Using Heater Burnout, Heater Short, And Heater Overcurrent Alarms - Omron E5 Getting Started Manual

Using Heater Burnout, Heater Short, and Heater Overcurrent Alarms

3-10 Using Heater Burnout, Heater Short, and Heater
Overcurrent Alarms
3-10-1 Heater Burnout, Heater Short, and Heater Overcurrent Alarm
Operations
Control output (heating) status
Control output Operation
(heating) indicator
ON Lit
OFF Not lit
ON Lit
• Heater burnout detection and heater overcurrent detection are executed
by measuring heater current while the control output (heating) is ON, and
heater short detection is executed by measuring heater current while it is
OFF. For details, refer to the following table. (Heater burnout detection,
heater short detection, and heater overcurrent detection cannot be used
with the control output for cooling.)
Power to heater
Yes (Normal) (See note 1.) OFF
No (Heater burnout)
Yes (HS alarm)
No (Normal) (See note 2.)
Normal
Heater overcurrent status
(See note 3.)
ON
Control output (heating)
OFF
Note (1) In the above diagram, power is considered to be ON (normal) if the heater
current is greater than the heater burnout detection current during the Ton
interval. If the heater is burned out, the measured current decreases and
falls below the heater burnout detection value. The output is then activat-
ed as the heater burnout alarm.
(2) In the above diagram, power is considered to be OFF (normal) if the leak-
age current is less than the HS alarm current during the Toff interval. If
the SSR output is short-circuited, the measured current increases be-
yond the HS alarm value. The output is then activated as the HS alarm.
(3) In the above diagram, it is regarded as normal when the heater current is
less than the heater overcurrent detection current during the Ton period.
Current is increased when excessive current flows to the heater, causing
the heater overcurrent detection value to be exceeded and an OC (heater
overcurrent) alarm to be output.
(4) Heater burnout and heater overcurrent are not detected if the control out-
put (heating) ON time (Ton) is 100 ms or less.
(5) HS alarms are not detected if the control output (heating) OFF time (Toff)
is 100 ms or less.
HB alarm HS alarm
output output
---
ON ---
--- ON
--- OFF
--- ---
--- ---
Ton Toff
(See note 4.) (See note 5.)
Section 3-10
Heater overcurrent
alarm output
---
---
---
---
OFF
ON
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