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If the control temperature crosses an alarm threshold, the Temperature Alarm Time Delay begins counting down. If the timer expires and the temperature
has not returned past the alarm differential, the red alarm LED on the controller (and optional display) illuminates. If the control temperature returns past the
threshold by the amount of the differential before the alarm delay expires, the pending alarm is cancelled, and the timer is reset. When the temperature
returns past the threshold by the amount of the differential the alarm is cancelled and the Temperature Alarm Time Delay is reset. The Temperature Alarm
Time Delay reduces the possibility of temperature fluctuations causing false alarms.
A Temperature Alarm Disable Time after Start up timer prevents alarms while the appliance decreases the temperature after being powered on. A
Temperature Alarm Delay After Defrost prevents false alarms while the appliance decreases the temperature after defrost. This allows for a shorter
Temperature Alarm Time Delay and a longer delay time after defrost only.
5.1.5.2 Faults
If a sensor circuit is shorted or open, the Sensor Fault Monitoring Time timer starts counting down. If the timer expires before the fault is corrected the red
alarm LED flashes. Refer to 5.1.7 Sensor failure mode. When the fault is fixed, the timer resets and the red alarm LED is extinguished (if a temperature alarm
is in effect the LED is illuminated). If a sensor failure alarm and a temperature alarm occur at the same time, the red alarm LED flashes to indicate the
sensor failure.
During a control sensor failure, the optional display shows E1.
During an evaporator sensor failure, the optional display shows E2 for one second, the temperature of the control sensor for three seconds, and repeats.
If both sensors fail, the display shows E1.
NOTE: When the controller is powered on, an LED flashing sequence indicates that the controller firmware is operating properly. Each LED flashes for
one second in sequence and then all three illuminate for two seconds. If the red alarm LED remains illuminated after the controller is powered
on, a check sum error has occurred and the controller’s firmware must be updated using a computer and the interface box or a copy card (refer
to 6.2.8) No additional external alarm indication is available.
Type E7 EcoCool™ Electronic Temperature and Defrost Controllers
©2008 Invensys Controls All rights reserved.
DRAFT VERSION
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