Using Heater Burnout Alarm (Hba); Hba Detection; Operating Conditions - Omron E5ZN Operation Manual

Using Heater Burnout Alarm (HBA)

3-9

Using Heater Burnout Alarm (HBA)

3-9-1

HBA Detection

3-9-2

Operating Conditions

To CT terminal
Heater burnout detection works as follows:
1,2,3... 1. Pass the heater lead through the current transformer (CT) hole. For spec-
ifications, models, and external dimensions of current transformers that
can be used on this Controller, refer to Current Transformer (CT) in Appen-
dix A.
2. When current flows through the lead, the current transformer generates AC
current proportional to the current value. The E5ZN measures this AC cur-
rent to calculate the current flowing to the heater.
3. If the heater is burned out, the current measured at the current transformer
will decrease. If this value becomes larger than the value set as the heater
burnout set value, the output is turned ON to indicate a heater burnout
alarm.
• Set the heater burnout detection value in the "heater burnout detection"
parameter. To monitor the current value of the current transformer, use
the "heater current monitor" parameter.
• When you are not using the HBA function, set the "heater burnout"
parameter to "0: OFF."
• Make separate heater burnout settings for ch1 and ch2.
• Be sure to connect the CT to the E5ZN, and pass the heater lead through
the CT hole.
• Turn ON the heater at the same time as or before turning the E5ZN. If the
heater is turned ON after turning the E5ZN, the heater burnout alarm will
activate.
• Control is continued even if the heater burnout alarm is turned ON. (That
is, the E5ZN attempts to control heaters for which the heater burnout
alarm has not occurred.)
• Heater burnout detection is performed when the control output is continu-
ously ON for 190 ms or more.
• The rated current value may sometimes differ slightly from the actual cur-
rent flowing to the heater. Check the current value in an actual operating
state in the "heater current monitor" parameter.
• If there is little difference between the current in a normal state and the
current in the burnout state, detection may be unstable. On a heater with
a current 10.0 A or less, maintain a difference of 1.0 A or more. On a
heater with a current 10.0 A or more, maintain a difference of 2.5 A or
more.
• The HBA function cannot be used when the heater is controlled by a
phase control system or cycle control system. Also, 3-phase heaters can-
not be used.
CT
Heater lead
Section 3-9
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