Omron E5ZN Operation Manual page 189

Temperature Control Errors
Operation Controlled object is radiating heat.
Controlled object is influenced by large over-
shooting.
Overshooting or Undershooting
Connections PV of the E5ZN is abnormal.
General-purpose temperature sensor with slow
thermal response characteristics is being used to
sense a controlled object with quick thermal
response characteristics.
Settings E5ZN has a narrow proportional band and small P
constant.
E5ZN has a short integral time or small I constant. • Increase the I constant keeping within the
E5ZN has a short derivative time or small D con-
stant.
E5ZN is executing ON and OFF control.
Control period is too long when the E5ZN controls
the temperature of an object with quick thermal
response characteristics.
Dead band instead of an overlap band is set with
the E5ZN in heating and cooling control opera-
tion.
Hunting
Operation Heat capacity of a heater controlling the tempera-
ture of an object is too large for the object.
Heat capacity of a controlled object changes due
to periodical external disturbances.
E5ZN is executing autotuning.
Probable cause
Probable cause
For troubleshooting problems with connections and settings, refer to the same
probable causes and remedies as provided for overshooting and undershoot-
ing.
Probable cause
Remedy
Execute heating and cooling control.
Refer to the following table regarding overshoot-
ing and undershooting for appropriate trouble-
shooting.
Remedy
Refer to 8-3 Temperature Sensing Errors for
appropriate troubleshooting.
Change to a sheath-type temperature sensor.
• Increase the P constant keeping within the
range where the response delay caused by the
P constant can be allowed.
• Execute autotuning.
range where the response delay caused by the
I constant can be allowed.
• Execute autotuning.
• Increase the D constant keeping within the
range where the D constant will not have an
undesirable influence on temperature stability.
• Execute autotuning.
Execute P or PID control.
Shorten the control period.
Set the overlap band of the E5ZN.
Remedy
Use a heater with a heat capacity suited to the
object.
Take appropriate measures to prevent the period-
ical external disturbances.
Hunting will not occur if autotuning is completed.
Section 8-4
175