58
Heater Burnout Detection
Section 5-9
5-9
Heater Burnout Detection
Overview
The heater burnout detection function is used to compare a preset heater
resistance value with the estimated resistance during operation to detect a
“burnout” and output an alarm if the resistance during operation rises above
the criteria.
The present resistance is estimated based on the present output value and
the current detected by the built-in CT.
Note
The accuracy of heater burnout detection will be lower for heaters for which
the resistance significantly changes depending on the temperature. If the rate
of change in the heater resistance exceeds the criteria for detecting a heater
burnout, a false heater burnout will be detected. The criteria for detecting a
heater burnout is set in the Heater Burnout Threshold parameter (HBR).
Relationship between Parameters and Resistance
The following diagram shows the relationship between the heater burnout
detection parameters and the resistance.
Basic Parameters
Before the heater burnout detection function can be used, the following two
parameters must be set.
• Heater Burnout Alarm Operation [P14] (in initial setting level)
Current
Heater
CT
CT
Burnout
Current is reduced.
Normal resistance
is stored.
Resistance increase
of 1.5
×
is detected.
Heater
Resistance
Heater burnout determination area
Output value
Normal resistance
Resistance after burnout
Heater Characteristic
Resistance
Heater Burnout
Threshold
Heater Burnout
Detection Lower Limit
Summary of Contents for G3PW
Page 1: ...Cat No Z280 E1 01 User s Manual G3PW Power Controllers...
Page 2: ...G3PW Power Controllers User s Manual Produced November 2008...
Page 3: ...iv...
Page 15: ...xvi...
Page 49: ...34 Wiring for Specific Applications Section 3 4...
Page 61: ...46 Setting Parameters in the Initial Setting Level Section 4 6...
Page 77: ...62 Heater Burnout Detection Section 5 9...
Page 113: ...98 Parameter Settings in the Adjustment Level Appendix B...
Page 117: ...102 Index...
Page 119: ......