nVent RAYCHEM Elexant 4010i/4020i User Manual
RAYCHEM-AR-H60624-40X0iOpsManual-EN-1905
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Purpose:
This field displays the status of the Limiter temperature sensor. The status can be one of the
following:
OK
– The limiter temperature sensor is reporting a valid temperature reading.
Failed Open
– One or more leg of the RTD is not connected.
Failed Closed
– The common leg of the RTD is shorted to either source or sense leg.
N/A
- The Limiter RTD failed for a reason that cannot be determined (open/short cannot be differentiated
when an IS barrier is installed)
5.13.2.3 Switch Status
Figure 150 - RTD Status
Purpose:
This field displays the status of the Limiter Switch. The status can be one of the following:
Latched Open
– Latching is enabled and an alarm condition has occurred for the limiter. The user needs
to manually reset the alarm.
Open
– An alarm condition has detected by the Limiter and the switch is open. User intervention is not
need to return the unit to normal operation once the condition has cleared.
OK
– The output is closed.
5.13.2.4 Intelligent Limiting
Figure 151 - Intelligent Limiting Setting
Purpose:
This field enables or disables the Intelligent Limiting feature.
When Intelligent Limiting is disabled, the Safety Limiter will trip if the measured temperature rises above
the Safety Limiter’s setpoint, or in the event of a fault. Once the measured temperature returns below the
permissible limit and there are no faults present, power can be restored to the heat trace circuit by
resetting the trip condition using the TRIP RESET button on the front of the unit.
When Intelligent Limiting is enabled, it allows the Safety Limiter to automatically reset itself once the
temperature returns below the permissible limit if there is no current flowing through the heat trace
during the over-temperature event. A few of the scenarios are listed below:
1.
When Intelligent Limiting is enabled, and the Heat Trace is energized when the trip temperature
setpoint is exceeded, the limiter trips and needs to be manually reset once the temperature is below
the setpoint.
2.
When Intelligent Limiting is enabled, and the Heat Trace is de-energized when the trip temperature
setpoint is exceeded, the limiter trips and will reset automatically once the temperature is below the
setpoint.
