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Determining the Error from the Current Situation for Temperature Control Errors
Section 8-6
Overshooting or Undershooting
Hunting
The troubleshooting items for connection and setting problems are the same as for overshooting and under-
shooting, above.
Possible cause
Countermeasure
Connection Measured temperature is wrong.
• Perform the action outlined in 7.5.
A general-purpose thermometer with slow thermal
response has been connected to a control system with fast
thermal response.
• Change to a sheathed thermometer.
Setting
The proportional band value is too low.
• Increase the proportional band within a range with an
acceptable response delay.
• Execute AT (or ST with
) to make the PID adjustments.
The integral time is too short.
• Increase the integral time within a range with an acceptable
response delay.
• Execute AT (or ST with
) to make the PID adjustments.
The derivative time is too short.
• Increase the derivative time within a range that does not
adversely affect the stability of stabilization time.
• Execute AT (or ST with
) to make the PID adjustments.
ON/OFF control is operating.
• Execute P control or PID control.
The control cycle is too long for the control system with its
fast thermal response.
• Shorten the control cycle.
The overlap band in the heating and cooling control is set to
a dead band by mistake.
• Set to an overlap band.
V1.2
V1.2
V1.2
Possible cause
Countermeasure
Procedure The heater's heating capacity is too large for the heating
capacity of the control target.
• Use a heater with a heating capacity suitable for the control
target.
There is periodic disturbance, which changes the heating
capacity of the control target.
• Change to an environment with as little periodic distur-
bance.
Executing autotuning (AT).
• Hunting will not occur once autotuning has been completed.
Summary of Contents for EJ1 EtherCAT
Page 2: ...EJ1 Modular Temperature Controllers User s Manual Revised July 2008 ...
Page 3: ...iv ...
Page 19: ...xx ...
Page 213: ...188 Detailed Description of Services Section 6 4 ...
Page 227: ...202 Detailed Description of Services Section 7 5 ...
Page 303: ...278 Index ...
Page 305: ......