Omron E5AR - MANUAL 2 User Manual page 303

Section 10 Troubleshooting
● Overshoot or undershoot occurs
Abnormal measured value.
A regular slow thermal response temperature
sensor is connected to a fast thermal response
control system.
The proportional band is too narrow; the P value is
too small.
The integral time is too short; the I value is too
small.
The derivative time is too short; the D value is too
small.
ON/OFF control is being performed.
The control period is too long in a fast thermal
response control system.
Overlap band is mistakenly set as a dead band in
heating/cooling control.
● Hunting occurs
Check connections and settings as explained above in "Overshoot or undershoot occurs".
The heat capacity of the heater is too large for the
heat capacity of the object of control.
Periodic disturbances occur that cause the heat
capacity of the object of control to change.
AT is running.
10-6
Possible cause
Possible cause
Solution
See section 10.3.
Change to a sheath-type temperature sensor.
• Increase the P value within the limit that the
response speed does not become too slow.
• Run AT.
• Increase the I value within the limit that the
response speed does not become too slow.
• Run AT.
• Increase the D value within the limit that stability
during rectification does not deteriorate.
• Run AT.
Use P control or PID control.
Shorten the control period.
Set to overlap band.
Solution
Use a heater with a heat capacity suitable for the
object of control.
Establish an environment will minimal
disturbances.
Hunting will stop when AT ends.