Omron G3PW, User Manual

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Heater Burnout Detection Section 5-9
Parameters for Heater Burnout Judgment Conditions
The following parameters are used to set the conditions for detecting a heater
burnout. Use them according to the load environment.
• Heater Burnout Threshold (HBR): Adjustment level
• Heater Burnout Detection Lower Limit (HBL): Adjustment level
• Number of Alarms for Heater Burnout Detection [P09]: Initial setting level
Rate of Change in
Resistance for Heater
Burnout Detection The threshold for determining a heater burnout when the resistance increases
must be set as a percentage of the present resistance using the Heater Burn-
out Threshold parameter [HBR]. The following formula is used to determine
heater burnouts.
An approximate value for the Heater Burnout Threshold can be calculated
with the following formula.
Heater Burnout Threshold = 90
÷
Number of heater elements
For example, if you want to detect the burnout of one element for a heater with
three elements, set the Heater Burnout Threshold to 30.
Note (1) If the default value of 100 is used, burnout of all heater elements will be
detected.
(2) If the Heater Burnout Threshold is too small, the alarm output may be un-
stable.
Heater Burnout Detection
Lower Limit The Heater Burnout Detection Lower Limit parameter is used to limit the
range of output values for heater burnout detection. The default setting is 0.0.
If alarms are frequently occurring for small outputs in normal operation, then
limit the range of output values to be detected.
Number of Alarms for
Heater Burnout Detection The Number of Alarms for Heater Burnout Detection parameter is used to set
the number of cycles for which heater burnout is to continue until an alarm will
be output. The default setting is 150.
Note If a number of 10 or lower is set for the Number of Alarms for Heater
Burnout Detection parameter, the alarm may operate incorrectly
with a sudden change in the MV.
Display Name Range
HPR Heater Characteristic Resistance for Phase Control 0.0 to 99.9
HCR Heater Characteristic Resistance for Optimum Cycle
Control 0.0 to 99.9
100
−
Heater Burnout Threshold
100
Present resistance
≥
Characteristic resistance of heater
×
Display Name Range
HBR Heater Burnout Threshold 1 to 100
Display Name Range
HBL Heater Burnout Detection Lower Limit 0.0 to 100
Display Name Range
[P09] Number of Alarms for Heater Burnout Detection 0 to 999