Omron EJ1 User Manual

95
Detecting Current Errors Section 4-5
■ HS Alarm Latch and Latch Cancel
The HS alarm latch can be used to keep an HS alarm ON once it goes ON.
The latch can be released by executing an operation command (Reset Error
or Software Reset), cycling the power, or setting the HS Alarm parameter to
100.0 A. Refer to 6-4-11 Operation Commands for details on the operation
commands.
Note This parameter can be set only when operation is stopped.
Installing Current
Transformers (CT)
(HS Alarm)
For details, refer to Installing Current Transformers (CT) (HB Alarm) on
page 88.
Calculating the Heater
Short Detection
Current Value
For details, refer to Calculating the Heater Burnout Detection Current Value
on page 89.
4-5-4 Heater Overcurrent Alarm (OC Alarm)
A heater overcurrent is detected by measuring the heater current while the
control output (heating) is ON. For details, refer to the following table.
(Heater overcurrent detection cannot be used with the control output for cool-
ing.)
Note (1) In the above diagram, it is considered normal if the heater current is less
than the heater overcurrent detection current. When an excessive current
flows in the heater, the current will exceed the heater overcurrent detec-
tion value and a heater OC Alarm will be output.
(2) Heater overcurrents are not detected if the control output (heating) ON
time is 100 ms or less. Detection is also sometimes not possible if a con-
tactor is used for the control output.
Variable type Parameter name Setting range Default
E4/A4 HS Alarm 1 or 2 Latch (I/O) 0: Disabled
1: Enabled
0
Control output (heating) Power to heater
OC alarm output
ON Normal (See note 1.) OFF
Heater overcurrent occurred
ON
Control output (heating)
ON
OFF
ON time
(See note 2.)
OFF time
Variable type Parameter name Setting/monitoring range Default
D6/96
(See note 3.)
Heater Overcurrent 1 or
2 Detection (I/O)
0.0: OC Alarm ON
0.1 to 99.9 A
100.0: OC Alarm OFF
100.0
E4/A4
(See note 4.)
Heater Overcurrent 1 or
2 Hysteresis (I/O)
0.1 to 100.0 A 0.1
C5/85 Heater Current Value 1 or
2 Monitor (I/O)
0.0 to 110.0 A ---
Conditions for use There must be a CT input.

Omron EJ1 Specifications

General

Brand	Omron
Model	EJ1
Category	Temperature Controller
Language	English