88
Detecting Current Errors
Section 5-5
5-5
Detecting Current Errors
5-5-1
Heater Burnout Alarm (HB Alarm)
A heater burnout is detected by measuring the heater current while the control
output (heating) is ON. For details, refer to the following table. (Heater burnout
detection cannot be used with the control output for cooling.)
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 ON
time. If the heater is burned out, the current measured at the current
transformer decreases. When the current falls below the channel's Heat-
er Burnout Detection Value, a heater burnout alarm (HB Alarm) will be
output.
(2) Heater burnouts are not detected if the control output (heating) ON time
is 100 ms or less. Detection is also sometimes not possible if a contactor
is used for the control output.
(3) The HB Alarm can be forced OFF or ON, regardless of the actual heater
current value, by setting the Heater Burnout Detection parameter to 0.0
or 100.0. Use the 0.0 and 100.0 settings to check operation.
(4) The hysteresis setting prevents chattering at the detection point.
Set this parameter in the TC2/4 Unit.
• Turn the heater ON before the EJ1G, or turn both ON simultaneously. If
the heater power is turned ON after turning ON the EJ1G, the HB Alarm
will be output.
• Control will be continued even when there is an HB Alarm.
• The rated current value may sometimes differ slightly from the actual cur-
rent flowing to the heater. Check the current value in an actual operating
state in the Heater Current Monitor Value 1 or 2 parameter.
Control output (heating)
Power to heater
HB Alarm output
ON
Yes (Normal) (See note 1.)
OFF
No (Heater burnout)
ON
Control output (heating)
ON
OFF
ON time
(See note 2.)
OFF time
Variable type
Parameter name
Setting range
Default
D6/96 (See note 3.)
Heater Burnout 1 or 2
Detection
(Channel)
0.0: HB Alarm OFF
0.1 to 99.9 A
100.0: HB Alarm ON
0.0
E4/A4 (See note 4.)
Heater Burnout 1 or 2 Hys-
teresis
(I/O)
0.1 to 100.0 A
0.1
C5/85
Heater Current Value 1 or 2
Monitor
(Channel)
0.0 to 110.0 A
---
Conditions for use
There must be a CT input.
Summary of Contents for EJ1G
Page 3: ...iv ...
Page 17: ...xviii ...
Page 21: ...xxii ...
Page 53: ...32 Unit Configuration Examples Section 2 4 ...
Page 69: ...48 Changing SPs During Operation Section 3 3 ...
Page 81: ...60 Other Functions Section 4 5 ...
Page 145: ...124 Other HFU Functions Section 5 7 ...
Page 167: ...146 Detailed Description of Services Section 6 4 ...
Page 229: ...208 Parameters That Can Be Allocated for Programless Communications Appendix ...
Page 237: ......