Heater Short Alarm (Hs Alarm) - Omron EJ1 User Manual

Detecting Current Errors
Normal Operation
10 A
200 V
To CT input
200 V
17.3 A
200 V
10 A
To CT input
Heater Burnout Occurred
5 A
200 V
To CT input
200 V
Burnout
200 V
5 A
To CT input
Current when there is a burnout = 10 A ×
4-5-3

Heater Short Alarm (HS Alarm)

c. V Connection
Example: Using Two 200-VAC, 2-kW Heaters
CT
CT
CT
200 V
Load: Heater
(example)
CT
1
-- -
2
= 5 A
The heater burnout current when there is a burnout at the common is as fol-
lows:
Heater burnout detection current =
The heater burnout current when there is a burnout at the load is as follows:
Heater burnout detection current =
To enable detection in either case, use 7.5 A as the heater burnout detection
current.
The HS Alarm detection function measures the heater current when the con-
trol output (heating) is OFF. For details, refer to the following table.
(HS Alarm detection cannot be used with the control output for cooling.)
Control output (heating)
OFF
Load: Heater (example)
10 A
200 V
To CT input
Load: Heater
10 A
(example)
200 V
To CT input
Current when there is a burnout = 0 A
10
--------------- -
10
--------------- -
Power to heater
Yes (HS alarm occurred)
No (Normal) (See note 1.)
Section 4-5
CT
CT
Burnout
+ 5
≅ 7.5 [A]
2
+ 0
≅ 5 [A]
2
HS Alarm output
ON
OFF
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