E5CNH E5AN-H E5EN-H Digital Controllers User's Manual - OMRON

Using Heater Burnout, Heater Short, and Heater Overcurrent Alarms Section 3-10
3-10-4 Application Examples
74
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) ≥
1A
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.
The setting range is 0.1 to 49.9 A. Heater burnout, HS, and heater overcurrent
are not detected when the set value is 0.0 or 50.0. When the set
value is 0.0, the heater burnout alarm is always OFF, the HS alarm is
always ON, and the heater overcurrent alarm is always ON. When the set
value is 50.0, the heater burnout alarm is always ON, the HS alarm is
always OFF, and the heater overcurrent alarm is always OFF.
Set the total current value for normal heater operation to 50 A or less.
When a current value of 55.0 A is exceeded, ffff is displayed in the
Heater Current 1 (or 2) Value Monitor and Leakage Current 1 (or 2) Monitor
parameters.
Single-phase Heaters Example: Using a 200-VAC, 1-kW Heater
Normal
200 V
5 A→
←5 A
Product
To CT input
Normal
200 V
15 A→
←15 A
Product
To CT input
AC line
CT
Burnout
Product
To CT input
AC line
Load 200 V
0 A
Burnout
Load Load (such as a heater)
The heater power supply provides 5 A when the current is normal, and 0 A
when there is a burnout, so the heater burnout detection current is calculated
as follows:
(Normal current) + (Heater burnout current)
Heater burnout detection current =
2
= 5 + 0
= 2.5 [A]
2
Example: Using Three 200-VAC, 1-kW Heaters
CT
Load Load Load
Burnout
10 A
200 V
10 A
Product
To CT input
The heater power supply provides 15 A when the current is normal, and 10 A
when there is a burnout, so the heater burnout detection current is calculated
as follows:
CT
CT
Load Load Load
Burnout