Heater Burnout Procedures; Heater Burnout Detection - Omron E5AJ-A2HB Operation Manual

Heater Burnout Procedures

8-1

Heater Burnout Detection

8-2

Heater Burnout Procedures

1, 2, 3...
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To detect heater burnout, wire one of the lead wires for each heater through the
hole of the Current Transformer (CT). The CT generates an AC current accord-
ing to the current flow of the lead wire. The Thermac E5jJ Temperature Control-
ler measures the AC current to check the current flowing to the heater. If any one
of the heaters burns out, the AC current value will decrease so that the E5jJ
turns its heater burnout alarm ON, comparing the AC current value with the heat-
er burnout alarm value.
The E5jJ starts heater burnout detection from the moment the E5jJ is turned
on. If any one of the heaters is turned on after the E5jJ is turned on, the heater
burnout alarm output will be ON because the E5jJ judges that the heater is
burnt out. Therefore, all the heaters must be turned on simultaneously with the
E5jJ or before the E5jJ is turned on. This is essential for smooth temperature
control and fuzzy self-tuning.
The E5jJ will continue temperature control even if the heater burnout alarm is
ON because the E5jJ will continue temperature control using the heaters that
are not burnt out.
Heater burnout detection is possible when the control output is ON. No heater
burnout detection is, however, possible if the control output is ON for less than
190 ms.
The heater burnout alarm output will be held once the heater burnout is de-
tected. To reset the heater burnout alarm output, replace the burnout heater with
a good one and take one of the following steps.
1. Set the heater burnout alarm value to 0.0 A.
2. Turn the E5jJ off and on.
If the difference between the normal heater current value and heater burnout
current value is comparatively small, heater burnout detection will not be stable.
For stable detection, the difference must be 1.0 A minimum if the heater current
consumption is less than 10.0 A and 2.5 A minimum if the heater current con-
sumption is 10.0 A or more.
Heater burnout detection is not possible if the E5jJ has current output, the
heater current is DC, or three-phase heaters are used.
Use the K2CU-FjjA-jGS (with gate input terminals) for three-phase heater
burnout. Refer to the K2CU-FjjA-jGS data sheet specifications for details.
If no heater burnout detection is executed or if no CT is used, set the heater burn-
out alarm value to 0.0 A. The heater burnout alarm value is factory-set to 0.0 A.
Section 8-2