Omron E5AZ, Руководство пользователя

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51
Using HB and HS Alarms
Section 3-10
• If there is little difference between the current in normal and abnormal
states, detection may become unstable. To stabilize detection, set a cur-
rent value difference of at least 1.0 A for heaters of less than 10.0 A, and
at least 2.5 A for heaters of 10.0 A or more. If the heater current is too
low, loop the load line several times through a CT, as shown in the dia-
gram below. Looping it through once will double the detection current.
3-10-2 Installing Current Transformers (CT)
• This function can be used with E5 @ Z models that have the HB alarm and
HS alarm.
For the E5CZ, connect the CT in advance to terminals 14 and 15 (CT1).
For the E5AZ/EZ, connect the CT in advance to terminals 14 and 15
(CT1). Then pass the heater power line through the CT's hole.
For specifications, models and dimensions of current transformers that
can be used with this Controller, see
Appendix A Current Transformer
(CT) page 153.
Single-phase Heaters For single-phase heaters, install the CT in the position shown in the following
diagram.
3-10-3 Calculating Detection Current Values
• Calculate the set value using the following equation:
• To set the current for heater burnout when two or more heaters are con-
nected through the CT, use the value from when the heater with the
smallest current burns out. If all of the heaters have the same current, use
the value from when any one of them burns out.
• Make sure that the following conditions are satisfied:
Heater with a current of less than 10.0 A:
(Current value at normal operation)
−
(Current value at heater burnout)
≥
1 A
When the difference is less than 1 A, detection is unstable.
Heater with a current of 10.0 A or more:
(Current value at normal operation)
−
(Current value at heater burnout)
≥
2.5 A
When the difference is less than 2.5 A, detection is unstable.
CT
Load line
CT
Load
Load (such as a heater)
AC line
Product
To CT input
Heater Burnout Detection 1 set value = Normal current value + Burnout current value
2
HS Alarm 1 set value = Leakage current value (output OFF) + HS current value
2