Calculating The Detection Current Value - Omron E5ZN Operation Manual

Using Heater Burnout Alarm (HBA)
3-9-3

Calculating the Detection Current Value

Application Examples
Control output
Heater
1 kW
CT
Control output
Heater
1 kW ´ 3
CT
36
Note To detect heater burnout for a 3-phase heater, use the K2CU-F@@A-@GS (with gate
input terminal). For details, see the data sheet.
• Calculate the set value by the following equation:
Set value =
• To set the value of the heater burnout when two or more heaters are con-
nected through the CT, use the current value of the smallest heater con-
nected. If all the heaters have the same current value, use the current
value when one of the heaters burns out.
• Make sure that the following conditions are satisfied:
Heater of current 10.0 A or less:
Normal current -Current at heater burnout ³ 1 A
(When the resultant current is less than 1 A, detection is unstable.)
Heater of current 10.0 A or more:
Normal current -
Current at heater burnout ³ 2.5 A
(When the resultant current is less than 2.5 A, detection is unstable.)
• The setting range is 0.1 to 49.9 A. Heater burnout is not detected if the set
value is 0.0 or 50.0. If the set value is 0.0, the heater burnout alarm is
turned OFF, and if the set value is 50.0, the heater burnout alarm is turned
ON.
• Set the total current value at normal heater operation to 50 A or less.
Example 1
Current during normal operation =
Current at heater burnout = 0 A
Set value =
200 VAC
(Normal current - Current at heater burnout) = 5 - 0 = 5 A ( ³ 1 A)
Example 2
Current during normal operation =
Current at burnout of one heater =
Set value =
200 VAC
(Normal current - Current at heater burnout) = 15 - 10 = 5 A ( ³ 2.5 A)
(Normal current + Current at heater burnout)
2
Using a 200-VAC, 1-kW Heater for OUT1
1000
200
5 + 0
= 2.5 A
2
Using Three 200-VAC, 1-kW Heaters for OUT2
1000
200
1000
200
15 + 10
= 12.5 A
2
= 5 A (< 10 A)
´ 3 = 15 A ( ³ 10 A)
´ 2 = 10 A
Section 3-9