctsoftwaresetuptomatch
controller
•Place120Ωresistoracross
EIA-485 on last controller
Troubleshooting Alarms, Errors and Control Issues (cont.)