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the cable, it will eventually trip its output switch off and will not retry or pulse its output switch
again. At this point the OVERCURRENT TRIP ALARM is latched on.
IMPORTANT:
• The controller is NOT a safety cutout or an overcurrent protective device as defined by the
National and Canadian Electrical Codes (NEC and CEC). A protective device such as a circuit
breaker or fuse must be included as part of a proper design and be selected in accordance
with the requirements defined in the National Electrical Code (NEC) and/or the Canadian
Electrical Code (CEC).
• The controller cannot protect the SSR from short circuits or excessive overcurrent
conditions. Always ensure that the power is off prior to performing any maintenance or
troubleshooting of the heating circuit. Verify that no damage has occurred to the cable or the
controller prior to re-energizing the circuit.
Alarm Mask: ENABLE or DISABLE
Procedure: Adjust the SWITCH CURRENT RATING setting to the actual current rating of the
SSR. Enable or disable the alarm as required. Note that the OVERCURRENT TRIP ALARM does
not have to be enabled in order to adjust the SWITCH CURRENT RATING setting.
IMPORTANT: It is highly recommended that this alarm be left enabled since an overcurrent
trip con- dition would normally represent a serious problem. Note that this is a factory set
alarm value and disabling the alarm does not disable the overcurrent trip function. In some
applications the use of self-regulating cable will produce very high in-rush currents during cold
startup. These currents may exceed the overcurrent trip limit and the controller will not be able
to soft start the trace circuit. If this condition persists please contact your nearest sales office
for recommendations and solutions to this problem.
5.5.18 SWITCH FAILURE ALARM
Purpose: The purpose of the SWITCH FAILURE ALARM is to indicate that an output switch
failure has occurred. The controller determines that if the output switch is turned off and there
is load current present, then the output switch has failed closed and the alarm is latched on.
Alarm Mask: ENABLE or DISABLE
Procedure: Enable or disable the alarming of an output switch that has failed in the closed
position.
IMPORTANT: The SWITCH FAILURE ALARM SHOULD ALWAYS BE ENABLED. A high temperature
condition as a result of a failed circuit can only be caused if the output switch fails closed. When
an output switch fails closed, the controller cannot turn the tracer off; therefore, no protection
features are available (ground fault trip, power limiting, etc.). If a SWITCH FAILURE ALARM is
detected, the unit should be serviced immediately.
5.5.19 HTC RESET ALARM
Purpose: The HTC RESET ALARM is used to indicate:
1. Power to the HTC has been interrupted and subsequently restored.
2. A transient has caused the HTC’s microprocessor to restart.
3. An internal condition has caused the HTC’s microprocessor to restart its program.
Alarm Mask: ENABLE or DISABLE
Procedure: Enable or disable alarming on reset as desired.
IMPORTANT: Normally the HTC RESET ALARM is left disabled since powering the controller
off and on for maintenance or trouble-shooting would require the user to reset this alarm every
time. If the particular installation includes a Model 780/GCC-9000, this alarm may be left enabled
since resets are not considered normal occurrences and the Model 780/GCC-9000 provides the
capability to easily log and reset alarms such as these. The difference in time between when a
COMMUNICATIONS FAIL ALARM and an HTC RESET ALARM are logged provide an indication of
how long the circuit has been “OFF.”
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